VeloNews.com » Lennard Zinn http://velonews.competitor.com Competitive Cycling News, Race Results and Bike Reviews Thu, 03 Sep 2015 03:20:33 +0000 en-US hourly 1 http://wordpress.org/?v=4.0.1 Technical FAQ: Road disc vibrations, SRAM eTap, and more http://velonews.competitor.com/2015/09/bikes-and-tech/technical-faq/technical-faq-road-disc-vibrations-sram-etap-and-more_383399 http://velonews.competitor.com/2015/09/bikes-and-tech/technical-faq/technical-faq-road-disc-vibrations-sram-etap-and-more_383399#comments Tue, 01 Sep 2015 16:32:16 +0000 http://velonews.competitor.com/?p=383399

Are disc brakes like this one the cause for reader Nick's problems? Photo: Logan VonBokel | VeloNews.com

Lennard Zinn tackles questions about a perplexing problem involving road disc brakes and a titanium frame, SRAM eTap, and other topics.

The post Technical FAQ: Road disc vibrations, SRAM eTap, and more appeared first on VeloNews.com.

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Are disc brakes like this one the cause for reader Nick's problems? Photo: Logan VonBokel | VeloNews.com

Vibrations using road discs

Dear Lennard,
I have a 2009 Motobecane Cross Ti bike that my local bike shop converted from cantilevers to TRP Hy/RD brakes a few months ago. We also installed Stan’s NoTubes Grail wheels with a Spot Brand fork up front; the rear stays already had disc tabs. I ran through the recommended brake wear-in procedure, but after 5-10 miles I started feeling vibrations, most noticeably in the front, but also in the rear. Light braking doesn’t produce any vibes, but with medium or hard pressure I start feeling vibes front and rear at about 12 mph (high frequency, like the rotor cutouts hitting the pads) and getting progressively stronger and lower frequency until I can see the fork vibrating front-to-rear (~approximately 3mm) when the speed is down to 3-5 mph. At low speed it also produces a solid thunk-thunk sound that riders next to me have noticed.

We’ve checked the headset and it’s not loose. Same for the calipers on the fork and rear stay. The rotor bolts are tight and the rotors are true, and not touching the pads. I’m using 160mm rotors front and rear.

I’ve cleaned the rotors and pads several times with alcohol and degreaser. It seems to stop the vibes for the first five miles of the next ride, but then the vibes return.

Last month, the shop tried replacing the OEM rotors with Tektro HZs, and the original metallic pads with organic pads, but it didn’t help. I’ve tried three different QR skewers, and tried reversing the lever from left to right, with no effect. I also tried running a friend’s front wheel with an Avid HS1 rotor. The vibes seemed to disappear for the first 10 miles, but then returned.

I would certainly appreciate any further diagnosis that you can think of, or recommended fixes.

Are TRP Hy/RDs noted for this problem? How about the Spot fork? Should I try some more pad-rotor combos?
— Nick

Dear Nick,
Here is a response from TRP’s technical service manager:

This one is a bit of a head-scratcher. He’s already tried just about everything I can think of that typically fixes any issues. There are two things that come to mind right away, but they’re both pretty extreme.

The first would be that the calipers are aligned slightly askew. Not enough for the rotor to rub on the pads, but enough that they still contact on an angle. We generally only see this with the Spyre brake, because the pad to rotor gap can be adjusted and if left far apart can allow for a greater range of mounting angles. I don’t recall this ever being an issue with the HY/RD. A more thorough explanation can be found in this video.

The second would be both the frame and fork are flexing under the braking load. This is more common with forks than with frames, but both cases are very rare. Although with it being an older Motobecane frame, I wouldn’t completely rule it out. It is strange that the vibrations disappear with a new rotor, pads or after cleaning, but come back after some time.
— Bryce Olsen
TRP

I would add that when we’ve seen issues like this, it is due to the brake vibrations being carried up into the frame or fork due to something flexing to the point that it can set up the vibration in frame or fork tube. On the rear, we have fixed this on metal frames by reinforcing the seatstay to deaden the vibration. I believe that yours already has a strut between the seatstay and the chainstay to do that, but it is still a thin seatstay, and it’s titanium, which really likes to vibrate (a titanium tuning fork rings so brightly and loudly it is almost deafening; same thing if we drop some titanium tubes on the concrete floor; everybody covers their ears!).

You can do an experiment to try to deaden the frame vibration. Cut and miter a ¾-inch or so wooden dowel rod to form the third leg of an isosceles triangle near the dropout; have it intersect the left seatstay and chainstay about four inches from the dropout on each of them. Wrap tape around the seatstay and chainstay first where it meets them, and then tape it in really well with duct tape. If that eliminates the vibration from the rear brake, you’ll know the source. On the front, my guess is that a different fork would do the trick. I have seen brake chatter on disc cyclocross bikes go away with a fork change, and yours moving back and forth 3mm sound a lot like that.
― Lennard

SRAM eTap compatibility

Dear Lennard,
With the advent of SRAM’s eTap, I bet a lot of people are thinking like I’m thinking … can I put eTap on my bike with Ultegra cranks and Ultegra cassette and roll? Or do I have to match with a SRAM crankset/cassette?
— Jonathan

Dear Jonathan,
We won’t know for sure until it comes out, but given that you can currently run Ultegra cranks and an Ultegra cassette with a SRAM road drivetrain of the same number of speeds, I’m willing to bet that you’ll also be able to with eTap.
― Lennard

More on shortening cranks so kids can ride a tandem

Dear Lennard,
Sinz cranks go down to 115 mm in square taper. How short does this guy need for his kids? Other BMX brands go down as low as 130 mm.
— Larry

Dear Lennard,
SJScycles in the UK have a range of crank sets that might be useful for accommodating small children. One has dual drillings at 115mm and 140mm, others are at 125mm, 140mm, and 145mm.

Look for the Thorn brand cranksets on sjscycles.co.uk or try this link.
— Blair

Dear Lennard,
FYI, there is a company making kid-sized bikes with various age appropriate length cranks. Not sure if they sell just parts. Starter kids Bikes weigh 15 pounds! Islabikes. It’s a company founded by Isla Rowentree, a master’s woman cyclocrosser with many victories from England. In the USA you have to buy them through one shop. Big market though in Britain. We love ours.
— Brian

Dear Lennard,
Based on experience with my own kids and a tandem, I recommend (loose) toe clips for the kids. My daughters preferred clips as they would mitigate their feet sliding off the pedals and getting hit by the pedal. With clips the kids routinely did a cadence of around 90!

Also, for their comfort and safety, the kids should be wearing more substantial shoes than the ones shown in the picture.
— Raymond

Dear Lennard,
Just saw your recommendations on shortening crank arms. When I built up a tandem to take my eight-year-old daughter to school and for weekend breakfast trips, I investigated a number of options. Ultimately I didn’t want to spend a lot on something she would outgrow in a couple of years. I’m a cheapskate, and she’s growing like a weed. So I cut some 2x4s about four inches long, sandwiched the pedal between them, and then attached the 2x4s with 3” screws. It’s not an elegant or lightweight solution, but it’s worked for the past six months. I might eventually add some sandpaper tape for grip, but right now she doesn’t really “pedal” that much anyway.
— Brian

More on wheels for big guys

Dear Lennard,
Just a note to your clydesdales. We’ve found the Campagnolo Khamsin (or Fulcrum Racing 7) to be pretty much bulletproof. Had a guy this year with us blow up his Mavic rear wheel and the shop guy reminded me of the reputation for strength and reliability of these wheels when he suggested them as replacement … and that was far from the first time I’ve heard this. The latest ones are wider as well.

Not expensive, fancy or light, but big guys shouldn’t be too concerned about that anyway.
— Larry

The post Technical FAQ: Road disc vibrations, SRAM eTap, and more appeared first on VeloNews.com.

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Technical FAQ: Clydesdale road wheels http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-clydesdale-road-wheels_382653 http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-clydesdale-road-wheels_382653#comments Tue, 25 Aug 2015 15:11:02 +0000 http://velonews.competitor.com/?p=382653

Photo: Caley Fretz | VeloNews.com

Lennard Zinn explains the fundamentals of why wheels fail when ridden hard by heavier riders and how to build a stronger wheel.

The post Technical FAQ: Clydesdale road wheels appeared first on VeloNews.com.

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Photo: Caley Fretz | VeloNews.com

Dear Lennard,
I took my bike in for its break-in tune-up and was told that the back wheel already needed some re-truing. I did some homework and found a few articles saying that riders over certain weights should seek out certain wheels. I wanted to know if you give any “weight” to this argument. I emailed Rol wheels, since they advertised wheels for Clydesdale riders and found that their upper limit was 240 pounds. While I am on my way there, and should be around that weight by the start of next season, the guys at Rol recommended I look at Wheelbuilder.com and get a 32-spoke rear wheel. Is this, in your opinion, something I should look into? Just looking for a set of alloy wheels that are built for a larger individual that will still be fun to ride.

That being said, would you have a recommended starting point on the site? When looking through Wheelbuilder.com I had been looking at the Pacenti SL23 Rim since it was a wider rim that created a bit wider tire profile.
— Mat

Dear Mat,
Yes, I’d give some “weight” to this argument! It’s not just weight but also riding style that’s important.

An obvious wear factor on a wheel is impact — a guy who unweights the bike for train tracks or potholes will have less impact damage than the guy who bangs into everything fully weighted on the saddle. And, of course, the greater the weight (force) on the wheel on impact, the greater the damage it will sustain.

But often, more important than impacts for wheel durability, is fatigue, and that is dependent on weight and also on smoothness of the pedal stroke. At least half of the customers buying bikes or cranks from my company are over 250 pounds, and the ones with a hitch in their pedal stroke crack rear rims on factory-built wheels at every drive-side spoke nipple in short order. We have some 300-pound customers who get quite decent wheel wear, and some who break everything in no time — they break the hub flanges, as well as the spokes, and crack their rims.

The spokes loosen up because, as the wheel rolls, the section at the bottom becomes flattened (D-shaped). If you’re heavy enough, that flat spot is deep enough that it totally de-tensions the spoke that is at the bottom, since the nipple has lost contact with the rim. This allows each spoke to jiggle during that moment it’s at the bottom without tension and, over time, consequently unscrew.

Furthermore, as the wheel continues rolling, the flattened section of rim snaps back to its original shape, abruptly bringing that spoke that had been at the bottom back to full tension. If the spoke had been completely de-tensioned, the bang-bang-bang of the impact of the rim snapping back against the nipple with every single wheel rotation will fatigue not only the spoke, but also the rim at that spoke nipple. This will cause the rim to crack over time at each spoke nipple.

Rim cracking at each nipple is a bigger issue with aluminum spokes, because aluminum has less elasticity; an aluminum spoke is not stretched as much as a thin, steel spoke would be, so its nipple loses contact with the rim with less deformation of the rim when it is at the bottom. Thus, it requires less load on the wheel for that bang-bang-bang fatigue process to crack the rim if it’s built with aluminum spokes than if it’s built with steel spokes.

This is also why a double-butted steel spoke will result in longer life of both the rim and the spoke than will a straight-gauge steel spoke — because its thinner center section will stretch more at the same overall spoke tension. This keeps the nipple in contact with the rim better as it rolls, and its thicker ends will still protect it where the stress is most concentrated.

In general, higher spoke counts and stiffer rims are friends of a heavy rider.

Rich Sawiris at Wheelbuilder.com is indeed fantastic at making wheels for big guys, and he wrote this in response to your question.

“The Velocity Dyad is a better option than the SL23 from Pacenti. The Pacenti has a relatively thin cross section across the nipple bed and we have started using load-distribution washers to prevent cracking. Another rim that would do a good job for a heavier rider is the Hed Belgium Plus in a 32H drilling. If weight is not a factor, the strongest rim I can think of would be a Velocity Chukker. The Chukker will do the trick for sure, but many people are turned off by its 640g rim weight.

For hubs, I recommend using something with the largest-possible axle diameter. Some popular options would include Chris King R45, Industry Nine Road Torch, White Industries MI5, and the DT 350 hubs. The 350 hub uses larger bearings than the 240S, which makes it a better candidate for heavier loads.
— Richard Sawiris, P.E.
Wheelbuilder.com”

I agree wholeheartedly with Rich. We build lots of wheels with Velocity Dyad rims; it has been our go-to wheel for big guys for a couple of years, and we have yet to hear a single complaint from any of the 250-pound-plus riders we’ve sold them to.
― Lennard

Dear Lennard,
When I read this article, I remember you discussing a cleat position moved farther back toward the middle of the sole.

According to me, this would help keep the Q-factor in check, as despite still having the need to increase the Q-factor, it could be considerable less.
It also might mitigate some of the physical distress to the body as described.
— Reginald

Dear Reginald,
Wow, you have a good memory. That goes way back. I imagine you mean articles I’ve written regarding the center-cleat theory of Götz Heine. They were so long ago, I can’t even find them in my hard drive.

Yes, I imagine you are right; Colin could get his foot angled farther outward with fewer issues of heel clearance and further forward stagger of his right leg relative to his left if his cleat were centered on the shoe sole.
― Lennard

The post Technical FAQ: Clydesdale road wheels appeared first on VeloNews.com.

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Technical FAQ: Shortening cranks for kids, saddles, and compatibility http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-shortening-cranks-for-kids-saddles-and-compatibility_381702 http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-shortening-cranks-for-kids-saddles-and-compatibility_381702#comments Tue, 18 Aug 2015 14:29:41 +0000 http://velonews.competitor.com/?p=381702

Reader Al's full setup while riding with his kids.

Lennard Zinn tackles reader questions about, among other topics, adjusting cranks for children to use safely.

The post Technical FAQ: Shortening cranks for kids, saddles, and compatibility appeared first on VeloNews.com.

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Reader Al's full setup while riding with his kids.

Adjusting cranks for kids

Dear Lennard,
My wife and I plan to do some touring with our kids over the next few years, so I picked up a triplet and have set it up with a “kid-back” drop crank for our smallest (almost 4 years old) stoker and bolt-on crank shorteners for our biggest (almost 6 years old).

Recently, after about a 12-mile ride, my oldest daughter complained about the cranks hitting her ankle. The crank shorteners move the pedals outward a good half inch on each side, not only causing interference but also significantly increasing the Q-factor.

So, my first question is: Do you know if such a high Q-factor is a concern for a growing body? Especially if we build our way up to significant miles (our goal is to do 40-50 miles a day for several days at a time)?

One option I have read about and would be comfortable doing that would solve both the Q-factor and the interference problem is just drilling and tapping the crank arms and shortening them permanently. My daughter weighs less than 50 pounds so I’m not very concerned about her generating enough torque to break a crank modified in such a way (please let me know if that is foolish thinking). However, this would mean making a new set of cranks every time she has a significant growth spurt. (They are good old-fashioned square drive so this would not be exorbitantly expensive but still seems sub-optimal).

I know you make custom cranks so I thought you would be the best person to ask. Is there another option for shortened, adjustable cranks that don’t increase the Q-factor so much? Or that don’t leave so much crank extending above the pedal at the top of the stroke where it hits the rider?
— Al

Dear Al,
I think it is a poor idea to subject small, growing kids to extended periods of ultra-wide Q-factor. Because of their short legs, the same Q increase that might angle our legs out slightly will splay their legs out at an extreme angle. And then, with the mileage you’re planning on, repeatedly turning their hips and knees through the pedal stroke for hours on end when the articular surfaces in their hips are bearing on areas they are not meant to because of the leg angles could do some damage. Of course, at that age, all of their synovial fluid is flowing nicely, and all of their articular surfaces are super smooth and nearly friction-free, but to subject them to such sub-optimal ergonomics seems like a gamble you don’t want to take. As in the photo you sent, her feet automatically come way in, since that is what her body naturally prefers, but constantly banging her ankles on the cranks is not nice, either.

There is nothing wrong with drilling and tapping the cranks shorter for small kids, as long as you drill the pedal holes parallel to the bottom bracket spindle. I used to do this on numerous cranks when my kids were small, and those bikes continue to get handed down to family and friends, never with any problems.

You need to use cranks that are not hollow and are wide enough to provide enough material around a hole drilled along its length. Since cranks are generally splayed-out for chainstay clearance, the pedal threads are not perpendicular to the crankarm. Thus, you can’t simply clamp the arm and drill it or you will end up with a pedal that precesses wildly around a changing axis, rather than around the bottom bracket, as the crank goes around.

Clamp the spider arms of the drive crank flat on the drill press platform (or, better, milling-machine table), and drill the new pedal hole straight. Then put the tap for the pedal threads in the drill press chuck to hold it straight, and turn it by hand (with plenty of cutting fluid). Similarly, with the non-drive crank, use the small flat on the back of the crank head where it meets the spindle as an index for holding that one perpendicular while you drill and tap it.

