Re-surfacing brake tracks

Dear Lennard,
I have a set of Easton EC 90 carbon tubular rims that I use for ’cross. They are awesome despite being a little more than four years old and showing wear on the braking surface (they are not disc brakes). Can the braking surface be resurfaced? If so, how? Do you have any experience with this?

They’re great wheels that I am not able to replace at the moment and upgrading to discs is totally out of the question right now. It seems like ’cross can wear the surface down more than road use, so I would like to think there is a solution out there besides buying new wheels. But I am not aware of how it is all done. I would love any advice you could give!
— Dan

Dear Dan,
It had never occurred to me before to even think of doing such a thing. I am very interested to know as well and did some research on it. Unfortunately, the brake track cannot be resurfaced, if you mean by adding material, by any of the manufacturers I’ve contacted. Their responses are below. I also asked carbon-fiber repair firms, and only one of them would do it, and the others offered reasons for not doing so. See those responses below as well. If you were to somehow resurface it, I’m certain that it would void any manufacturer warranty you might have on the wheel.
― Lennard

From Reynolds:

Inherent in high-performance rims is the design concept for minimum wall thickness that will provide a “reasonable” life span. Unfortunately, this means that there is no additional sacrificial material that could be machined off in a resurfacing operation. In theory, ceramic could be deposited on the worn surface, and then ground smooth. As you may recall, I laminated a ceramic layer onto the surface of the carbon during the molding process (it was a production product for Lew rims), and also experimented with ceramic that was deposited after molding, and then ground smooth (never a Lew production process). For reasons not pertinent to this topic, neither is ideal as a current state-of-the-art solution for a new/production rim, however with significant resources (more cost than the cost of a new rim), a ceramic compound could be deposited to the braking surface of a worn rim and then ground smooth. This would be a solution/process for resurfacing a worn braking surface on a carbon rim.

Reynolds manufactures a ceramic brake track rim that is sold under the brand Pacific Rims, and it is sold as an OEM product to certain customers who request this brake track. The reason we do this is to avoid the hassle of needing to use a special brake pad. The ceramic makes the braking surface super durable and although it’s not marketed as a CX product, it would work well for that application. The down side of this rim is that the braking is not optimized for stopping power or heat-resistance, and it does not perform as well as our CTg laminate with the Cryo-Blue pad. It would, however, solve the problem Dan has experienced associated with CX use.
— Paul Lew
Director of Technology and Innovation Reynolds Cycling, LLC

From Zipp:

I can only speak for ours, officially. But they cannot. Most brake track surfaces, ours included, are integrally constructed and are not capable of being deconstructed to resurface them.
— David Ripley
Technical PR Manager
Zipp Speed Weaponry

From DT Swiss:

On the record, we do not recommend “resurfacing” of our carbon braking surfaces due to all of the variables involved. Especially given the brake track is both a structural and functional part of the rim. This is because we simply cannot vouch for the quality, materials used or the experience possessed by the facility or technician on a repair in the field.
— Matthew McClendon
Marketing/Account Executive
DT Swiss, Inc.

From ENVE:

No, there is not a process that can add material to a brake track after it has worn away. I mean, you could do it, but the structure just wouldn’t be there.

Riders would do best to just ensure they keep their pads fresh and clean/clear of debris.
— Jake Pantone
Marketing and Sponsorship Manager
ENVE Composites

From Easton:

During normal use, the carbon on the brake surface will wear. This typically takes longer than with aluminum if the correct pads are used, however weather has a big effect on the duration. There is no process for resurfacing the braking area of a carbon tubular or clincher rim.
— Adam Marriott
Product Manager, Easton Cycling

From Mad Fiber:

No one has commercialized brake surface renewal on carbon rims. Partly it’s the obvious trend we haven’t yet outgrown, that carbon rims should be extra light. So damage befalls them usually before brake track failure. Also, many carbon rims outlast the equivalent aluminum for braking, so the incentive is weaker. But probably the strongest trend is obsolescence. We’re learning so much, several year old carbon rims are relics. This won’t always be as the technology matures.

Today, there’s no agreement on resin systems for carbon bike equipment and that chemistry is key. Various systems are not compatible for a dozen reasons. You’d have to know everything proprietary about the original system to succeed. The very fact of widespread, successful carbon frame repair shows how much less is expected of them (gram for gram) compared to wheels and rims. You can often just layer it on thoughtfully and without regard for any thermal events. And the resulting weight increase is acceptable.

But I still dream of some sort of plasma/ceramic paint that fixes the worn brake track. We’ll probably all be switched to disks before that comes around.
— Ric Hjertberg
Founder, Mad Fiber

From Velomax:

I am assuming by “resurface” he means sanding down or otherwise abrading the existing surface to make it smooth again, since laminating a composite to an existing structure is beyond the experience of the average person.

The brake surfaces are intended to accommodate wear due to the natural abrasion of the brake shoes. For the most part, this wear is imprecise, so the laminate of the brake track is constructed with the knowledge that wear will occur. So it stands to reason that controlled wear, in this case intentionally resurfacing the brake tracks (by sanding them down), shouldn’t be any worse than brake shoe wear. But there are limitations.

Carbon fiber does not have good abrasion resistance, so the brake track area typically has a non-carbon fiber scrim (typically fiberglass) as its top surface. When you wear through this layer, your rim’s days are numbered. Also, any layup requires overlap of the plies, so in some areas of the brake track the abrasion layer scrim will be twice as thick where layers overlap. When you start to wear through the scrim, there will be areas of the brake track that are worn down to the carbon fiber, and other areas that are still scrim. The friction of the different materials will also be different, which could be one of the reasons that the user is experiencing uneven braking. So in this case, refinishing means removing all the remaining scrim so that the only thing that remains is the carbon.

At some point, the brake track is simply worn too thin, and the wheel is done. This situation is no different for an alloy rim. Also, at some point the rim is simply worn out, and needs to be replaced.
— Brad Hunter
Founder, Velomax

Answers from carbon fiber repair professionals
From Calfee Design:

Generally, no. Rims have the potential to become heated beyond the glass transition temperature of the epoxies we can use for repairs. This would cause the material to become soft and gum up the brake pads, potentially locking up the wheel, causing an accident. Having said that, a person could resurface it with epoxy but make sure to never let the rims get too heated while braking. Best to transfer the fancy rims to a disc compatible hub and never use rim brakes on them again. One should not use rim brakes on carbon rims unless you are prepared to replace them when worn out.
— Craig Calfee
Founder, Calfee Design

From Broken Carbon:

Unfortunately I can’t. I don’t know anyone that can, as a matter of fact. It’s just too hard to get the width uniformity required for consistent braking.
— Brady Kappius
Founder, Broken Carbon

From Spyder Composites:

Yes we do/have, but only if we can’t talk the customer into a new set of hoops through their LBS. The way I see it, if the owner is experiencing brake wear problems he is using the wrong pads, the wrong rims, or the equipment is past its useful life and he/she needs to treat themselves to a new set of wheels.

We do have a device similar to a truing stand we use to machine the brake surface before and after we coat the rim.
— Frank Moir, Owner
Spyder Composites

From Ruckus Components:

We used to offer this as a service but don’t anymore. It just turned out to be too much work on our end.
— Shawn Small
Chief Engineer
Ruckus Components

Disc/caliper brake combo

Dear Lennard,
With the trend toward disc brakes on road bikes, why bother with a disc on the rear? It would make carbon rims without special braking surfaces possible, but isn’t the vast majority of stopping power in the front? With front disc and rear caliper, people could retrofit existing bikes just by replacing the fork.
— Russ

Dear Russ,
You could run a standard rim brake on the rear and a disc on the front. That’s how mountain bikes used to be when disc brakes first came out — a V-brake on the rear and a disc brake on the front. Then you only buy one wheel, one brake, and the fork.
― Lennard