Another option is an adjustable crank with normal Q-factor. This one is great.
― Lennard

Matching proper saddle setback

Dear Lennard,
Your garage door method to match proper saddle setback is brilliant! To match proper setback on bikes with different saddles, do you recommend measuring from the wide point of the saddle, which differs from saddle to saddle, instead of the nose of tail? I have a Specialized Toupe, Specialized Romin, and Selle Italia saddle on different bikes, and each one has a different wide point, although they are all about 27cm long.
— Chris

Dear Chris,
Actually, I measure all of the saddles to the sit-bone contact of the rider. If they are not identical saddles, I definitely measure neither to the nose nor to the tail.

I feel for where my sit bones are contacting the saddle as I pedal. I mark these points and draw a line between them across the saddle with a paint pen; I measure out from the garage-door channel to that line. I do that on all of the saddles of all of the bikes I’m matching. And, if the readjustment of the saddle and handlebar position is significant, as I get closer to dialing in the position, I re-check (and re-mark if need be) the positions of the sitbones on the saddle, since that may change as the relative positions of the saddle, pedals and handlebars change.
― Lennard

Mixing drivetrain parts

Dear Lennard,
I have M980 shifters (XTR 10-speed), and I want to use a road crank, say an Ultegra FC6800 52-36 combination, so I’ll need a front derailleur flat bar style FD-R770?

My rear derailleur is XTR 10-speed (M986) with a 10-speed cassette of 11-34.

My question is, because Shimano specified it as an “11-speed crank,” would it be compatible to my setup?
— Paramount X

Dear Paramount X,
Yes, that crank will work fine with your chain and rear derailleur.

I’m not sure if that front derailleur will work with your left shifter. The SL-R780 would be the standard shifter for that front derailleur. Since you’re committed to it, you might as well give it a try and let us know how it works. If you have to get a left road flat-bar shifter, the additional expense relative to that crank you’re buying is minimal. As you probably know, Shimano does not use the same cable pull on road and mountain 10-speed rear derailleurs (so right hand SL-R780 and SL-M980 levers are not interchangeable), so it may not use the same cable pull on road and mountain front levers for 10-speed systems.
― Lennard

Dear Lennard,
Will an XTR 11-speed 11-40t cassette work with SRAM Force 1 long-cage rear derailleur and shifters? This would get me nearly the range of a SRAM 10-42 without upgrading my rear wheel to an XD freehub. Would I have to use the XTR asymmetric chain, or will any 11-speed chain work?
— Todd

Dear Todd,
Yes, that cassette will work with that SRAM Force 1 drivetrain. Any 11-speed chain will work, although I imagine that the XTR asymmetrical one might work slightly better, since it was designed specifically for that cassette.
― Lennard

The post Technical FAQ: Shortening cranks for kids, saddles, and compatibility appeared first on VeloNews.com.

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Technical FAQ: Testing aero helmets http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-testing-aero-helmets_381181 http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-testing-aero-helmets_381181#comments Tue, 11 Aug 2015 13:44:57 +0000 http://velonews.competitor.com/?p=381181

Giro's new Synthe helmet provides many of the aero advantages of other helmets without the unsightly aesthetics. Photo: Caley Fretz | VeloNews.com

Lennard Zinn tackles a question about an aero helmet test one reader says has "fuzzy" parameters.

The post Technical FAQ: Testing aero helmets appeared first on VeloNews.com.

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Giro's new Synthe helmet provides many of the aero advantages of other helmets without the unsightly aesthetics. Photo: Caley Fretz | VeloNews.com

Dear Lennard,
I’ve bought into Giro’s helmet technology in a big way. I own an Air Attack Shield and Synthe, so imagine my disappointment having read this “independent” test.

Have I been taken for a “marketing mug,” or are the test parameters so fuzzy that no one can lay claim to the definitive best/fastest helmet?
— Mick

Dear Mick,
I would pay attention to the comments at the bottom by Giro’s Rob Wesson. From having doing lots of wind tunnel tests myself, I know that “garbage in, garbage out” applies as much to aerodynamic testing as it does to computers. I’m by no means saying the test was garbage, but the fact is that:

— There are many different ways that riders hold their heads on the bike.
— People have different shapes of heads and ears and necks, with different sizes of helmets that may test differently relative to each other.
— There are many different wind angles, as well as speeds, that riders encounter.

This test seems to have only tested one head shape, one head position, and one wind angle (straight on). And the point Wesson makes about inconsistency of strap taping seems valid; when you’re talking about the small amount of total drag involved here, the presence or absence of a single flapping strap can be significant.

Still, CyclingNews should be commended for going beyond marketing hype and taking these helmets into the wind tunnel. I’m not sure a perfect test for aero helmets exists, but I’m certain that this is better than no test at all. It’s generally also true that the first stab one makes at testing something is not definitive. I’m sure they learned from this test and have plans for how to improve it.

I remember the first time I went to do some wind tunnel testing at Texas A&M in 1989, a new company named Camelbak was there. I saw them running tests with riders on aero bars in the tunnel with early water-filled Camelbak hydration packs on. It was visually obvious that the backpack was providing more drag than no backpack would. However, I later saw claims from Camelbak to the effect that wind tunnel testing at Texas A&M showed that their hydration packs were more aerodynamic than a water bottle! I dug deeper into this with the guys who performed the test, and it turns out, the comparison was made between wind tunnel results of a guy riding while sucking on the hose of his hydration pack and a guy riding while drinking out of a bottle! So you could not say that they were lying, because the results indeed showed that in this one instance, the rider with the pack was faster, but leaving out how it was done was misleading. It leaves out the fact that you always have the drag of the hydration pack when riding with it, but you only occasionally have the drag of holding up a water bottle to your mouth while riding with one of those!

I would not make the assumption that people who work on helmets all the time don’t know what they are talking about when they say their helmet is faster than others. On the other hand, I suspect there are lots of things we don’t know about how helmet brands test their aero lids in wind tunnels and that they may very well be reporting the one set of circumstances that favors their helmet and neglecting to report the results of other tests using different parameters in which their helmets fare poorly. The million-dollar question, and the one you are not likely to get answered by manufacturer claims of performance, is whether the favorable results for the product apply to you when you’re the one riding with it on.
― Lennard

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Technical FAQ: Powertap rim choices and disc-brake cleaning http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-powertap-rim-choices-and-disc-brake-cleaning_380494 http://velonews.competitor.com/2015/08/bikes-and-tech/technical-faq/technical-faq-powertap-rim-choices-and-disc-brake-cleaning_380494#comments Tue, 04 Aug 2015 18:06:21 +0000 http://velonews.competitor.com/?p=380494

Lennard Zinn helps a reader sort out rim options for his Powertap and considers cleaning techniques for disc-brake road bikes.

The post Technical FAQ: Powertap rim choices and disc-brake cleaning appeared first on VeloNews.com.

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Dear Lennard,
I currently have a Cycleops Pro Powertap rear road wheel (rim brake). It is a 32-spoke hub laced to a Cycleops rim, which I think might be a rebranded Velocity aluminum rim. I have the matching front wheel but wanted to re-build them into a nicer carbon-rimmed wheelset, keeping the Powertap hubs. Most of the carbon rims I’ve looked at have fewer drilled holes, like 18, 20, 24 count. Do you know of any 32-hole carbon rims? I don’t really race or TT, so I don’t need anything with a deep profile, and I am less concerned about weight.

Secondly, assuming I find a compatible carbon rim, can I use a bladed spoke like Sapim spokes? I think I’ve heard you can only use regular spokes laced in a certain pattern for the Powertap hubs. I was wondering if you happened to know this as true?
— John

Dear John,
Here is the response from Rich Sawiris, owner and founder of Wheelbuilder.com, expert on wheels and making them with Powertap hubs.
― Lennard

“There are no great options for 32H carbon road rims, however it is possible to swap the hub shell on the Powertap Pro for a different hole-count. We still have a few Pro model shells around the shop that would allow the transfer of an existing torque tube for a lower spoke count. A 24H count would give you the greatest number of carbon rim options from every major manufacturer.

Bladed spokes are fully compatible with a PowerTap hub if the major dimension of the blade does not exceed 2.6mm. The most popular options are the DT Aerolite, Sapim CX-Ray, and DT AeroComp models. The PowerTap hub requires a minimum 2-cross lacing pattern on the non-drive side flange, but we recommend it on both flanges. Typically, we would lace a 24H hub with 2X lacing and a 28H or 32H hub with 3X lacing.”

Dear Lennard,
Can you provide advice on cleaning road bikes with disc brakes — techniques, cleaner, etc.? The way that I clean my bike seems to be associated with having grease or grime on my front pads (and in turn producing loud squealing and reduced braking power) a few rides after my cleaning. My LBS is guessing that my use of dish soap and water to clean the frame may be the source of the problem. More generally, with the growth of disc brakes on road bikes, there might be great interest among VeloNews readers in an article on proper cleaning of road bikes with disc brakes. At least it would be of interest to this reader.
— Todd

Dear Todd,
Here are answers from a number of disc-brake product managers.
― Lennard

From FSA’s Joel Richardson (formerly with Hayes):
“The safest route when cleaning the bike would be to remove the front and rear wheels, remove the brake pads and install the bleed spacers that come with the brakes. This will ensure that the pads and rotors are not contaminated during the cleaning. The bleed spacer will prevent the caliper pistons from getting pumped out if the brake lever is bumped while cleaning.

“Now this is a bit of a process and inconvenient if the user cleans their bike after every ride. Most disc-brake manufacturers recommend isopropyl alcohol to clean the rotors and disc-brake components. However, mild dish soap and warm water is also acceptable. With this in mind, I suspect that the soap and water is not the root cause of the noise for your reader. Instead, the grease and road grim that the soap and water are washing off the bike and drivetrain may be making their way on to the rotors and/or brake pads. If this is the case, then the pads will need to be replaced and the rotor cleaned per above.

“Another possible cause for the noise and loss of power relates to burnish. The brake pad material is transferred to the surface of the rotor and this in turn creates the friction needed to stop the bike. It is possible to remove some of this material when cleaning with soap and a brush. On the next ride the pads will make noise and power would be low until the burnish process has been completed again. If the power has not returned and the noise continues after 15-20 good stops from 10mph then the pads may be contaminated.

“Basically, we’ve been cleaning disc brake-equipped mountain bikes since 1998 with soap and water and have never seen an issue related to the soap.

“One final possibly is related to drivetrain maintenance. Mountain bikers have learned that you must be cautious when cleaning and lubricating your chain and derailleurs. Overspray from cleaners or spray lubes can easily pass through the spokes on to the rear rotor. The next time the brake is applied, these contaminants are transferred to the brake pads, and it’s time for new pads.

“Hope this helps you with your column. As mountain bikers, we are accustomed to the nuances of disc brakes. With the introduction of road disc brakes we have a new group of riders that may not be aware of all the tips we’ve picked up of the last 17 years.”

From Eric Schutt, media manager for Hayes:
“When washing a bicycle with disc brakes, we suggest using isopropyl alcohol to clean the rotors. It’s best to avoid any detergents, chemicals, or lubricants from coming in contact with disc brake rotors and pads. If you wanted to go the extra step, you can use a clean, lint-free towel to clean the pads. You can either run a towel thru the brake slot in the caliper, or remove the pads to clean them.”

From Stefan Pahl, product manager at Magura:
“We haven’t got experience with road disc brakes, but with MTB disc brakes, and they should be identical.

“We recommend cleaning rotors with soapy water and a clean brush. But you can also use disc cleaner sprays or alcohol. Make sure to always use clean rags or towels!

“Be careful when using brushes or sponges when cleaning with soapy water, which are not clean and might have some grease or oil residue from the drivetrain. This can contaminate the rotors/pads.

“Contaminated pads, especially with organic compounds, have to be replaced. The oil or grease is soaked up by the pad material like a sponge, the pad will never perform equal after cleaning.

“Other advice: Be careful when lubing the chain when using sprays. Never let oil mist get onto the rotor.”

“Some bike cleaner sprays contain oil or other lubricants to make the bike shine and repel water. They will also contaminate the rotors and pads.”

From Bryce Olson, customer service representative at TRP:
“Cleaning and washing a road bike with disc brakes definitely presents some issues when it comes to keeping the pads and rotors free of contaminants. Hands down, the best way to avoid squealing pads as much as possible is to remove the pads before washing the bike. Granted, this takes a few extra steps and a little more time, but is the best way to avoid the issue. Any pad that gets wet, whether it’s contaminated or not, is more likely to squeal than a dry pad for a while until they dry out. While we haven’t done any scientific or dedicated testing, in our experience using a bike-specific wash instead of dish soap tends to cause less noise issues. Finally, cleaning the rotors separately, after washing the bike, with isopropyl alcohol to remove any residue or contaminants before using the pads is highly recommended to help keep the pads clean and contaminant-free.”

The post Technical FAQ: Powertap rim choices and disc-brake cleaning appeared first on VeloNews.com.

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Technical FAQ: Drafting an aero bike and derailleur setup http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-drafting-an-aero-bike-and-derailleur-setup_380048 http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-drafting-an-aero-bike-and-derailleur-setup_380048#comments Wed, 29 Jul 2015 22:45:30 +0000 http://velonews.competitor.com/?p=380048

There is plenty of data (and marketing info) out there to paint a clear picture of the benefits of aero-focused frames — but how does an aero frame affect a rider in its slipstream? Photo: Tim De Waele | TDWsport.com

Lennard talks drafting science and derailleur setup in this week's Tech FAQ

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There is plenty of data (and marketing info) out there to paint a clear picture of the benefits of aero-focused frames — but how does an aero frame affect a rider in its slipstream? Photo: Tim De Waele | TDWsport.com

Dear Lennard,
With all the hoopla about aero bikes, do they provide a better draft for the guy riding behind? Perhaps no different when directly behind but maybe at certain angles?
— Freddy

Dear Freddy,
Certainly when riding directly behind an aero bike, there is less draft. In a crosswind, I suppose it’s possible that there might be more draft since it would tend to have a higher side surface area, but if the aero bike is also efficient in a sidewind, then it also should not be providing as much draft as a standard road bike. That’s because draft is a function of turbulence—the more turbulence, the more draft. But aerodynamic efficiency means that turbulence behind the object is reduced—that the wind reattaches better coming off of the object. So, I wouldn’t count on finding more draft behind an aero bike whether straight behind or off to the side in a crosswind.
― Lennard

More on gear range combinations

Dear Lennard,
How thick should the washer be between the mech and hanger to use a 11-32 tooth cassette on a short cage mech?”
— Mike

Dear Mike,
Tim has successfully used a 32T rear cog and a short-cage rear derailleur with his spacer method. He provided this answer to your question and even included a photo of his washer!

I’ve been using a 1mm thick washer to gain an extra few teeth. Specifically, it’s a 1mm x 10mm ID x 20mm OD washer. I filed down one side to clear the b-screw and tab, and it fills out the space behind the knuckle nicely. I’ve fit a 32t 10-speed cassette with an Ultegra 6700 derailleur (I did have to also run a longer b-screw). Of course, each frame’s hanger will vary the effect, but this can always help. I’ve attached a photo [above] for clarity.

I figured this out when I had a thin-hangered frame with a cheap derailleur that wouldn’t shift to the smallest cog (A Yuba Mundo cargo bike, so a long cable run, to boot). At first I thought it would just help get the derailleur back in the spring tension zone, but when I had to let off on the b-tension, I knew I had a really useful trick on my hands.

I wouldn’t recommend more than 2 spacers, although I haven’t really tried a third. I suppose it mostly depends on how solidly you can bolt your derailleur, and taking up 3mm of your hanger seems pretty shady.
— Tim

Thanks for your question.
― Lennard

Dear Lennard,
One combination of shifter, derailleur, and cassette that seems to work essentially perfectly is to use 11-speed Campagnolo shifters with 9-speed Shimano rear derailleur and cassette. There is actually a 0.1mm difference in the cable pull per gear between the two systems, but if the derailleur is adjusted so that it is centered on the central cog of the cassette, the float in the top jockey wheel is more than enough to take up the 0.4mm difference at either end of the cassette.

I have this combination installed on two bikes, and the shifting works just as well as it did with the original Shimano shifters. I also found that new 11-speed Chorus shifters were pretty much the same price as sellers were asking on eBay for NOS 9-speed Ultegra shifters.
— Nick

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Technical FAQ: Shifting compatibility with different cassettes http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-shifting-compatibility-with-different-cassettes_378952 http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-shifting-compatibility-with-different-cassettes_378952#comments Tue, 21 Jul 2015 19:03:49 +0000 http://velonews.competitor.com/?p=378952

Derailleur compatibility questions? Lennard Zinn has answers. Photo: Caley Fretz | VeloNews.com

Lennard Zinn answers questions about how you can run a mix of different parts and gets a tip on how to help out a weak derailleur.

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Derailleur compatibility questions? Lennard Zinn has answers. Photo: Caley Fretz | VeloNews.com

Dear Lennard,
With all the wide-range cassettes and drivetrains people are setting up, I thought I’d share a good modification I’ve found to put a little more cog into a given derailleur. A thin washer — I get stainless ones from the hardware store for 15 cents — between the hanger and derailleur can add enough clearance for a few more teeth. It moves the shift plane of the parallelogram out a little bit, putting the guide pulley a little lower at any given cog. I figured this out by trying to make a thin hanger work with a normal cassette and a cheap, under-sprung derailleur, but it works as well on a high-end road bike. I fit a 32-tooth cog on a Bianchi Infinito with a short-cage derailleur with no cog-pulley contact, and it helps with the 42-tooth cassette adapters, too. Chain wrap isn’t ideal, but it works, and customers appreciate a $1 solution to a $100 problem.

I hope your readers find this useful.
— Tim

Dear Tim,
That’s a great, creative solution. Thanks for sharing it with us.

By the way, that is a method that I have also used with success on a drivetrain that was sluggish in getting the chain to the smallest cog. The derailleur spring can be too weak to overcome the resistance in the cables with an old or cheap derailleur, or with continuous cable housing from front to rear like on some older, internally-routed frames, or with tandems, or with sharp cable bends in the system. The hardest shift will be to the smallest cog, because in that position, the derailleur spring is closest to its relaxed state (except with a Shimano Rapid Rise or low-normal rear derailleur).

By putting a spacer between the derailleur hanger and the derailleur, you effectively tighten the spring in every position.
― Lennard

Dear Lennard,
In the last Tech FAQ, a reader asked about using Campy shifters with a Shimano cassette. It does work — and well. I use it on my CX bike. I am using Campy 11-speed shifters with an older XTR Rapid Rise rear derailleur that has 10-speed pulleys. You have to clamp the cable a bit differently but it works well … you get 10 speeds. The reader didn’t specify (or I missed it) if he was trying to use the Campy rear derailleur or not.
— JC

Dear JC,
I made the possibly erroneous assumption that Reggie was using a Campy rear derailleur with the Campy shifters. But now when I re-read the question, I see that, as you stated, he doesn’t actually specify. Interesting how I can read something like that and picture in my mind exactly the setup I think that he has, and then on later review, I discover that the letter never mentioned some of the parts that I pictured so clearly in my mind … Another reminder to read more carefully without preconceptions!

I assume you’re doing the “Hubbub Shimagnolo” conversion by clamping the derailleur cable farther back around the cable-fixing bolt on your XTR 8- or 9-speed derailleur, rather than in its standard groove below the bolt. This decreases the derailleur movement with each click of the shifter.

The 11-speed Campagnolo Ergo Power shifter pulls 2.6mm of cable with each shift click, and the shift-actuation ratio of a (non-Dura-Ace) 6-, 7-, 8-, or 9-speed Shimano rear derailleur is 1.7. Multiplied together, that gives a lateral derailleur movement of 4.42mm for each click. However, the cog pitch of a Shimano 10-speed cassette is 3.95mm (center-center distance between adjacent cogs), so you need the derailleur to move less far with each click. (By contrast, a Shimano 10-speed road STI shifter pulls 2.3mm of cable with each shift click.)

As it says here about the Hubbub conversion on Sheldon Brown, “To get the indexing to match the sprocket spacing, you will have to check and readjust the place where the cable attaches.”

Over time, non-standard cable-clamping locations tend to fray and break the cable strands, so check for that frequently so you don’t end up far from home with a broken cable.

That’s cool you’re using a Rapid Rise rear derailleur; I’ve never seen a setup with a Campy shifter where operating the shift paddle moves the derailleur to a smaller cog, rather than to a larger one!
― Lennard

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Technical FAQ: Specialized’s aero claims, mixing parts, and more http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-specializeds-aero-claims-mixing-parts-and-more_376904 http://velonews.competitor.com/2015/07/bikes-and-tech/technical-faq/technical-faq-specializeds-aero-claims-mixing-parts-and-more_376904#comments Tue, 07 Jul 2015 14:19:37 +0000 http://velonews.competitor.com/?p=376904

Specialized's new Venge was built with aerodynamics in mind. Photo: Tim De Waele | TDWsport.com

This week, Lennard Zinn addresses reader questions about, among other topics, Specialized's recent time-saving claims

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Specialized's new Venge was built with aerodynamics in mind. Photo: Tim De Waele | TDWsport.com

Specialized time savings for real?

Dear Lennard,
I’m fascinated by the 5-minute claims by Specialized. However, the article states that Specialized just added up the time savings for each piece of equipment and did not take into account how the parts interact as a whole. Is it really that simple or do the mathematics change when each piece is combined?
— Ben

Answer from Specialized:

That’s a good question. Simply put, the five things that we broke the 5-minute claim into are more or less aerodynamically independent and can be added (keep in mind that the 5-min claim was a bit conservative to take into account some differing interactions depending on the specific rider). To summarize:

— Frame, wheels, and tires: These definitely cannot be split apart and their individual aero gains summed due to interaction effects. As a result, we’ve lumped the total bike system aero gain into one number (keep in mind, the tire in this case represents the aero benefit of the tire, not the rolling resistance).

— SW Turbo tires: This is a pure rolling resistance number so it is independent of any aero claims and can be added in terms of time saved.

— Skinsuit, helmet, and shoes: These are all largely different and separated regions of the body so a more efficient solution in one piece doesn’t necessarily impact the others. For example, using a faster helmet doesn’t change the aerodynamic benefit of a skinsuit (except in fringe cases like a TT helmet in a low position shielding a flapping jersey).

So yes, where the aero interaction is critical, we took it into account by lumping into one system and time saved number (frame/wheels/tires) and for everything else that acts independently, you can sum the time savings.
— Dr. Chris Yu
Aero & Racing R&D Lead
Specialized Bicycle Components

Dear Lennard,
Stage 6 of the 2015 Tour de Suisse was 237km. If Specialized’s claims are true, then Sagan and Cavendish should have arrived in Bienne 32:47 ahead of everyone else.
— Paul

Dear Paul,
Actually, it doesn’t apply when riding in a peloton. If it were a 237km individual time trial ridden on road bikes, then Specialized’s claims could be tested, but even then, it would only apply to the individual. In other words, if Specialized’s claims were true, then Sagan and Cavendish should have arrived in the 237km ITT to Bienne 32:47 ahead of when they would have arrived on a Specialized Tarmac or similar road bike, while wearing their old shoes, standard bib shorts and jersey, road helmet, and while riding industry-standard racing tires. So they would have each had to ride that 237km ITT twice! That’s not something you’re likely to see them do.
― Lennard

Mixing drivetrain parts

Dear Lennard,
Can you use a Campagnolo Centaur 10-speed STI shifter with 9-speed cogs? Will this be OK, or will I have problems with the drivetrain in the long run? Will the index shifting be precise, or will it not shift, or will it have a hard time shifting? Do I need to change the cogs to a 10-speed, and if I need to will any 10-speed cogs work?
— Reggie

Dear Reggie,
That won’t work. You’ll have to get a 10-speed cogset, and it must be Campagnolo. Shimano, SRAM, etc. cogs won’t work in other than a class-B performance with skipping at some place in the range, because the spacing of their 10-speed cogs is narrower than Campy’s.

BTW, “STI” stands for Shimano Total Integration, so it is not a universal term for a brake/shift lever. “Dual-control lever” or “brifter” are generic terms for that. Campagnolo’s version is called “Ergo Power,” and SRAM’s is called “Double Tap.”
― Lennard

Dear Lennard,
Will Shimano 105 brake calipers work with Rival 22 levers?
— Tim

Dear Tim,
They will work, but in a class-B way. The SRAM lever has too much leverage and too little cable pull for that brake to work ideally, assuming you’re talking about a current Shimano 105 brake caliper. You could end up on your nose if you’re not careful when pulling the front brake hard.

However, that SRAM lever will work fine with an old (at least five or so years old) Shimano 105 brake caliper meant for a Shimano 105 lever with the shift cables exposed, sticking out of the sides of the levers. Shimano increased the cable pull of the lever and the leverage of the caliper when it went to the lever style with which the shift cable is concealed under the handlebar tape.
― Lennard

Dear Lennard,
Do you know if I can use SRAM RED/Force or Rival 22 shifters with my existing Campy Record Skeleton brake calipers? I wasn’t sure if the cable pull would allow them to be compatible.
— Chris

Dear Chris,
Yes, those will work fine together.
― Lennard

More on internal cable routing

Dear Lennard,
In response to Abdul’s internal cable routing dilemma, I have a cheap method that has worked for me several times when trying to run internal cables. First you will need to find some thin, flexible, moderately strong string (kite string works great) some masking tape, and a vacuum with a hose. I use the tape to tape off all holes on the frame except the two that the cable will enter and exit.  Then, take a length of string that is longer than the path the cable will run through and feed it into the smallest hole and then tape the other end to the frame near the entrance point. Now take the vacuum and use your hands to create a reasonable seal at the larger hole and suck the string out that end of the cable path. It sounds a bit goofy but it has worked perfectly with two different frames and along different paths. The final step for me is to then tape the string to some Teflon internal cable housing and then carefully pull the housing back through the path. I then run the cable through the housing and then, if desired, you can pull the housing out or just trim it a bit and leave it in place. This also works great with internally routed handlebars. I hope this helps.
— Steve

Dear Steve,
Cool method!
― Lennard

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Technical FAQ: Internal cable routing and more http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/technical-faq-internal-cable-routing-and-more_375632 http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/technical-faq-internal-cable-routing-and-more_375632#comments Tue, 30 Jun 2015 14:49:37 +0000 http://velonews.competitor.com/?p=375632

Internal cable routing on reader Abdul's Boardman Air Pro. Photo: Abdul

This week, Lennard Zinn addresses reader questions about routing cables, mixing drivetrain parts, and more

The post Technical FAQ: Internal cable routing and more appeared first on VeloNews.com.

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Internal cable routing on reader Abdul's Boardman Air Pro. Photo: Abdul

Routing cables

Dear Lennard,
I’ve been having serious issues with my Boardman Air Pro front mech cable replacement. I can’t feed the cable through whatsoever. I have the whole frame stripped down and the bottom bracket bearings out, thinking I may be able to see the cable getting stuck. I’ve had no luck. Here are some pics to clarify what I’m doing (above).

It feels almost impossible to route a cable through a 45-degree bend (top tube to down tube). I really need help from you, as I can’t rebuild my bike knowing I can’t feed a cable through.
— Abdul

Dear Abdul,
Yes, that looks like a tough challenge. I’ll bet you could do it with the Park IR-1 tool, though. You at least stand the best possible chance of getting your cable through if you use that tool.
― Lennard

Follow-up to a foot problem

Dear Lennard,
This article caught my eye immediately because the first photo looks just like what I see looking down. My right foot is also rotated 20 degrees out. I had knee pains starting a few months after I started riding. I was able to come up with a solution that’s worked for six years now, so I thought I’d share it just in case it could work for Colin.

I use Look Keo pedals with grey (4.5-degree) cleats on my circa 2009 Specialized shoes. My left foot is set up normally. My right foot has the cleat slid toward the crank to get my heel as far from the crank arm as possible. I have the cleat twisted where the 4.5-degree float has my shoe turned as much as it can without striking the crank arm while clipped in. This set up leaves my foot still twisted, but not as far out as standing natural (10 degrees). I rode my first few months like this, but as I got faster, I started to get knee pain. I noticed my foot would wobble through pedal strokes, because the outside of my foot has more pressure and the ball of the foot would actually lift up during the full crank revolution, then contact again on the down stroke. I used tape on the underside of the shoe insert. I layered it thicker under the ball of the foot and tapered it across with none on the outside (slowly adding a roll to my foot). I started conservative and then added more layers after rides until I felt no side-to-side rocking of my foot in my shoe. Once I eliminated the odd wobbling of my foot, my knee hasn’t experience pain since.

This solution worked out for me. I never tried to match the amount of twist of my foot, instead working with the max amount of twist I could have on the bike. If I were to stand with my feet crank-width apart and both pointed straight, my right foot feels like I’m going to roll my ankle over the outside of my foot. If I move my right foot to how I set it up on the bike, it is still rolled, but not nearly as much. My shoe shimming just accounts for this roll and keeps the loads on my knee more even (inside vs. outside).

I hope this might help him. I’m 32 now and still have no problems, and it served me well while collegiate racing in grad school four years ago. I didn’t know it was that uncommon of a condition. I’m planning on a full bike sitting session when I get a new bike and pair of shoes. I figured the fitter would have seen this loads of times and chuckled about my use of tape as shims.
— James

Dear James,
Thanks for that. I don’t think that much rotation is very common, but hopefully you will indeed go to a fitter who has experience in correcting for it.
― Lennard

Mixing parts

Dear Lennard,
I have a ’cross bike that I ran single ring in front and 11-speed rear with a SRAM 2014 CX1 RD and Force 22 shifters. The RD can handle an 11-32, but that is as wide as it goes.

I want to use the bike for gravel fondos with lots of climbing and road, so I want to run a double up front to widen my gear range.

I really like the security of the CX1 RD and am wondering if I can run that with a double up front and if not is there a SRAM MTB RD that has a clutch that will work with 11-speed shifters and cassette? (The cassette and chain are normal 11-speed SRAM — I filed the jockey wheel teeth down on the CX1 so they are no longer high/low).
— Dave

Dear Dave,
SRAM Road and Zipp PR content manager Daniel Lee says, “About the possibility of running two front rings with the Force CX1 / Force 1 1x rear derailleur, the short answer to this is a very definite no, the X Horizon RD will not work with any multi-ring setup. It simply won’t work.”

As for filing the jockey wheel teeth down, that was not necessary, and it would not have been necessary even if you could have used that rear derailleur on a multiple-chainring setup. Indeed, the front chainring teeth on a double would not work being fat-thin-fat, because the chain would be moving off of one ring and onto another and may not sync with the right space in the chain. But the chain never leaves the jockey wheels, so the fat-thin-fat teeth could not get out of sync with the chain, once they’ve been engaged correctly in the chain.
― Lennard

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The new Giant TCR, wheels, and saddles http://velonews.competitor.com/2015/06/news/the-new-giant-tcr-wheels-and-saddles_375359 http://velonews.competitor.com/2015/06/news/the-new-giant-tcr-wheels-and-saddles_375359#comments Sat, 27 Jun 2015 22:01:01 +0000 http://velonews.competitor.com/?p=375359

Slim seat stays, fork legs, seat mast, and rear top tube section improve ride compliance of the TCR Advanced SL while decreasing its weight. Photo: Giant Bicycles

Giant continues the evolution of its TCR bike line, which has dropped weight and is now stiffer. New wheels and saddles also announced

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Slim seat stays, fork legs, seat mast, and rear top tube section improve ride compliance of the TCR Advanced SL while decreasing its weight. Photo: Giant Bicycles

MALLORCA, Spain (VN) — Giant Bicycles’ capabilities are legendary, but it may not appear on your short list of innovative bike companies. However, consider the Giant TCR. When this “compact” frame with long, super-deep aero seatpost first appeared in 1997 under the ONCE team, can you recall how shocked you were? Its sloping top tube was so radical at the time that the UCI, in its infinite wisdom, initially banned it. Its look was strange compared to the level top tubes and short seatposts we had always accepted as being de rigueur for a road bike, but perhaps even more revolutionary is that it was the first sub-one-kilogram racing frame on the market — and that was in aluminum!

TCR was a do-it-all bike intended for climbing, sprinting, and time trialing, and, indeed, ONCE used the same bike for all of those things. The steeply-sloping top tube looked particularly radical when coupled with aero bars and a disc wheel under Igor Gonzalez de Galdeano in time trials.

A few years later, when the TCR appeared with an integrated seat mast, it also literally broke the mold of what other manufacturers were doing. Perhaps you remember that ONCE director sportif Manolo Saiz, after losing the Giant sponsorship of the team, now sponsored by Liberty Seguros, to Telekom, pressured new bike sponsor BH to also give him bikes with an integrated seat mast so that his stallions would not be at a disadvantage to Jan Ullrich.

The 2016 TCR

For 2016, Giant has an all-new TCR Advanced SL (with an integrated seat mast), TCR Advanced Pro, and TCR Advanced. The Advanced SL is considered its versatile GC bike, although don’t expect to see it used in time trials by Giant-Alpecin riders. Giant engineers have smoothed many of the sharp edges of the design that collected resin and fabric, slimmed some sections, trimmed the fat off of the seat mast cap, and added hollow carbon dropouts, shaving off 181 grams — a full 12 percent of its weight.

At the same time, TCR claims best-in-class pedaling stiffness/weight ratio for the frame, frameset-plus-wheelset pedaling stiffness/weight ratio when coupled with Giant’s new SLR 0 carbon wheels, torsional stiffness including the fork, and one of the lightest frame weights. And indeed, when climbing the mountains of Mallorca this week on it and descending the tight, tortuous switchbacks down their flanks, the TCR Advanced Pro jumped at the slightest application of pedaling force and kept the wheels tracking through the tightest turns.

VeloNews spotted this new frame at the Amgen Tour of California, ridden by Giant-Alpecin’s Lawson Craddock.