Feedback: Avoiding derailleur hanger damage when shipping a bike

Dear Lennard,
After having a handful of occasions where my hanger has been bent despite removing the derailleur, I leave the derailleur on the hanger but remove the hanger/derailleur combination from the frame. This eliminates the need to carry a DAG in your box.
— Darius

Feedback: Anti-seize lube

Dear Lennard,
I read about your pet peeve regarding copper-based anti-seize. I’ve been using moly-based engine assembly lube where anti-seize lube is needed. It works great and doesn’t have issues with copper flakes like other anti-seize compounds. You can pick some up fairly cheap at most auto parts stores.
— Kevin

VICENZA, Italy (VN) — Campagnolo has long been known for guarding its trade secrets fastidiously, and when it comes to seeing the workings of its factory, many sections for some time have been off limits to anyone outside of the company, and photography was strictly prohibited inside the production areas.

But a new spirit of openness has swept over the company as it hits its 80th birthday. Its directors recognize that the market is much different now than during the days when Campagnolo dominated the high-end bicycle component world. In this day of online social networking, a lot of interested bike riders are bound to appreciate the company opening up more to the public.

This October, anyone who has registered before the event fills will be able to get the weeklong Campagnolo Experience. This involves being immersed in Italian cycling culture, riding the roads that inspired company founder Tullio Campagnolo, and seeing the workings of the factory he started and that now is run by his son Valentino.

The Campagnolo Experience starts in Rome on Sunday, October 13 with the Granfondo Campagnolo Roma, in which riders will pedal past the Coliseum and through the Castelli Romani hills on roads completely closed to traffic. Then, along with Thomson Bike Tours, riders will head north for four days on a fully supported, 800-kilometer ride through the Apennines to Vicenza. On October 18, they will wander the hallowed ground of the Campagnolo factory floor.

Thing is, that experience is only open to 30 riders shelling out $3,000 each plus airfare. So I’ll share my recent factory tour with the rest of you.

This time, I was able to take photos in the factory, something I had not been allowed to do in over a decade, although there were still some sections I could not see, and some areas I could see but couldn’t photograph. In the mid 1990s when Campagnolo parts were primarily made of forged aluminum (forged outside by subcontractors and finished by Campagnolo) with steel or titanium bolts and pins, I was allowed to publish photos in VeloNews that I’d taken in the factory; I was not, however, allowed to see assembly of Ergo Power levers. But with the advent of carbon-fiber parts, Campagnolo closed the entire factory to photography and blocked visitor access to carbon-fiber production and research areas.

This time, I was able to see some carbon-fiber production, something that was not allowed when I last toured the factory in 2009. EPS (electronic) system components are made in Vicenza, but I was not allowed to see them being made, and carbon production was off-limits for photography.

Campagnolo claims to be the only global component manufacturer in the western hemisphere. Its sales have risen significantly for the past few years, despite a poor Euro exchange rate that punishes European producers. The growth can be attributed to pioneering 11-speed drivetrains, often beating competitors in weight, growing the Fulcrum wheel brand, moving aggressively forward with EPS electronic components, and following the popularity of gravel-road events with three complete triple-crank groups.

Seventy percent of Campagnolo sales are in Europe, but a 33 percent increase in 2011 sales in Japan promises to slightly shift that number. OE sales (i.e., for assembly on complete bicycles) account for 30 percent of the company’s sales.

Campagnolo has three factories: its original one on Via della Chimica in Vicenza, which employs 350 people, and two Romanian factories. MechRom 1, founded in 2005, employs 349 people, while MechRom 2, which opened its doors in 2011, has a 37-person workforce building carbon and aluminum wheels.

Like any factory making hardware, this one in Vicenza makes a lot of banging and whirring noises. The machines run 24 hours a day, with workers putting in three 7.5-hour shifts daily. There is a big difference in the machines, however, from my first visits there over 20 years ago.