Giant claims to be the only company in the bike industry to build entire bikes starting from the fibers, particularly now that BMC seems to have abandoned its Impec robotic carbon-fiber knitting project. Giant buys the raw carbon fibers, but it takes it the whole way from there. It makes the fabrics and impregnates them with its own proprietary resins, creating the pre-preg fabric on-site that other manufacturers must buy from other suppliers. It uses these fabrics not only in its frames, but also in its rims and saddles, as well as other components.

Over the years, our eyes have not only become accustomed to sloping top tubes, but also to huge tube dimensions on frames, but striking features about the new TCR include super svelte fork legs, seat stays, rear top tube section, and seat mast/seatpost. Clearly, weight is saved through making these parts very slim, and according to Giant’s test results, torsional rigidity is not sacrificed in the process. The lean, aero-shaped integrated seat mast on the TCR Advanced SL and seatpost on the Advanced Pro and Advanced is designed to give more fore-aft compliance.

Raising the integrated lower headset bearing inside the oversized head tube so it is more in-line with the huge Megadrive square-cross-section down tube stiffens the steering. Huge dimensions of the tubes meeting the 86.5mm-wide press-fit bottom bracket shell further increase torsional and pedaling stiffness.

The TCR will be available in the USA starting in August. Prices range from $9,000 for the TCR Advanced SL with Dura-Ace Di2 and SLR 0 carbon wheelset to $1,700 for the TCR Advanced 3 complete bike.

The Wheels

The carbon rims on the Giant SLR 0 and SLR 1 come in 30mm and 55mm deep versions that have a 23mm outer width and 17mm tubeless-compatible inner width. The glass transition temperature (Tg) of the resin is 245C, much higher than the industry standard. Giant claims to have performed brake-heating tests against Zipp and Reynolds rims and that the Giant SLR 0/1 clincher rim with SLR pads and 100psi tire lasted without any damage through two 15-minute tests for a total absorbed braking energy of 75Wh. Giant claims that the Zipp with Tangente pads also survived both 15-minute periods but that surface bubbling on the brake surface appeared, while Reynolds rims with Cryo-Blu pads failed during the first 15-minute test run.

Giant further claims that it came out on top when comparing both wet and dry braking performance of these same three rims and pads plus a Bontrager rim with Carbon Stop Cork pads. There was nary a hint of rain in two days of riding on hot days in Mallorca, but dry braking on the many serpentine switchbacks was positive and squeal-free for me.

Dynamic Balanced Lacing (DBL) is the term Giant has coined for its system of having the drive-side tension on the pushing spokes higher than that of the pulling spokes in the static state. This is accomplished by anchoring the heads of the pushing spokes lower in the hub flange than the pushing spokes. When the chain twists the freehub forward, it tightens the pulling spokes and loosens the pushing spokes, thus evening out the tension on all drive-side spokes (or dynamically balancing the tension). This is intended to increase the durability of the wheel, since uneven spoke tension is well known to decrease a wheel’s life.

The anchor points of all drive-side spokes are also pushed further outboard to better balance the left/right spoke tension while still providing the room required for 11 cogs and the derailleur cage when using the largest cog. Having 21 rear spokes with 14 on the drive side and seven (radially-laced) on the non-drive side is also supposed to even out spoke tension between the two sides. The front has 16 radial spokes.

The rims and lacing systems are the same on both SLR 0 and SLR 1 wheels, but the SLR 1 is $1,000/set cheaper ($1,300 vs. $2,300/pr.). This is accomplished by dropping the SLR 0’s DT Swiss star-ratchet freehub system and Aerolite/Aerocomp bladed spokes in favor of the SLR 1’s standard freehub pawl system and Sapim Race/Laser round, butted spokes. Bike mechanics will not be overjoyed about the hidden spoke nipples, but wheel product manager Jeff Schneider insists that DBL results in such balanced wheels that the wheels will be much less likely to come out of true than other wheels.

SLR 0 wheels are listed as 1331 grams/pair 30mm-deep rims, which Giant says is best in class. It also claims transmission stiffness test results of a 65kg dynamic pedaling load on a 175mm crank in a 39x25t gear showing the SLR 0 to have not only the highest stiffness, but also the highest stiffness-to-weight when compared to the Zipp 202 Firecrest, Bontrager Aeolus 3 D3, Roval Rapide CLX 40, and ENVE Smart 3.4. It also claims higher lateral stiffness than any of those wheels, measured by side-loading the rim in the static state.

The Saddles

Giant’s new Contact SLR and Contact SL saddles feature “Particle Flow Technology;” rather than gel-filled sections, the Contact saddles have beads in two compartments that move with the rider’s structure to distribute pressure over a wider area without pushing completely through a gel pocket. Its other unique feature is a fitting system that is determined while riding, rather than while sitting on a static memory foam pad or performing body flexibility tests.

During the dynamic saddle impression evaluation, the rider pedals for at least two minutes on Giant’s fitting saddle after it has been installed on the bike at exactly the same height as the rider’s existing saddle. Underneath a clear, opaque-gel-filled top layer, the fitting saddle has four demarcated zones colored either blue, white, pink or red. After the rider has pedaled for a couple of minutes with thin shorts and no chamois pad, he or she will have moved the opaque gel out of the way enough that some of the colored zones will be visible. Asymmetries in saddle contact pressure as well as side-to-side and fore-aft pressure distribution can be immediately identified thanks to the brightly-colored areas revealed. Referring to a chart, the retailer can select the proper Forward, Neutral, or Upright saddle shape.

With carbon-filled base and carbon rails, the 180g Contact SLR sells for $225, while the 210g Contact SL with tubular stainless steel rails sells for $110.

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Can Specialized save you five minutes over 40km? http://velonews.competitor.com/2015/06/bikes-and-tech/can-specialized-save-you-five-minutes-over-40km_374892 http://velonews.competitor.com/2015/06/bikes-and-tech/can-specialized-save-you-five-minutes-over-40km_374892#comments Tue, 23 Jun 2015 08:05:44 +0000 http://velonews.competitor.com/?p=374892

test Test test Test

Lennard Zinn examines the possibility that Specialized can make any rider five minutes faster with its new line of aero products

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test Test test Test

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Technical FAQ: A perplexing foot problem http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/technical-faq-a-perplexing-foot-problem_373053 http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/technical-faq-a-perplexing-foot-problem_373053#comments Tue, 09 Jun 2015 15:46:49 +0000 http://velonews.competitor.com/?p=373053

Colin was still sitting twisted. Because his right foot is so twisted, the heel ends up about 1cm in front of where the left foot's heel does if both cleats are in the same position. Photo: Colin McKay

One reader reaches out to Lennard Zinn for help with a twisted foot that has caused him knee pain

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Colin was still sitting twisted. Because his right foot is so twisted, the heel ends up about 1cm in front of where the left foot's heel does if both cleats are in the same position. Photo: Colin McKay

Dear Lennard,
Though my left foot is relatively normal, my right foot points toe-out at a roughly 20-degree angle when my knee is pointing straight. [The first photo above shows] how my foot lands naturally when walking.

[The next photo displays] the position my foot naturally assumes (as in, when using flat pedals) while riding a bike.

If you’ve never heard of this problem, a quick Google search will reveal that, while it’s pretty uncommon, it’s not totally unheard of. I’m telling you about this because I want my battle to find solutions to be available as a path for others to follow.

A note on my personal backstory: I rode at a decent level for a couple years in my early 20s without too much trouble, though I had this problem the whole time. A top rider on club rides, 100+ kms every Saturday, at least another 100km over the course of the week, every week. My foot has been twisted at this angle since birth, but somehow I was able to ride sitting crooked on the saddle and with a much-too-low saddle height, and this accommodated me, though I got knee pain and hamstring injuries every so often that other riders didn’t. I did a lot of yoga and stretching and became extremely injury paranoid over time, which eventually led me to start seriously looking at bike fit — specifically the problem of my feet. I should note that the whole time I was battling this, I was somehow riding at least 150km a week, and just getting injured all the time without fully understanding how far off my bike fit really was. The changes I made I figured out and implemented very gradually as my understanding grew, and feedback from my body became more clear (it sounds weird but I honestly didn’t realize how big of a problem my twisted foot was for a long time, probably because being 15 degrees from ideal feels about the same as being 10 degrees from ideal).

I started out riding Shimano SPD-SL pedals, so I only had 6 degrees of float with the yellow cleats, although of course you can angle the cleat on the shoe — but only so much. The first barrier I came up against was the position of the cleat bolts on my shoes: Specialized shoes have fixed cleat bolts, which only allow for about 9 degrees of twist, even after you include the float from the shoe.

It’s important to note that I tried Speedplay at this point as well, because everyone says that they’re the masters of float and adjustability. But here’s the problem — Speedplay cleats, with or without the adapter plate, CANNOT be rotated. All you have rotationally is the 15 degrees of float on the pedals — but that’s only 7.5 degrees heel-in, and 7.5 degrees heel-out. More than enough for a normal person, but nowhere near enough for me.

The solution to cleat-bolt barrier was to buy shoes with moving cleat bolts. The best on the market right now are Shimano, which allow 11mm of forward-backward cleat movement, with each bolt hole operating independently.

But you may also notice from the above picture when I was at 9 degrees that I was also at the limit of crankarm and chainstay clearance. Any solution to a large amount of toe-out necessarily must include pedal extenders. For myself, I bought Kneesavers from kneesaver.net; this is an indispensable product for dealing with this condition. The website sells 20mm titanium and 25mm, 30mm, or more in steel.

The combination of the Shimano shoes for the cleat bolts and 20mm Kneesavers pedal extenders for the clearance took me to 15 degrees of twist (including the float on the Shimano cleat).

Remember though, I needed 20 degrees. I could get as much clearance as I needed with the Kneesavers, so the problem was getting enough cleat twist out of my shoes. So out came the drill.

But here’s where things get interesting: 3-bolt LOOK style shoes are convex, and 3-bolt LOOK style cleats are concave. They fit together up to a certain amount of rotational twist, but after that the curved triangle shape ceases to be flush. That point just happens to be 15 degrees.

Anyone who needs to go beyond 15 degrees of toe-out rotation will have to get truly innovative. 3-bolt LOOK style pedals go out the window and all that’s left is Speedplay, because they’re flat and will thus sit flush at any angle you need if you’re also using Speedplay-specific shoes with flat carbon soles.

But … they only mount onto these shoes facing straight forward, as noted above.

So here’s what I did: drill a hole in the middle of the carbon shoes, widen two of the existing slots, insert M5 wood T-nuts, and bolt the flat extender base plate (without shims) to the flat carbon sole at the angle that I needed, using the slots intended for connecting to a 3-bolt shoe. Then, bolt the flat Speedplay Zero cleat to the extender base plate, and voila.

Amazingly, I needed much, much more than just the 20mm Kneesaver to get where I needed. In fact, for 20 degrees of rotation, I needed the 65mm Speedplay Zero spindle (12mm longer than normal), screwed into a 25mm Kneesaver, for an astounding +37mm of extension.

BUT IT WORKED. IT GOT MY FOOT WHERE IT NEEDED TO BE, AND MY KNEE WAS HAPPY FOR THE FIRST TIME ON A ROAD BIKE!

Happy ending?

Not yet. After a few rides in my new position, something weird became apparent: I was still sitting twisted. It didn’t take too much searching to find the reason. Because my right foot is so twisted, the heel ends up about 1cm in front of where the left foot’s heel does if both cleats are in the same position.

So my story ends with a question, that only a professional can answer for me. Should I move the LEFT foot’s cleat 1cm back … to move the left heel 1cm forward … so it’s on the same place as the right heel?
— Colin

Dear Colin,
I sent your photos and description to top bike fitters Charles Van Atta of the Boulder Center for Sports Medicine and Katrina (Kit) Vogel, MS, DPT, Director of Clinical Education for BikeFit.com. Here is what they wrote:

Van Atta:

I wonder if he really needed to go for the entire 20-degree rotation. As he switched from the very flexible “flat pedal” shoes to a more supportive road shoe, wedging and arch support might have taken the place of some of his need for external rotation of the foot. If the rotation is the best way to get the knee tracking straight then I think moving the left foot forward would be a sensible approach to even out knee extension at the bottom of the stroke.
— Charles A. Van Atta
Cycling Biomechanist
Boulder Center for Sports Medicine

Vogel:

Moving the left foot forward may be a good option but it depends on the mechanics of both lower extremities and the lumbo-pelvic mechanics. He doesn’t really mention exactly **how** he was seated on the saddle. It sounds like he ended up sitting to the right of saddle midline. His documentation of his case is very detailed, but I need more information to give an informed answer, especially regarding the mechanics of his other leg.

1) Regarding his body position:
a. Knee and shoulder angle? FA?
b. What are the mechanics of right and left lower extremities from the front?
c. Pelvic & lumbar mechanics from the back?

2) Regarding his body architecture:
a. Is the right leg position driven from femoral retroversion and tibial external torsion? Club foot?
b. What is the architecture of the left LE?
c. Has a LLD been ruled out?
d. How much of a forefoot/rearfoot varus is present? If any?

3) What other injuries has he had that may be affecting his position?

4) Which Speedplay pedals did he use?

Answers to these questions will give me the information I need to more fully answer the rider’s question.
— Kit

Dear Lennard,
Thank you so much for taking such an interest in my case. It’s been a real struggle trying to solve this, alone, from Japan.

First an update, unfortunately a sad one. The enormous amount of spindle spacing, which allowed me to have heel clearance and accommodate my twisted leg, has been giving me medial knee pain. Toward the end of rides my knee starts going way out from the top tube — I suspect it’s trying to push down directly onto the pedal, but because of the spacers, this presents a big problem Q-factor-wise. I’ve switched back to +4mm Dura Ace pedals with a 20mm spacer, in search of a compromise between twistedness-accommodation and Q-factor problems.

Now for Katrina Vogel`s questions. Some of my answers are going to be unsatisfactory … I live and work in Japan, currently and for the duration of this battle. Japanese bike fitters and medical professionals have been largely unhelpful; the language barrier contributes to this.

1) Regarding his body position:
a. Knee and shoulder angle? FA?

Within the normal range. 143-degree knee angle last I checked.
b. What are the mechanics of right and left lower extremities from the front?
Unsure what this means …
c. Pelvic & lumbar mechanics from the back?
Probably what would be termed “excessive” anterior pelvic tilt (desk job). I’ve been fighting it for over a year with glute bridges/ab work/psoas stretching, but sitting 40 hours a week = limited success …

2) Regarding his body architecture:
a. Is the right leg position driven from femoral retroversion and tibial external torsion? Club foot?

Tibial external torsion. I’m not so sure what femoral retroversion means, but looking at my leg it’s clear that the twist is at the tibia. Club foot is not present.
b. What is the architecture of the left LE?
Normal is my best guess …
c. Has a LLD been ruled out?
Yes, LLD ruled out by Makito Fushimi of Sun Merit Bike Fit Studios in Japan. He’s affiliated with Bikefit.
d. How much of a forefoot/rearfoot varus is present? If any?
At least some, on both feet. I’ve ridden with various amounts of wedging, and it unquestionably feels better pressure/varus collapse-wise but doesn’t seem to affect where my heel wants to be on the pedal. Currently using three wedges per foot.

3) What other injuries has he had that may be affecting his position?
Nothing other than what I lightly mentioned as the twist being present “from birth.” The longer version is I was born toed-in, and a specialist twisted my feet and casted them toed-out. Turns out this was later disowned by the medical community as unnecessary, as excessive internal rotation of babies’ feet corrects itself spontaneously over time, but nobody knew this in 1986, so now my right tibia has this problem.

4) Which Speedplay pedals did he use?
Zeros

Finally, a question of my own. I don’t have IT band pain currently, but I know my IT band is tight. Is it possible this is contributing to the tibial external torsion? I can’t understand how I was so strong in Canada, riding so twisted, and now it’s such a terrible problem. Perhaps the twistedness increased?
— Colin

Dear Colin,
We unfortunately have not yet been able to solve your problem at this great distance. It is such an interesting case (and a tragic one, given that it probably never would have happened if that doctor had not tried to “fix” your legs when you were a baby), that I thought others could learn a lot from it and could perhaps contribute to the solution.

My experience with myself and many other riders is that the body can handle an astounding amount of asymmetry in bike position when young, but as you age, after having pedaled your legs around millions of times over decades in an asymmetrical position, the body’s adaptation to those repeated stresses becomes an issue in and of itself. There is wear and tear on the articular cartilage in joints that are rotated in ways they were not designed for. Arthritic growth sometimes occurs in response to this high level of wear of the joints. Fascia becomes tight in an effort to reduce the muscle strain required to hold the body parts in positions that the skeleton cannot support alone. Blood flow and ability of the muscles to move are both restricted by the tighter fascia, which can lead to tighter fascia yet to compensate for weakened muscles. The whole process is cyclical, and it leads to ever more restriction. And yes, it’s possible that the tighter IT band, which attaches to the tibia and is a fibrous extension of the fascia of the thigh muscles, could be increasing the external torsion of the tibia.

One can hope that a solution can be found that supports your body in a functionally effective pedaling position that allows your legs to move and be supported properly with minimal wear. In all cases, since we are all asymmetrical, compromises must be made, and that is particularly true in your case. Given that pedaling is a planar movement and your knee and forefoot must go way out of that plane, it may not be a solvable problem. Your forefoot must be so far away from the plane of the bike to not tear up your ankle on the crank that your knee will have to stick way out, and that will cause problems up and down the chain, including up into your back.

One possible piece of equipment that perhaps could ease your problems is the Nikola pedal. The pedal moves outward by 25mm as it goes down, so you might be able to have your knee and foot and ankle further in at the top of the stroke than you do now. By moving outward on the downstroke, the pedal’s movement may allow your ankle to clear the crank as it passes it. But since you don’t need the ankle clearance at the top of the stroke, why not allow your foot to come inward up there? Perhaps that would reduce the medial knee strain.

I’m also hopeful that somebody reading this may offer a piece or two to the puzzle that has the potential to be a solution for you. I can only imagine how hard it must be for you to not be able to find a way to ride your bike without pain.
― Lennard

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Magura press camp: Riding e-MTBs, casual gear, and more http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/magura-press-camp-riding-e-mtbs-casual-gear-and-more_372584 http://velonews.competitor.com/2015/06/bikes-and-tech/technical-faq/magura-press-camp-riding-e-mtbs-casual-gear-and-more_372584#comments Wed, 03 Jun 2015 15:22:19 +0000 http://velonews.competitor.com/?p=372584

A full-suspension e-bike is a heavy beast, but it may be able to take you places you couldn’t go without pushing your bike. Photo: Lennard Zinn | VeloNews.com

At Magura's annual press camp, Lennard Zinn discovers he is a fan of e-bikes, takes a shine to casual riding clothes, and more

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A full-suspension e-bike is a heavy beast, but it may be able to take you places you couldn’t go without pushing your bike. Photo: Lennard Zinn | VeloNews.com

SEDONA, Arizona (VN) — Magura’s annual press camp in Sedona added Club Ride to the Magura, SKS, Uvex, Vredestein, and, for the second year, Bosch equipment lined up for testing on steep and rocky trails.

Bosch e-bikes

After the second day in a row of long, hard morning mountain bike rides, I rode down a 10-kilometer descent to go swimming at the trail crossing of Oak Creek with about 10 other people from the press camp, and all of us rode Bosch-equipped e-bikes. After that, my opinion of owning an e-bike changed; I could definitely see it as being a useful part of the bike quiver of an avid rider, namely for recovery rides.

After a long ride on a hot day, it’s enjoyable and it hastens recovery to take an easy spin and sit in cold water in a creek. But without flat roads, that’s not easily done, and there is no way I would have felt up to climbing entirely on my own power in bright sun and 90-degree heat back out of that 10km descent, much of it on dirt; it would have been counterproductive for recovery as well as mental attitude.

But with the e-bike providing triple our power (in Turbo mode, the highest setting), former world and national MTB XC champion Ruthie Matthes and I had a nice, conversational recovery spin up the hill after cooling our legs in the creek. And without electric-motor assist, there is no way we could have been roosting on fat bikes in a dirt parking lot with the front brake locked out, spinning out the huge rear tire!

It can be an amazing feeling to ride something like a Felt LEBOWSKe e-fat bike somewhere that would be impossible to go with human power alone because of the difficulty of maintaining momentum due to insufficient traction, steep topography, and obstacles.

The Bosch system has no throttle; it only assists the rider when he or she is pedaling. It has five mode settings: Off, Eco (50-100-mile range), Tour, Sport, and Turbo (19-40-mile range), depending on how much assistance is desired; it supplies 300 percent of the rider’s power output on Turbo. The PowerPack 400 battery recharges completely in three hours, 1.5 hours for a half charge, and two hours to gain an 80-percent charge.

Bosch-equipped e-bikes have either standard shifters or one of three versions of “eShift,” namely: cadence-based automatic shifting with a NuVinci continuously-variable-transmission rear hub; Shimano Di2 internal-gear hub with an up/down shift suggestion screen and automatic throttling back of the motor whenever a shift button is pressed; and speed-based automatic shift of a SRAM internal-gear 3-speed hub with a standard SRAM X9 derailleur, cassette, and trigger shifter on top of it.

While e-bikes have traditionally been seen as limited to bike commuting, e-mountain bikes and e-fat bikes are rapidly changing that perception. Bosch has promoted some of the world’s first e-mountain bike races, including the one at the Riva del Garda bike festival.

In addition to its use for recovery rides, passionate cyclists may want an e-bike around in order to increase enjoyment of riding with an otherwise slower spouse, child, or visiting guest. Or, an e-bike can make it possible for a rider who has slowed down due to age or injury to ride with faster people. Don’t think road rides, though, since most e-bikes have a legally-mandated governor that shuts off the motor at under 20mph; think lower-speed riding like on fat bikes, mountain bikes, and commuting/town bikes.

In addition to brands like Haibike and Lapierre, with whom Bosch has partnered for some time, some of the world’s strongest bike brands will offer Bosch-motor-assist bikes in the U.S. next year, including Trek, Cannondale, Scott, KTM, Felt, BH, and Cube (in Canada).

Bosch is a particularly strong company to be playing in the e-bike arena, with its massive size, global reach, and long history with motors and batteries. The company has over 130 years experience with transportation, from motors that propel vehicles all of the way down to the little motors all over your car that raise and lower windows, run windshield wipers or drive seat and mirror adjustments.

When he was in his 20s in the 1880s, Robert Bosch was already doing pioneering work with electric motors; he improved internal-combustion engines by using a magneto (an alternator, a type of electric motor that produces alternating current) to produce a spark to ignite the mixture of air and fuel. Another critical step toward e-bikes came in the 1920s, when Bosch’s company diversified into a multinational electronics concern, and by launching rechargeable battery packs for power tools in the 1980s, it had everything required for e-bikes.

With not only a huge global company like Bosch in the fray, but also with the entry of Shimano into the e-bike market, e-bikes are destined to grow by leaps and bounds in short order.

Club Ride

Founded in 2008, Sun Valley, Idaho-based Club Ride Apparel claims to be the first bike-clothing company to focus completely on “casual performance.” Whether it was first or not, it has certainly been joined in that by many others who also make practical, full-featured, comfortable clothing for riding that can also be worn in other contexts. For those who have spent decades riding in Lycra, casual riding clothes may hold little appeal, but I’ve recently become a convert.

I do much of my transportation by bike, and, as my business is at my house, I don’t commute. While for many years I’ve shopped and gone to editorial meetings, business meetings, lunch get-togethers, and even evening parties in logo-plastered Lycra, I have to admit that I’m considerably more comfortable in those settings wearing clothes that are more comfortable to sit around in and that look more like board shorts and a button-down shirt.

Since I developed a heart arrhythmia a couple of years ago, I’ve limited my rides in duration and tend to ride ’cross bikes a lot to open more terrain, dirt roads and trails while constrained to a two-hour radius around my house. Aerodynamic efficiency is less important on dirt, and casual cycling clothing works there and offers comfort for off-bike activities.

Club Ride distinguishes four levels of “innerwear” (thin stretch mesh under shorts with a chamois) by how long you’d ride in it. “One-hour ride time” innerwear has a small and thin (3mm) chamois, and the briefs can be colorful and very brief, especially the women’s bikini briefs. They don’t cut it for a couple of hours on a road bike, but if you’re going on a quick ride or have multiple stops on a longer outing, they dry fast and feel fine to spend all afternoon in if you get back to work and are overwhelmed with too much to do to shower or even change.

The “two-hour ride time” inner shorts have an 8mm-thick CoolMax chamois; the three-hour short has an 8mm dual-density perforated pad with gel, longer inseam, and leg grippers, and the four-hour unit is a full mesh bib short with an Italian-made 10mm gel-insert pad. Riding linerless MTB shorts with a bib short underneath is nothing new for mountain biking, but on a hot day, this thin mesh bib short has just as nice of a chamois and is way cooler.

As for the outer clothes, Club Ride’s offerings are made of technical fabrics in logo-less prints with a loose fit and features like back jersey pockets and mesh ventilation panels. Some of its board and cargo shorts come in durable and water-resistant stretch fabrics and are designed to fit over mountain-biking armor.

Magura

On the steep, rocky terrain of Sedona, the Magura brakes and fork on the Intense Carbine 29er I was riding worked flawlessly. Magura has made small incremental changes this year, as opposed to any large product introductions.

All Magura brakes now have top-loading pads, so you can simply remove the pin and pull them out without the need to remove the wheel to get at them. In answer to a common complaint, Magura has added much more reach adjustment to its brake levers. And the mechanical advantage graph for its levers is now linear, so no matter how close or far the lever blade is adjusted relative to the grip, the braking power is the same.

Magura levers may be a bit longer than some other brands, but Magura is unwilling to sacrifice the improved finger sensitivity and modulation they provide for an aesthetic concern about size. It has long used a radial master cylinder as opposed to an axial one (i.e., the piston pushes perpendicular to the bar, not parallel to it) for the same reasons it does this on its motorcycle brakes — namely to provide more room on the bars for other components and to give a more direct power application than do some linkages to axial cylinders.

Its longer levers are part of that power and modulation scheme; small movements of the fingers result in less movement of the piston, and the leverage is higher. There’s a reason why all motorcycle levers have super-long 10-finger blades, and this is it.

SKS

Almost 100 years old, SKS focuses on products to keep people riding more in any weather, and those products are made entirely in Germany. A vast array of full fenders as well as quick-install fenders for every kind of bike, including full-suspension 29ers and fat bikes, make it more appealing to ride in the rain. Carry-along tool kits, Velcro-on bottle cages, and myriad frame pumps eliminate excuses not to ride longer. And a wide selection of floor pumps and electronic pressure gauges, including some for fat bikes, get you out on the bike sooner.

Vredestein

Since 2009, Vredestein has been a part of the $3 billion Apollo Tyres Ltd, the world’s 17th biggest tire manufacturer. Its new reinforced Bobcat tire was developed in Sedona with Magura. It has a full line of road racing, touring, trekking, and MTB tires. Michael Marx, director of Vredestein’s two-wheeled division, is a former German and world champion on track and road.

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Technical FAQ: Drivetrains and tubular tape http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-drivetrains-and-tubular-tape_371735 http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-drivetrains-and-tubular-tape_371735#comments Tue, 26 May 2015 14:31:06 +0000 http://velonews.competitor.com/?p=371735

It's important to replace chains and cassettes when needed. Photo: Caley Fretz | VeloNews.com

Lennard Zinn addresses reader questions pertaining to cog and chain wear, mixing parts, and more

The post Technical FAQ: Drivetrains and tubular tape appeared first on VeloNews.com.

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It's important to replace chains and cassettes when needed. Photo: Caley Fretz | VeloNews.com

Determining chain, cog wear

Dear Lennard,
I’ve been diagnosing a friend’s bike (Specialized Ruby Elite, 105), after I replaced a badly-worn chain (1%). Her LBS said they swapped the chain 1,800 miles ago. The wear I found at 1% says to me that’s more like 6,000-7,000 miles on that chain (Tiagra HG4601, correctly-oriented with writing on the outside, jointing pin in leading hole of plate, no link binding).

Also they say that they replaced the 105 5700 cogset (11-28T) — but the new chain skips under heavy load on all cogs, not just the smallest few.

Looking at the cogs, the teeth have burrs on them commensurate with 6,000-7,000 miles, comparing with a now-retired Tiagra cogset of mine the same age.

Hanger alignment, rear mech alignment, indexing are all fine.

Am I correct in thinking that a very badly worn 11-28T cogset might skip on the larger cogs as well as the smaller ones? I’m used to seeing skipping on smaller ones due to the reduced diameter/fewer links engaged, this is the first time I’ve seen skipping on all of them.

And is there a tool that can accurately gauge cogset wear?
— Mike

Dear Mike,
Yes, a badly worn chain can cause any one of the cogs to become so badly worn that it slips. It doesn’t matter how big the cog is; what matters is how much torque is applied to it for how long.

To understand why that is, consider a worn, elongated chain running over a cog. Since the spacing between pins is greater than it is supposed to be, it is also greater than the spacing between valleys on a new cog. So when the rider is pedaling, the only chain roller that is applying force on the cogs is the one at the top of the cog; the other rollers are not pressed against their teeth because of the chain’s elongation. So, the fact that it has a lot of teeth on it does not protect a large cog from the damage more than a small cog. The chain, if it doesn’t skip off of that top tooth, will mash out the trailing flank of that top tooth to effectively move it further away from the next tooth coming up behind it. And once this reshaping of the cog progresses enough, a new chain will skip on the cog.

1,800 miles is a surprisingly small number of miles to inflict that much damage to the chain and cogs, if it’s a small rider.

The Rohloff HG-Check is the tool you want to check cog wear.
― Lennard

Shimano Ultegra/SRAM compatibility

Dear Lennard,
I’m interested if, since SRAM hasn’t changed its shifters-derailleurs cable pull ratio since going from 10- to 11-speed, is there a slight chance of compatibility between Shimano Ultegra 6600 10-speed RD and any of SRAM’s 11-speed (right) shifter/brake calipers?

I know that it works, vice versa though, with Shimano mountain bike 10-speed SLX shifter and SRAM X9 RD, that I have on my bike.
— Tomislav, Croatia (Europe)

Dear Tomislav,
No, that will not work. Not even close.

The rear derailleur’s shift-activation ratio — the amount of lateral movement of the rear derailleur divided by the amount of cable pull to generate that amount of lateral movement (i.e., the number of millimeters of lateral displacement of the rear derailleur per millimeter of cable pull) — is built into the derailleur. And the cable pull — the amount the cable moves with each click — is built into the shifter. The cable-pull per shift multiplied by a derailleur’s shift-activation ratio is equal to the distance the derailleur’s chain cage moves laterally with each shift, and, to shift properly, this must be equal to the distance from the center of one rear cog to the center of the next (the cog pitch).

Cable pull x Derailleur shift-activation ratio = Cog pitch

Cog pitch is equal to the thickness of a cog (other than the largest or smallest cog) plus the thickness of the spacer separating it from the adjacent cog. Cog pitch decreases as the number of cogs increases. Shift-activation ratios, cable pull, and cog pitches vary not only with the number of rear cogs but also from brand to brand, and even sometimes from model to model within a brand.

A Shimano 10-speed road rear derailleur has a shift activation ratio of 1.7, and a SRAM 11-speed road shifter has a cable pull of 3.1mm, so:

3.1mm x 1.7 = 5.27mm cog pitch

That’s close to the 5.5mm cog pitch of a Shimano 7-speed cassette, but I don’t imagine that was the cassette you were hoping to use. That 5.27mm cog pitch is nowhere close to the 3.76-3.77mm cog pitch that the Big Three (Campagnolo, Shimano, and SRAM) all use on their 11-speed cassettes.

Are you using that ShimSram combo you mentioned on an 11-speed cassette? It should work, because the cable pull of that Shimano SLX 10-speed shifter is 3.4mm, and the shift activation ratio of the SRAM X9 rear derailleur is 1.1, so:

3.4mm x 1.1 = 3.74mm cog pitch

This is almost exactly the cog pitch of all three above brands of 11-speed cogsets. If not, the cog pitch of Shimano and SRAM 10-speed cassettes is 3.95mm, so you might be able to get away with that combo in a class-B shifting quality through maybe half of the cassette.
― Lennard

More on Carogna tubular tape

Dear Lennard,
Just watched your video on installing Carogna tubular tape. Amazing! This seems like a game-changer in many ways. One main question:

Assuming I can’t get all the glue off previously used tubular tires or wheels, would it be OK to use the tape anyway? Or do you suggest only using it on “virgin” tires/wheels?
— Jason

Dear Jason,
I don’t know the answer to your question, not having tried it, but I can guess and I can encourage you to experiment.

If you can get the rim clean and not the tire, the top surface of the Carogna tape is so sticky and thick that I think it would probably work fine. I’m confident it would stick to the old glue on the tire, and as long as the glue lumps were not super huge, I imagine it would fill in well enough.

As for not being able to get the rim clean, that might be more problematic, since the glue on that side is not thick enough to conform around the lumps.

You could try it and see what happens. If you already have the tire off, you would only lose the cost of the tape to give it a try and see if holds. Let me know if you do try it, please.
― Lennard

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Technical FAQ: Tape for tubulars, latex tubes, and more http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-tape-for-tubulars-latex-tubes-and-more_370761 http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-tape-for-tubulars-latex-tubes-and-more_370761#comments Tue, 19 May 2015 13:56:59 +0000 http://velonews.competitor.com/?p=370761

It’s hard to even get the tire started to come off the rim after it has been held on for awhile with Carogna tape. Photo: Lennard Zinn

This week, Lennard Zinn addresses questions about attaching tubulars with tape, a cracked bottom bracket shell, and more

The post Technical FAQ: Tape for tubulars, latex tubes, and more appeared first on VeloNews.com.

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It’s hard to even get the tire started to come off the rim after it has been held on for awhile with Carogna tape. Photo: Lennard Zinn

Attaching tubulars with tape

Dear Lennard,
I’m about to embark on a rite of passage as a roadie and begin using tubulars. I’m all for tradition, but I wouldn’t mind a less messy, less toxic, and less arduous approach to attaching tubular to rim. The reviews of the tubular tapes that have been on the market for a while are less than completely confidence-inspiring. But there’s a new product by Effetto Mariposa called Carogna tape. Would you consider putting it through the paces soon and telling us tech-mortals how you think it compares to a high-quality glue job in terms of performance and safety?
— Ken

Dear Ken,
The idea of a tape that could chop hours off of attaching tubular tires yet would adhere just as well as a superior gluing job would obviously be a game-changer for tubular users for the reasons you list.

I’ve been using various revisions of Effetto Mariposa Carogna gluing tape for a couple of years now, well before they were released to the market. I have been enthusiastic from the beginning, but the first two versions definitely were not ready for prime time; they did not adhere well enough for my tastes, and they were never sold to the public. This version now available for sale could be just the ticket for those wanting to save some gluing elbow grease, however. I have a number of wheels with the tires held on with Carogna, and those tires are really on there.

A difficult gluing environment is on carbon rims in cyclocross, and I’ve used this new Carogna tape with complete success for that on many wheels. Cyclocross tires, being larger in cross-section, do not mate in shape with the rim bed as well as road tires do. And, being taller, there is higher leverage on the tire when cornering than on a smaller tire. Furthermore, a tire holds onto the rim better the higher the air pressure it has in it, so with the lower pressures used in cyclocross vs. road (25psi vs. 125psi is a big difference), the pressure is not helping the bond much. Finally, the mud and foliage that cyclocross tires ride through, combined with pressure washing them clean, works hard on the edges of the glue job. Earlier versions of Effetto Mariposa tape were susceptible to getting dirt between the tape and the tire, but this current Carogna tape has so far been impressive at keeping dirt out and the tire on.

Carogna is different from most tubular gluing tapes in that its top surface is not only extremely sticky, but it is also very thick. The adhesive Effetto Mariposa used for it was developed for taping undersea communication cables together, so it’s meant for tough environments like wet, dirty roads and muddy ’cross trails. Its thick, sticky surface not only adheres to the tire with a strong grip, but it also flows over time to conform to the underside of the tire. This is important not only when the tire’s radius of curvature is larger than that of the rim, as is the case with a cyclocross tire, but also to conform around the raised ridge formed by the stitching.

You can see me trying to push this Challenge Chicane off of this ENVE XC rim. It had been on there with Carogna for many months, and I’d ridden it a lot in all kinds of slop. I eventually got it off of the rim, but it took a lot of work — similar to a good gluing job. Once the tire comes off the tape, you can then peel the tape off the rim. I find that the best way to do this is to roll it up as in the photo; if you just keep trying to tear it straight up, you can peel the two layers apart from each other and leave a thin layer of tape down on the rim.

Here is a video I did a while ago showing how to glue on a tire with Carogna tape.

Any of you out there who are using Carogna, please keep me apprised of your experience with it.
― Lennard

Latex tubes with carbon clinchers

Dear Lennard,
There seems to be a mix of opinions whether latex tubes are safe to use in carbon clinchers because latex tubes cannot handle heat as well as butyl tubes. Many manufacturers caution against latex tubes, but there are plenty of anecdotes of people running latex tubes without problems — you even seem to say latex tubes are not a problem.

What is the heat tolerance of the average lightweight butyl tube and latex tube? And, how often do carbon clinchers reach temperatures that would lead a latex tube to fail? Is there another reason besides the heat issue that makes latex tubes unsafe for carbon clinchers?
— David

Dear David,
I learned a lot from finding the answers to your questions. I have used latex tubes on carbon clincher wheels without problems, but I would not do it again, after getting the answer below from Challenge (which makes the world’s only seamless latex tubes); I would revise accordingly the answer I gave in the FAQ that you linked to.

Below are responses from the two big brands in latex tubes.

Interestingly, Challenge doesn’t mention this heat issue on its website, and the only mention I found on Vittoria’s site of separate latex tubes (as opposed to latex tubes sewed inside of tubulars) at all was this. Here is some more on the subject of care of latex tubes.

But to answer your last question, other than the heat issue, no, there is no other safety reason not to use them on carbon clinchers. In fact, since latex tubes have so much more puncture resistance (try taking a hammer to latex and butyl inner tubes lying on a table to see for yourself this rather profound difference), they are arguably safer on any kind of wheel where heat buildup isn’t an issue.
― Lennard

From Challenge:

It is correct to say that latex tubes should not be used in carbon clincher wheels. It is correct to say that latex does not handle heat well compared to butyl.

Butyl rubber can support much higher temperatures for longer periods of time.

The reason why latex works on carbon clincher wheels (this is my personal opinion), is due to the ability of the rider. Expert riders are able to do descents with limited use of brakes and [thus] give the possibility to the equipment to cool down. Never reach extreme heating. The heat is generated on the external part of the rim and will take time to transfer inside the rim. Generally between tire and rim strip, the tube has no direct contact to the carbon rim and if there is no rim strip it is on the cool part of the rim.

Heat in carbon [rims] does not dissipate fast and generally seems to be concentrated in the braking area.

Criterium and other types of riding do not have [the] problem of wheels heating, so latex can be used with no problem. As manufacturers, we do not know how consumers will use the product, and, to be on the safe side, we prefer to give warning not to use it.
— Alex Brauns
President, Challenge Tech

From Vittoria:

1. I have run latex with our 3T and Easton carbon clincher wheels with no issue at all, including significant descents in the mountains of Utah. I will, however, forward this to our product manager Christian Lademann for a detailed answer.
— John McKone
Vittoria Road Marketing

2. What is the heat tolerance of the average lightweight butyl tube and latex tube?
If the tube reaches the level of 100-140 degrees Celsius, all kinds of inner tubes will be destroyed.

And, how often do carbon clinchers reach temperatures that would lead a latex tube to fail?
This really depend on several factors, such as rim construction, -size, -resin and -tape. But mainly [it depends] on the end-user brake skills.

Agree that, “shorter, more powerful braking produces less heat buildup than does prolonged braking.” Similar to car brakes.

It’s not the tire bead, but the tube that cannot withstand the heat and give a sudden high pressure to tire bead. By the way, our tires run through a CQ that request 200 percent of the suggested maximum pressure. Example: Open CORSA CX 23mm 10.0 bar max tires have to withstand 20.0 bar at our derailing machine.

Is there another reason besides the heat issue that makes latex tubes unsafe for carbon clinchers?
Tubes are a rather sensitive product in general. Either Latex- or superlight Butyl tubes tend to explode suddenly, if not being used correctly. Some rules need to be followed:

1. Do not overheat the system
2. Do not lock the tube in between tire bead and rim hook
3. Prevent tube over-stretching in general — use recommended air pressure, rim tape and tube size
4. Prevent any sharp edges in the system
5. Prevent contamination with any oily substances

— Christian Lademann
Product Manager, Vittoria S.p.A.

Advice for road tubeless newbies

Dear Lennard,
I have been riding on road tubeless tires and wheels (Ultegra tubeless wheels Fusion 3 tires) for three years now and love them. Last year I rode over 3,000 miles without a flat. Most tubeless road bike riders would like to share this great experience with the clincher community but know there are big pitfalls for the tubeless newbie.

I did not always love my road tubeless tires. After my first puncture that would not seal, I hated my new tubeless tires and almost went back to clinchers. I felt abandoned, helpless, and ripped off. Most bike shops are of little help because most (but not all) of their service staff are unfamiliar with road tubeless and/or do not like the technology.

All road tubeless newbies will need to know how to mount and maintain their tubeless tires. They should also have to know how to fix a leak too large for the sealant but not large enough to trash the tire (these happen to me about once every 1,000 miles). These tasks become quick and easy with the right skills, tools, and tips, but are next to impossible when faced for the first time.

There needs to be a network of road tubeless riders that the tubeless newbie to contact when they need help, because they will all face these frustrating unsolvable (in the newbie’s eyes) problems. Fortunately, I watched the right YouTube videos, read the right blogs, and was able to figure out what needed to be done to make road tubeless riding a pleasure to ride. Not all newbies will be so lucky.

So to all road tubeless newbies … Please find a local road tubeless rider to help you through the learning curve (we are a lonely bunch and would enjoy the company). You will make a new friend and will soon love riding on your road tubeless tires.
— Arthur

Dear Arthur,
Thanks for the tutorial on road tubeless!
― Lennard

Regarding drilling holes in carbon frames

Dear Lennard,
I’d be careful about drilling holes in your bottom bracket. I’ve got a 2007 Trek Madone that has an aluminum shell insert at the bottom bracket. I bought the bike used in 2008 and after a few months I noticed creaking at the bottom bracket. After removing the cranks and bearings I could see the aluminum shell was cracked due to an extra hole drilled next to the cable guide fastener hole. The resulting stress concentration of the close holes, the holes not being de-burred, and the cyclical loading of the cranks caused a crack the connected to the main tube drain holes. Eventually the interface between the shell and carbon frame broke down. Calfee Design repaired the shell and frame, but what a waste. Most likely someone mis-drilled the cable guide and just drilled another hole. As an engineer in aerospace I understand most of the issues, but I’m still scared to drill holes without fully understanding the stresses.

Attached are a few pictures of the crack.
— Mike

The post Technical FAQ: Tape for tubulars, latex tubes, and more appeared first on VeloNews.com.

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Technical FAQ: Minimum tire pressure and more http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-minimum-tire-pressure-and-more_369794 http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-minimum-tire-pressure-and-more_369794#comments Tue, 12 May 2015 12:31:55 +0000 http://velonews.competitor.com/?p=369794

Photo: Caley Fretz | VeloNews.com

In this week's Technical FAQ, Lennard Zinn answers questions on tire pressure, battery mounting, and drilling holes in carbon frames

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Photo: Caley Fretz | VeloNews.com

On minimum tire pressure

Dear Lennard,
I read with interest your reply to Manny with regard to 25mm tyre pressures. I recently purchased 25mm Vittoria Open Corsa SC tyres, and these are clearly marked with “Clincher MIN to MAX pressure: 115 to 145 PSI.” This seems quite unreasonably high to me, so I’m wondering what is a safe minimum pressure to use with 25mm clinchers (would be interesting to hear from your contacts at other tyre manufacturers), and why does Vittoria see the need for such a high minimum pressure?
— Simon

Dear Simon (I sent this answer directly to Simon),
Here is the response to your question from Vittoria:

According to ETRTO, bicycle tires are allowed to deflect 30% of its height at maximum load only. We respect the ETRTO, but we do not limit the body weight of our customers. 115PSI minimum air pressure is the consequence for our high-end 25mm tire with its very flexible casing; the minimum air pressure is related to the worst case: heavy load, rear wheel, aged tire.

We will address this matter more precisely on our MY16 new models.
— Christian Lademann – Product Manager
Vittoria S.p.A.

I’m not going to tell you to do anything differently with your Vittoria tire than Vittoria’s product manager just told you. However, since you’re asking generally what minimum pressure you can with 25mm clinchers in general, I can answer it generally. The safe minimum tire pressure is certainly a function of rider weight, and you’ve not given me yours. I, at 174 pounds, have ridden safely for extended periods on many different 25mm clinchers, both standard clinchers and open tubular clinchers on smooth roads, at as low as 75 psi in the rear and 65 psi in the front. I haven’t measured to see if I get over 30% tire drop at those pressures, but tire squirm is not an issue for me at those pressures.
― Lennard

Dear Lennard,
Thanks for getting a half-sensible answer from Vittoria, although I do have to ask what they classify as a heavy load – do they consider worst-case to be a 300kg version of Sagan pulling wheelies? For the record I’m 80kg (176 pounds), so I don’t consider myself to be at the heavy end of the spectrum.

I decided to run my own test, as I’m sure wheel rim width is also a consideration. I’m using HED Jets, which have the 23mm wide C2 rims, and used butyl rubber inner tubes. The setup was a simple stationary test. I simply put my bike on its rear-wheel wheel stand, inflated the front tyre to the desired pressure, then stood in front of the bike with my hands on the handlebars and pushed down until I lifted myself off the ground. To capture the measurement I simply tied a steel ruler loosely to one of the spokes (not fixed to the spoke, rather just enough to keep the ruler upright during measurement), rotated the wheel so the ruler was perpendicular to the wheel contact patch with the floor, and setup my bike camera to capture the tyre deflection. I did the test on both Continental Gatorskins and Vittoria Open Corsa SC, these are the results rounded to the nearest millimeter:

Conti Gatorskins
No load tyre height (rim to floor): 26mm
60PSI : 6mm deflection, or 23%
70 PSI : 5mm, 20%
80 PSI : 5mm, 20%
90 PSI : 4mm, 15%
100 PSI : 4mm, 15%
110 PSI : 3mm, 12%
120 PSI : 3mm, 12%

Vittoria Open Corsa SC
No load tyre height (rim to floor): 26mm
60PSI : 7mm deflection, or 27%
70 PSI : 6mm, 23%
80 PSI : 5mm, 20%
90 PSI : 4mm, 15%
100 PSI : 3mm, 12%
110 PSI : 3mm, 12%
120 PSI : 3mm, 12%

While this is a static test and therefore doesn’t take into account Paris-Roubaix style cobbles, potholes, or road curbs, it is essentially bearing my full weight on one tyre. It seems you’d need to be running really low pressures to obtain 30% tyre deflection, and it also shows that regardless of the tyre construction being a “supple” cotton casing or a “bullet proof” rubber/Kevlar construction the deflection is similar until you get to really low pressures.
— Simon

Dear Simon,
Cool experiment! Thanks for doing that and giving us the results!
― Lennard

Mounting a Campagnolo battery

Dear Lennard,
I am lucky enough to have a Record EPS group being installed on a Cervelo S3, size 48. The shop doing the build said that the internal Campy battery I have will not mount internally in the down tube because the bolts provided are not long enough. They also said the seat post and seat tube are too small to house the battery. They are mounting the battery with the Campy external mounting kit, but I was wondering if there is a way to get longer mounting bolts. I cannot seem to find anything about this online or in the Campy catalogue. The bolts, as it was explained to me, are pretty unique. If there is another solution to getting the battery to rest safely inside, I’d be very grateful.
— Ryan

Dear Ryan,
I don’t think it requires all that much imagination to come up with a solution to use the internal EPS battery in the down tube of your bike, if the supplied bolts are indeed too short. For those wondering, the internal Campy EPS (V2) battery screws in behind the bottle bosses inside (ideally) the seat tube, or inside the down tube in the case of an aero seat tube too narrow for the battery to fit. If memory serves, the kit comes with three bolts, all of different length, and you only use two; I wonder if one of them is long enough …

Yes, the EPS V2 internal-battery-mounting bolts are unique, having M4 thread that will pass through the M5 threaded bottle boss bole and into the battery, then a hex head, and then M5 thread above that for a nut to hold the bottle cage on. But with some M4 (4mm X 0.7) all-thread, you could certainly secure that battery in your down tube.

You could use pieces of the all-thread long enough to thread into the battery holes, then drop a washer followed by a nut onto each, and snug the nut up against the face of the bottle boss. Then you could drop the bottle cage onto the extensions of the all-thread sticking up from the nuts, and put another washer and nut on each to tighten the cage on. Then you’d cut off the excess length of the threaded rods so they wouldn’t tear up your bottle.

You still need the special Campagnolo installation tools to mount the EPS V2 battery in the down tube. Those consist of a pair of cables with a threaded end to screw into the end of the battery and suspend it inside the down tube while you secure the battery by tightening it in place with bolts through the bottle bosses. Thread the tools in loosely enough that you can unscrew them by twisting the cables counterclockwise after the battery is secured in place.
― Lennard

Staying hydrated

Dear Lennard,
Your reader, Jeff, appears to be looking for a solution so he does not have to carry water on his back. There is a wonderful product available that solves this problem: showerspass.com/veleau
— Matt

Regarding drilling holes in carbon frames

Dear Lennard,
In this week’s FAQ the question of owners drilling holes in carbon frames was discussed (in this case it was holes in the down tube), and it was considered to be a bad idea. However, in the past I have seen you advocate drilling bottom bracket drain holes in bikes that didn’t have them. Is this still true? Or shouldn’t you drill drain holes in carbon BB’s either? The center of the BB seems to be a relatively low stress area that also has a large wall thickness so I wouldn’t think it would be a problem. What is your take?
— David

Dear David,
While I was thinking about metal frames when I wrote that, I’m confident that drilling a small drain hole in the underside of a bottom bracket shell would not lead to failure there. That’s a thick area that sees minimal stress.

On the other hand, a carbon frame can’t rust, so the necessity for drainage is not the same as in steel, aluminum, or magnesium frames.
― Lennard

Dear Lennard,
Though I agree drilling big holes in frames is a huge risk, and understand comments from manufacturers, there are situations where this could be OK.

Last spring I built up a Pinarello FCX with Shimano hydraulic disc Di2. To route wiring internally I had to drill two small holes for the front and rear dérailleur e-tube wires. I was careful to choose locations that would be loaded in compression rather than tension – understanding that areas with carbon in tension would likely lead to failure. I realize I voided the warranty, but a year later I’ve had zero issues.

I also work part time at a shop and have done the same thing on two other bikes with no issues.

Not a job for the faint of heart or with an unsteady hand, but not something that creates big concerns IMHO.
— Paul

Dear Paul,
I got a number of letters from people trying to figure out how they could safely drill holes in their carbon frames. I just can’t get behind any of them, unless you have the okay of the manufacturer. While your method is safer than not taking tube stress into account, it requires an understanding of frame loading. And, you have no idea of the internal construction of the frame; the manufacturer may have already minimized material in that area due to its relatively low stress.
― Lennard

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Technical FAQ: Drilling holes in carbon frames and more http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-drilling-holes-in-carbon-frames-and-more_369031 http://velonews.competitor.com/2015/05/bikes-and-tech/technical-faq/technical-faq-drilling-holes-in-carbon-frames-and-more_369031#comments Tue, 05 May 2015 13:52:46 +0000 http://velonews.competitor.com/?p=369031

The only holes in a frame should be the ones drilled by the manufacturer. Photo: Logan VonBokel | VeloNews.com

In this week's Technical FAQ, one reader asks Lennard Zinn if it's safe to drill holes in the carbon frame of his bike

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The only holes in a frame should be the ones drilled by the manufacturer. Photo: Logan VonBokel | VeloNews.com

Drilling holes in a carbon frame

Dear Lennard,
Can I drill holes in the down tube of my carbon mountain bike frame without negatively impacting its structural integrity?

The back story: Rather than using a backpack for my hydration bladder, I place it in a frame bag, which eliminates the weight on my back and is much more comfortable. On a recent ride, I realized that the fairly massive down tube on my bike (a carbon Silverback 29er), offers significant capacity; utilizing it would mitigate the need for even a frame bag. My idea is to drill a 3/8″ inch hole on the upper side of the down tube near the head tube, and another 3/8″ hole on the bottom of the down tube near the BB. I would then sanitize the inside of the tube with food-grade chemicals, plug the bottom hole with a threaded rubber stopper, fill the down tube with water, and insert the appropriate length of 3/8″ OD surgical tubing into the upper hole, affixing the bit valve end on the bars.

Again, I am wondering if drilling holes of this nature would significantly reduce the structural integrity of the frame. (By the way, I hereby indemnify you from any and all ramifications of me drilling holes in my frame.) This may seem like a dumb question (“Of course it’ll screw up the frame!”) but, for example, the fifth picture in the VeloNews photo essay on the new Trek carbon IsoSpeed frame clearly shows a hole for a “rivet or a port” on the bottom side of the down tube. To make a long line of reasoning short, if Trek can do it, why can’t I?
— Jeff

Dear Jeff,
That’s a very poor idea. It’s not a good idea to drill a hole, particularly that big of a hole, even in a metal frame. But at least on a metal frame, you’re not cutting through fibers as you are on a carbon frame.

Below are some responses you should pay attention to.
― Lennard

From Specialized:
Drilling holes in a down tube is a bad idea. The holes will create stress concentrations where cracks could form, compromising the structural integrity of his frame. If we meant for holes to be drilled in those locations we would have reinforced the tube walls in those area. (Needless to say this would void the bike’s warranty). Most of the holes in our frames are drilled, but we have specific reinforcements in those areas to prevent structural issues and the drilling process is very controlled and repeatable.
— Luc Callahan
Engineering Manager- Road
Specialized Bicycle Components

From Trek:
There is no circumstance where a hole can/should be drilled in a carbon frame by anyone other than the manufacturer. The reason we can drill holes in frames is that we specifically design areas with reinforcement for post-molding machining processes. We make intricate and exact fixtures that can take advantage of those areas with the appropriate cutting tools. There is absolutely no circumstance where we would feel comfortable with anyone outside of Trek drilling a hole in a carbon frame.
— Ben Coates
Trek Road Product Manager

More on Trek’s skewer recall

Dear Lennard,
I don’t know if I should be sending this email to you or to “Legally Speaking,” but here we go.

I bet Mr. Tullio Campagnolo is turning in his grave. Between the lawyer lips and this recall, he must be saying, “it’s a simple device, people, but you keep finding ways to screw it up.”

So the video shows the mechanic putting the lever on the side with the disk brake. Is there a law against putting it on the non-brake side?

He describes a scenario were the lever “just opens up.” I’m guessing that this happens because the skewer is not tight enough and/or pointing forwards. So Trek’s “solution” is to replace it with a shorter lever. Sure, it prevents the lever from catching in the disk, but it does not solve the actual problem of not enough tension. In fact a shorter lever will make it harder to tighten.

So here is my question for Professor Zinn: Are there any skewers on the market that let the rider know that skewer is tight enough? Anything that ensures proper alignment, i.e., not pointing forward?

I do realize that the actual solution is to teach new riders the proper way. Each year on a charity ride that I do, I point this out to at least one rider. One guy even said, “That’s how the shop told me to do it.”
— John

Dear John,
I know of no skewers that tell you when they are tight enough, or that they are oriented in an approved direction …

I have always put my lever on any disc-brake front wheel on the non-brake side, but I am amazed at the scorn I occasionally get from people who find it unsightly to have the skewer lever on the drive side.

I believe that having the lever on the non-drive side is absolutely the way to go to prevent getting greasy fingers on the disc and to prevent inadvertently bending the disc by pulling on it with the fingers when pushing the lever over with the heel of the hand. That said, since you can’t prevent people from turning it around the other way. Trek simply training its shops to put the skewer lever on the drive side is probably insufficient to address this issue, which for three people was very serious.

Unlike the front, you can’t reverse the skewer on the rear so the lever is on the drive side, since the lever would be in the way of the derailleur. While a locked-up rear disc would not be as catastrophic as one on the front, it is still not something you’d want to have happen. Trek pretty much had to address this issue in the way that it has.

The recall replaces the skewers with ones that don’t flip open past 180 degrees.

It seems unlikely that other manufacturers of disc-brake bikes aren’t also selling skewers that flip open past 180 degrees; I wonder how many other bicycle brands will follow Trek’s lead.
― Lennard

More on disc-brake hubs on bikes

Dear Lennard,
You stated, “You aren’t apt to find disc-brake hubs with fewer than 32 holes to attach them to.”

Small detail, but I’d like to point out that DT Swiss offers road disc hubs in hole counts of 20, 24, 28, and 32, in Classic flange, plus 24 and 28 in Straight Pull flange hubs. Of course, a low spoke count disc wheel is not for every rider, but we do make the options available to wheelbuilders.
— Steven Sperling
Tech Manager
DT Swiss, Inc.

Dear Lennard,
In a recent column, “Technical FAQ: Disc brakes in road racing,” Mark commented that since kinetic energy is proportional to the square of speed, braking power (and therefore heat generation) was proportional to the square of speed. This isn’t strictly true. If you are braking to come to a stop, you lose all of your kinetic energy, which is proportional to the square of the initial speed, as Mark states. However, when braking on a descent, you aren’t typically losing kinetic energy, but rather preventing gravitational potential energy from increasing it. The rate of loss of potential energy is proportional to road grade times speed, so if you brake to maintain speed on a long descent, the rate of heat generation will be approximately proportional to the speed, not the square of speed. So descending a 20 percent grade at 30 kph would result in twice the rate of heat generation as descending a 20 percent grade at 15 kph. Total heat generation depends only on the potential energy lost, so speed doesn’t matter for total heat, which determines maximum temperature increase on very short descents. Although, if the heat sink (in this case the rotor) is losing heat to the air, then the peak temperature will be roughly proportional to the rate of heat generation on long descents where “steady state” is reached. This all of course ignores power dissipated to wind resistance, rolling resistance, etc. But the key point is significant kinetic energy is not being lost when speed is approximately constant, and there’s no reason to expect heating proportional to the square of speed.
— Dan

Dear Lennard,
Just read your Tech FAQ on disc brakes. Although I agree that it probably doesn’t make sense to convert rim brake rims to disc, folks are not limited to 32-hole hubs. I’ve run two disc brake bikes for over three years now. I live in Seattle and get most of my training in via long commute rides year-round. Prior to going to disc brakes, I went through a rim a winter despite careful and regular cleaning of the brake track. I wanted a go-fast, year-round bike. TiCycles built me a custom road race geometry frame with disc brakes (not a converted gravel or cyclocross). This bike was originally built with Ultegra 10-speed Di2 and Avid BB7s. I upgraded it to Dura-Ace 11-speed and Shimano hydro about a year ago (as an aside, no problems with brake fade even on 95+ degree days on long mountain pass descents). I also have one of their gravel disc frames that got the Ultegra Di2 and BB7s as hand-me-downs.

At any rate, I have four sets of wheels, all disc brake. On my road bike, I run 28 hole, three-cross for both wheelsets. For dry weather, a set of 28-hole DT Swiss 240 centerlock hubs laced with DT Aerolite spokes to Reynolds Competition 46 rims (DT Swiss bearing only make it one winter season for me, so I consider them junk for wet weather riding). For wet weather, I run 28-hole Chris King R45 disc hubs laced with Sapim CX-Ray spokes to Hed Belgium+ disc rims. I weigh about 163 pounds and ride with a messenger bag for about 75 percent of my miles. Both of these wheelsets have seen a lot of beating and are holding up very well. On my gravel bike, I do run 32-hole hubs (both Chris King ISO discs with Sapim CX-Ray spokes to Belgium+ disc rims for my fast tires and Sapim Force spokes to Stan’s Grail rims for my mud tires).
— Joel

The post Technical FAQ: Drilling holes in carbon frames and more appeared first on VeloNews.com.

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Technical FAQ: Chainring and cog compatibility http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-chainring-and-cog-compatibility_368165 http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-chainring-and-cog-compatibility_368165#comments Tue, 28 Apr 2015 18:42:39 +0000 http://velonews.competitor.com/?p=368165

Photo: Logan VonBokel | VeloNews.com

Lennard Zinn helps readers sort out a variety of component combinations that mix and match shifters, derailleurs, different brands, and more

The post Technical FAQ: Chainring and cog compatibility appeared first on VeloNews.com.

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Photo: Logan VonBokel | VeloNews.com

Dear Lennard,
Do you know if there are any 52/36T chainrings with a 130 BCD? Am trying to go mid-compact without having to buy a new powermeter (I have a Quarq crankset).
― Chris

Dear Chris,
A little geometry lesson is clearly in order. No, there is no such thing as a 36-tooth chainring for a 130mm bolt-circle-diameter (BCD) crank. That’s because 130 BCD means that the centers of the chainring bolts are 65mm from the center of the crank spindle. But the smallest chainring, with tooth valleys external to chainring bolt holes drilled on a 130mm bolt circle, has 38 teeth. A 36-tooth would not work, because the bolts would be among the chainring teeth! (The valley-to-valley diameter of a 36T chainring is 137mm, but the heads of the crank bolts are 11mm across, so the outer edges of the crank bolts on a 130mm bolt circle scribe a circle 141mm in diameter, thus overlapping where the chain needs to go by 2mm.)
― Lennard

Dear Lennard,
I want to buy a rear wheel for my trainer so I don’t have to change out my trainer tire with my road tires. I am running a 10-speed system but have old 9-speed cogs. Can I use those with my 10-speed system?
― Robert

Dear Robert,
Not if you want it to shift properly, you can’t. Perhaps on your trainer you only use one or two gears, in which case you could adjust your derailleur to run quietly on those, or instead, only use those gears that it already runs quietly on. This may be good enough for your indoor-training purposes. But since the cog pitch (the center-center distance between cogs) is greater on a 9-speed cassette than on a 10-speed cassette, your 10-speed system will only work on a limited number of the rear cogs on a 9-speed cassette.
― Lennard

Dear Lennard,
I have ridden Campagnolo 11-speed for a number of years and have Athena groupsets on two of my bikes.

I am looking to upgrade another bike to 11-speed — I wanted to know if there is a chance that a ‘mix and match’ approach would work.

My idea would be to use Athena Ergopowers (I prefer the ergonomics) with a set of Shimano derailleurs (cheaper than the Campagnolo version) to create a cost-effective 11-speed bike.

I plan to use wheels with Campagnolo cassettes (that I already have) and a Campagnolo (compatible) chain.

Will the gears shift correctly, and are there any other issues that I would need to be aware of in terms of the brakes?
― Finbar

Dear Finbar,
No, the gears will not shift correctly unless you take some additional measures. That said, this setup will work better without modification than mixing Campy 10-speed or 9-speed levers with Shimano 10-speed or 9-speed derailleurs. As for the brakes, if you’re going to use current Shimano brake calipers with Campy levers, those will not work well, either.

Campagnolo 11-speed (and 10-speed, and late-model 9-speed) rear derailleurs have a shift-activation ratio of 1.5, meaning that for every millimeter of cable pull, the derailleur moves laterally 1.5mm. Shimano 11-speed road rear derailleurs, on the other hand, have a shift-activation ratio of 1.4, meaning that for every millimeter of cable pull, the derailleur moves laterally 1.4mm. The cable-pull per shift of a Shimano 11-speed road STI lever is 2.7mm, while the cable-pull per shift of a Campagnolo 11-speed Ergopower lever is nominally 2.6mm, although many Campgnolo levers in the past have also had a variation in cable pull over the range of the gears as well, and I suspect the actual average cable pull for an 11-speed Campy lever is closer to 2.5mm.

Cog pitch (i.e., the center-to-center spacing between cogs, which is also equal to the thickness of one cog in the center of the cassette and its adjacent spacer) of all 11-speed cassettes, whether Shimano, Campagnolo or SRAM, is between 3.76-3.79mm by my measurement. You’ll notice that this is also equal to Shimano’s 11-speed road cable pull times its shift-activation ratio (1.4 x 2.7mm = 3.78mm). So, substitute in a Campy lever, and you get 1.4 x 2.5mm = 3.5mm, which is a smaller jump than the actual spacing between cogs (and even if you use 2.6mm for the Campy cable pull, which I think is inaccurate, you come out with 3.64, which still is narrower than the actual cog pitch). This is why J-Tek made cam-type, cable-pull-adaptor units that increased or decreased the amount of cable pull per shift so that a user could make a “Shimagnolo” mashup work.

In short, the difference in shift-activation ratios between the Campy and Shimano 11-speed rear derailleurs is small enough that shifting will be okay on some of the cogs but not on all of them.

You didn’t say you were changing brakes, but you asked about them. Shimano road brake calipers built for Shimano levers that send the shift cables underneath the handlebar tape require more cable pull than previous Shimano calipers. And those previous Shimano calipers, which work with STI levers where the shift cable sticks out of the side of the lever body, also use the same cable pull as current and past SRAM and Campagnolo calipers. So if you use current Shimano road brake calipers with Campagnolo levers, you will have more leverage and hence more braking power than designed, and you will have too little cable pull to bring the pads to the rim as quickly as designed.
― Lennard

Dear Lennard,
In a past column of yours, you note that 9- and 10-speed cassettes can be used on 11-speed cassette bodies without any problem.

I’ve been looking at new wheels and sometimes the wheels are advertised as “10/11″ speed Campagnolo compatible. I contacted one seller and he insisted that the wheels were only compatible with 10/11-speed Campagnolo cassettes.

So, are there cassette bodies which are only Campy 10/11-speed compatible or should a so-called “10/11″ speed cassette body be compatible with 9-, 10-, and 11-speed cassettes?
― Collin

Dear Collin,
There is no such thing as a Campagnolo freehub body that is compatible with Campy 10-speed and 11-speed cassettes and not with a Campy 9-speed cassette. The current Campagnolo freehub spline design came in with the advent of Campagnolo 9-speed drivetrains. A Campy freehub body that is compatible with a Campy 10-speed or 11-speed cassette is also compatible with a Campy 9-speed cassette.
― Lennard

Dear Lennard,
In attempting to convert several bikes from Campy 10 to 11, and hoping to use my existing wheels/hubs (if possible), I’ve run into problems finding replacement freehub bodies (i.e., 10-speed to 11) to make my desired hub conversions. I should add that several of these wheels have Shimano or SRAM hubs/cassettes, but they’ve worked reasonably well with spacer swaps, rear derailleur tweaks, and other “tricks” employed to allow Campy 10 shifters to be used with Shimano/SRAM 10-speed cassettes. Unfortunately, I’m about ready to give up on the freehub-swap idea for these wheels, which would have been the simplest, path-of-least-resistance option to letting me run new Campy 11 shifters with any brand’s 11-speed cassettes.

My next option, while still somewhat simple but a good bit more costly, would be to run the new Shimano XTR 11-speed cassette, which I know fits on Shimano/SRAM 10-speed hubs. I don’t mind having the extended range, since most of these wheels are for ‘cross/gravel/dirt and tandem applications. But, my primary question is: is it safe to assume that the XTR 11-speed cog spacing is the same as that on everyone else’s 11-speed cassettes? In other words, will my Campy 11-speed shifters play nicely with the XTR cassette (given that I make the necessary adjustments to the rear derailleur to accommodate the enlarged cassette)? Here’s hoping that’s the case, and I won’t need to purchase a bunch of new rear wheels. Or — if you know of any other solutions to this dilemma, please let me/us know …
― John

Dear John,
Yes, the cog pitch on XTR 11-speed cassettes is the same as on road 11-speed cassettes, whether Shimano, Campagnolo or SRAM, which is between 3.76mm and 3.79mm by my measurement.
― Lennard

The post Technical FAQ: Chainring and cog compatibility appeared first on VeloNews.com.

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Technical FAQ: Disc brakes in road racing http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-disc-brakes-in-road-racing_367422 http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-disc-brakes-in-road-racing_367422#comments Tue, 21 Apr 2015 14:17:17 +0000 http://velonews.competitor.com/?p=367422

The UCI will begin to allow disc brakes in the WorldTour this summer. Photo: Logan VonBokel | VeloNews.com

This week, Lennard Zinn addresses the UCI's announcement that it will allow disc brakes to be used in the pro peloton this summer

The post Technical FAQ: Disc brakes in road racing appeared first on VeloNews.com.

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The UCI will begin to allow disc brakes in the WorldTour this summer. Photo: Logan VonBokel | VeloNews.com

Converting existing wheels for discs?

Dear Lennard,
With the UCI announcing its strategy for road discs, I guess it’s now no longer a matter of “if” but “when.” For those of us with some nice carbon wheels we’d like to keep riding on that new super-disc frame, what’s your opinion on rebuilding (with the appropriate cross-lacing of course) the rims with disc hubs? OK, some math required on whether selling the wheelset and replacing is more economical, but the range of disc wheels isn’t that great right now. For example, would there be issues with different loads on the spoke holes? I’d accept that any warranty would be long gone.
— Phillip

Dear Phillip,
I think that is a poor idea, because the spoke drilling in the rims was not done with disc brakes in mind. That the warranty would be void would be the least of your problems.

First off, the spoke count would probably be too low for all but super-light riders to safely use disc brakes with those rims. And you aren’t apt to find disc-brake hubs with fewer than 32 holes to attach them to.

Secondly, many radially-spoked front carbon wheels have a spoke count that is not a multiple of four. This is also a non-starter; if your wheel has 18 or 22 spokes, you can’t lace it with a crossing spoke pattern.

Thirdly, unless you have crossed spokes on both sides of both the front and rear wheels, the angles at which some or all of the spoke holes in the rims were drilled will be wrong. On radially-spoked wheels, the holes will have been drilled radially — oriented directly from the rim toward the center of the hoop. The carbon at the V of a deep-section carbon rim is quite thick, so if you come out of such a hole with a spoke nipple directed radially inward and then try and lace it to a spoke coming at a crossing angle, it will not line up. It will bend the spoke and tear the carbon at the spoke hole when you tension the spoke. And if you have a radial wheel with just a carbon “skin” forming the deep-section part of it, the hole in the rim bed for the nipple lines up with the hole in the skin and the center of the hub flange, so trying to make the spoke curve at the edge of the skin to a hole in the hub flange for a crossing pattern will just distort and tear the skin as soon as tension is applied to the spoke.

Sorry to be the bearer of bad tidings, but you have to start with rims drilled for a crossing pattern, and they will probably have to be 32-hole.
― Lennard

Reader comments about disc brakes in road racing

Dear Lennard,
The letter from Ante, which appeared in the April 15 Tech FAQ, illustrates two common misconceptions about disc brakes on road bikes. Firstly, Ante’s letter contends that smaller rotors can be on road bikes because road tires have less traction than MTB tires. This is generally not the case — road tires on smooth pavement can usually provide more traction than knobby tires on dirt. Road tire traction is high enough that in practice, the braking limit on a road bike is often not the traction limit, but the tip-over point — the point when the forward weight shift from braking causes the rear wheel to lift off the ground and the bike begins to do an endo. (You can test this yourself by riding at a slow speed on smooth pavement and clamping the front brake trying to induce a front wheel skid — if you brake hard enough, you’ll find that the rear wheel lifts off the ground before the front wheel can begin to skid). In other words, road tires often have more traction than can actually be used for braking.

The second misconception is that the size of the rotor is selected primarily based on required braking force. In fact, the largest factor for selecting rotor size is more likely to be the ability to dissipate energy. Brakes work by converting a bike’s energy of motion (kinetic energy) into heat. Since kinetic energy increases with the square of speed, every doubling of speed will increase kinetic energy four-fold. Since road bikes typically go faster than mountain bikes, they will have far more kinetic energy that needs to be dissipated when stopping. Combine that with the very long road descents often found in the mountains, and there can be a very large amount of energy transferred to the brakes. Larger rotors may be required to absorb and dissipate this larger heat energy.

If, as contended in the letter, disc brakes are to be weakened as a safety factor to prevent riders from going over the bars, this might be accomplished by reducing the overall system leverage rather than reducing rotor size. This would have the additional advantage of increasing pad clearance, improving wheel interchangeability, and speeding up wheel exchanges.
— Mark

Dear Lennard,
I come again to the same conclusion as I did back in last November and even last summer when road disc brakes have been discussed. “Road Disc Brakes??? We don’t need no stinkin’ road disc brakes!”

Seriously, there is no problem that they adequately address. Road discs are poor options in many ways. And they cause a lot of problems that didn’t exist before. I really wish the product managers would stop trying to force them on the market. If someone must run a lighter weight carbon rim, they better find a rim that has an aluminum braking surface (a la Mavic), or bone up for tubulars. Otherwise, just get a nice set of aluminum clinchers. In many ways, they are tough to beat. It’s hard to find new and additional problems with either of those two approaches. Let’s get behind this and bury those road discs in a giant hole in the desert! (This time with no ranger in a power wagon to get their way out.)
— Kurt

Dear Lennard,
One of the touted cons about disc brakes in road racing is that wheel changes would be complicated and slow. The racing motorcycle crews have solved this by having the complete chain and sprocket assembly retained on the frame/fork by a dedicated bearing carrier (see video). On some motorcycle versions, the brake caliper and rotor also stay secured in the frame/fork. This way a wheel is just a hub and rim with an engineered interface to slot into the brake/drive systems, which are retained in the frame. The motorcycle example is obviously heavy but some elegant design could make a bicycle version almost the same weight as the current standard disc wheel designs and invisible when assembled.

If properly designed and implemented across the peloton, this could enable faster wheel changes than currently experienced with rim brakes (certainly for the rear). Also, brake and drive system alignments would be irrelevant.
— Mike

Dear Lennard,
I’ve been following this discussion about overheated disc brakes, and I just have to say that the day these things show up on the start line of amateur crits is the day I quit racing. We already take stupid risks when we do our little local races; why in the world should we add one so potentially devastating? So that disc brake makers can make their millions (or whatever they make, I have nothing against them, per se)?

Please, USA Cycling and UCI, keep these things out of road racing! They’re not needed!
— Thom

Dear Lennard,
I believe the debate over disc brakes on road bikes and the comments regarding their safety is ridiculous and overblown.

Disc rotors are not really that much of a safety concern in regards to getting sliced or burned. For one, a spoked wheel is way more dangerous than a disc rotor. For two, the buildup of heat, especially in the pro peloton, is another non-issue. If a rider is dragging his brakes, enough to heat them to a scorching degree, he is doing something wrong and should re-evaluate his skills.

I could see some heat problems on a casual rider, who may drag their brakes, though, but better braking is a good thing.

The only issue I see is the thru-axle or standard QR dropouts being used; I know the thru-axle is a better way to go, but it would slow wheel changes.
— Jeff

Dear Lennard,
If riders are so scared of those sharp brake discs, maybe they should stop using chainrings. Lets all switch to belt drive and hub gears. Maybe we should stop racing on the road and its nasty harsh surface and start racing inside velodromes lined with cotton wool.

Are these people serious? It’s the fear of the unknown.
— Ray

Dear Lennard,
Anyone who’s gone down a long descent with discs knows just how hot a disc can get. But truly, how common are mass pileups in pro races at the bottom of long descents? It seems like most crashes on long descents take out a couple of riders as they are single file and more often than not occur in the rain, when the disc would be cooler anyway.

Most mass pileups seemingly occur when the group is bunched up riding almost tempo or when they are going flat out. I would assume the discs leading up to the initiation of the pileup are at a fairly cool/ambient temperature. So it seems to me that at worst, the rider is going from say 35 mph to 10 mph (not 0 mph because then they would’ve stopped and not crashed!) in a matter of less than a couple seconds. Assume too that the rider is not skidding the tire. How fast can a disc heat up in less than 2 seconds? If the rider is skidding the tire, then even less heat is getting into the disc.

The edges of discs are indeed sharp. But the femoral artery isn’t exactly near the surface. There is not a lot of space between the disc and the wheel/frame/fork to actually get the disc into the artery. I’m not saying it is impossible, it just isn’t likely. I don’t see discs being any more dangerous than a cassette or chainrings in that regard. Those types of injuries do occur — I crashed in a mountain bike race earlier this year and sliced a vein in my ankle with the chainring and I’ve seen a couple of people get stitches in their faces from chainrings from mass pileups on the road over the last 25 years or so. Do you think a disc is intrinsically more dangerous than a cassette or chainring in that regard?
— Craig

The post Technical FAQ: Disc brakes in road racing appeared first on VeloNews.com.

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Technical FAQ: A drivetrain hack, tire pressure, and road discs http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-a-drivetrain-hack-tire-pressure-and-road-discs_366646 http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-a-drivetrain-hack-tire-pressure-and-road-discs_366646#comments Wed, 15 Apr 2015 14:09:16 +0000 http://velonews.competitor.com/?p=366646

And with the longer rear derailleur cage, it can handle extreme cross-chained combinations, like a 50-40t, shown here.

A reader explains how to accommodate wide gear ranges on a road bike, Lennard talks tire pressure, disc brakes, and more

The post Technical FAQ: A drivetrain hack, tire pressure, and road discs appeared first on VeloNews.com.

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And with the longer rear derailleur cage, it can handle extreme cross-chained combinations, like a 50-40t, shown here.

Dear Lennard,
Seems like there’s a lot of interest in 10- vs. 11-speed as well as road vs. mountain group compatibility. I just completed a mix/match combination I think your readers would like to hear about. I have a Giant AnyRoad CoMax with Shimano 105 11-speed group. The bike has a compact 50-34 crank and 11-32 cassette with 32mm tires from the factory. After taking a group trail ride with mixed cross and mountain bikes, I soon discovered the climbing/traction limitations of the factory tires/gearing in a mountain bike environment. I wanted to be able to swap between wheelsets with 32mm cross tires to as big a tire as I could fit in the frame with even lower gearing. The 11-32 cassette is the lowest geared road 11-speed cassette available, and I didn’t want to change to a mountain bike crankset. The solution, it seemed, was to use the XTR 11-40 11-speed cassette. I purchased a used Giant mountain bike 10-speed wheelset and mounted a Panaracer Firecross 45mm tire on the front and a Bruce Gordon Rock-n-Road 43mm tire on the rear.

Since the XTR 11-speed cassette has the same hub width as a 10-speed cassette, it mounted to this new wheelset without modification. With a 50t chain ring and 40t cog, the stock 105 medium-cage rear derailleur wasn’t up to the task of taking up that much chain, and the long-cage mountain-bike derailleurs have a different pull ratio and are therefore incompatible. Also, there isn’t a “B” screw long enough to keep the upper jockey wheel from rubbing that 40t cog.

What I needed was a long-cage 11-speed road derailleur. After examining the exploded views of the Shimano road and mountain-bike rear derailleurs I found, it appeared, the long cage from a direct mount Deore LX 10-speed RD-T670-SGS mountain-bike derailleur would interchange with the 105 medium-cage. I purchased a used Deore RD-T670-SGS, removed the cage/P-tension spring, removed the 105 cage/P-tension spring, and, sure enough, the mounting/pivot pins are identical. I installed the Deore long cage/P-tension spring on the 105 and now have a long cage 105 11-speed rear derailleur.

Prior to my rear derailleur “hack” I would switch chains when I would switch between wheelsets. Also, I reversed the “B” screw, had it adjusted all the way out, and had to install a spacer between the screw and derailleur hanger to prevent jockey wheel rub.

The Long Cage 105 derailleur “hack” solved two problems:
1.) I no longer have to switch chains when switching wheelsets; the long cage easily handles the longer chain.
2.) The upper jockey wheel on the Deore cage is offset slightly away from the cassette compared to the 105 cage. This allows an almost normal “B” screw adjustment even with that big 40t cog.

The time it takes to swap cages/P-tension springs is about 30 seconds (not including chain) and for me was under $30. I haven’t priced just the cage from Shimano but these Deore derailleurs can be found used for cheap. I can cross chain 50-40 or 34-11 with no issues and it shifts flawlessly. Best of all, since it’s factory Shimano parts, it doesn’t look like a hack; it looks factory.
— Tom

Dear Tom,
That’s great! Thanks for sharing with us your elegant solution to getting a wider gear range on a bike with road shifters.
― Lennard

Dear Lennard,
I live in a year-round warm, humid climate (Florida). As a practice, I pull the seatpost periodically to drain any accumulated water out of my (carbon) frame. Generally no water comes out, but the inside of the frame has a really musty odor of mold/mildew. What suggestions do you have to de-funk/sanitize the inside of a frame?
— Carl

Dear Carl,
Wow. That’s a new one on me. I’ll bet bleach would do the trick. Maybe put it in a spray bottle (you could even dilute it some with water) so you can spray down all sides of the seat tube without tearing your bike apart. Spraying rubbing alcohol inside could also be worth a try and would evaporate faster but might not sit long enough on the mold to kill it the way Clorox would.

Once you’ve removed the bottom bracket, you can also pour bleach inside the frame and slosh it around inside all of the tubes.
― Lennard

Dear Lennard,
I just read your response to the gentleman with the “slice tire” problem. A tire pressure chart from Bicycling Quarterly you’ve posted in the past recommended extremely high pressure (130psi) for me in the back and milder on the front (90psi). According to the Vittoria tire pressure guide, I should be running 130 in the front and 135 in the rear (I weigh 225 running Vittoria Corsa 25’s on wide Bontrager RXL TLR rims) I did have several “explosive slices” and even blew a couple of sidewalls using that combination. Since then, I’ve switched to Pave 25’s and lowered my pressure to 110/115 (f/r) and haven’t had any problems. I’ve experimented running lower, but that seems to be the sweet spot, as far a still rolling quickly. However you said you never run above 75 or so … In your opinion am I still running too much pressure?
— Brian

Dear Brian,
What you are doing sounds reasonable with your weight. I weigh over 50 pounds less than you, and that’s what I can get away with.

I should note that the Bicycle Quarterly tire pressure chart you reference did not take wide rims into account.
― Lennard

Dear Lennard,
I recently had the misfortune, due to inattention, to hit a traffic island with my 2013 Specialized Pro Tarmac at what I estimate to be about 10-15 MPH. Amazingly, I kept upright, up on to the island. Obvious damage was a bent front wheel rim (HED Ardennes) and, I believe, an unplugged front derailleur wire at the shifter. I rode the bike an additional three miles homes with no noticeable performance/riding issue.

What else should I look for in terms of possible damage? I’ve checked the frame for cracks and have found none but have not ridden the bike since for fear of some hidden break. The sound made when I hit the traffic island sounded like someone had hit my bike with a baseball bat—very disconcerting. I intend to bring the bike to a bike shop to take a look but would greatly value your input and advice.
— Rufino

Dear Rufino,
It sounds like you are doing the right things. Keep inspecting it and listen for new creaks and clicks when riding it.

Tapping on the frame along the tubes and joints with a coin to listen for abrupt changes in the sound and vibration quality of the clacking sound of the coin on the carbon is also a good idea.
― Lennard

Dear Readers,
In my response to Eric last week, I neglected to mention that the higher speeds of road bikes also work to cool the brakes faster as well. Of course, it is incumbent upon the rider to let off on the brakes intermittently to allow them to cool, rather than holding them on steadily so they continue to build up heat. And on extremely hot days like those we discussed in Oman, this would be even more critical.
― Lennard

Dear Lennard,
I believe the main reason rotors on road bikes are generally designed to be smaller than their MTB counterparts is the available tire contact patch. I think the additional braking power on tap with hydraulic calipers can quickly overpower the traction available and cause lock-ups and more skidding with hydraulic disc brakes. The more leverage the caliper has, the more exacerbated the problem becomes. As it is, it’s not hard to overpower the traction usually available with modern, half-decent rim brakes.

In essence, I think that the brakes are designed to be weaker for safety, as losing traction or going over the bars is far more dangerous than longer stopping distances. Boiling hydraulic fluid is akin to over-cooking your rim pads or carbon brake surfaces, so the risk is about the same there.
— Ante

The post Technical FAQ: A drivetrain hack, tire pressure, and road discs appeared first on VeloNews.com.

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