In those days, Campagnolo did not make chains or stamp out its own cogs, so there were not the huge stamping presses or the completely automated chain-production lines that can be heard busily pounding steel and titanium and rapidly snapping pins into chains. Furthermore, rather than operators machining parts at small milling machines and having lathes peppered throughout the factory, super high-tech CNC (computer numeric control) machines now automatically crank out parts faster, precisely to the specifications programmed into them.

Central to the factory both in location as well as in importance is a test lab and quality control department, and these areas also have advanced greatly from the versions of 20 years ago. In there, engineers precisely measure adherence to specifications, and machines constantly drive wheels and drivetrains in all sorts of conditions. Test machines even repeatedly run the Campagnolo iconic corkscrew through its paces to make sure that it will hold up through a lifetime of wine drinking.

The EPS electronic group is tested at both low and high temperatures and in the wet. The tests ensure that it offers flawless performance at 14 degrees to 122 degrees Fahrenheit. The battery is tested to ensure that it holds a charge from -4 degrees to 176 degrees. Test machines simulate riding in water and mud, and electronic components must be able to run continuously for a week underwater before they pass inspection.

Campagnolo test engineers can mimic six months of riding on an entire bicycle drivetrain in only two days in the lab. The tests are entirely objective, and Campagnolo tests its own components as well as SRAM and Shimano components this way.

Campagnolo has built a number of data-recording bikes, and technicians compare six months of telemetry data from the bikes with perception data recorded by the riders of the bikes. The equipment records the bike speed and the positions of the derailleurs and front and rear hubs. Using the data, Campagnolo engineers built test machines to duplicate the conditions the bikes experience on the road.

A bike with data-acquisition equipment on board was ridden at speed on the cobbles of Paris-Roubaix. The data was digitized and those same conditions are simulated in the Campagnolo lab.

Campagnolo’s recently implemented “tribal marketing” approach attempts to connect people, their passion for cycling, and its brand together. Opening the factory to the press, OE manufacturers, distributors, dealers, and riders is part of that new corporate approach. May you be one of the fortunate 30!

Car exhaust heat and carbon wheels

Dear Lennard,
I’ve been an early adopter of discs for ’cross and every day commuting use — I ordered a XCR tubed ’cross frame with an ENVE disk fork not long after the fork was released. We do end up having our share of mud days in XC but also CX. I’ve consistently found the advantage in disk brakes in ’cross to be coming into a sharp u-turn or series of turns after a long straight, for example, reaching 40+ kph. I’ve seen guys on [cantilever brakes] pop after having to repeatedly close the small gap due to the braking differences.

I have ordered a couple sets of the new kettle carbon discs to try. One is for some ENVE tubulars that see daily use for commuting and training (challenge 27mm rubber), CX racing, and also XC MTB racing. The other set is for a MTB. But after reading your article, I may try them on my dedicated mud CX wheelset as they don’t seem to have many — if any — holes in them. They are pricey for sure but they may fit the bill for those using disks and racing often in the wet if they do in fact hold up.

I also thought I would let you know of something that happened this weekend as I haven’t seen or read anything about it. I put my bike on my rear rack because I had the kids in the car and couldn’t be bothered removing the front wheel. I took a short drive to my LBS as a bike needed a piston kit. It was a very hot day and the drive was about 20 minutes, with half at freeway speeds. Upon arrival at the shop, I found my ENVE UST wheels were cooked! I have an insurance claim in at the moment but with all the hype about the heat resistance of carbon rims, it seems they really aren’t that great. I’ve had many alloy rims in the same position on the same rack with no hint of damage and there was also no damage at all to the tire.

It was definitely exhaust heat on the front wheel, not impact damage from driving — the rear must have been far enough away to not get damaged. I spoke with ENVE about increasing awareness of the issue. I’m not faulting the wheel, just saying that with rear mount racks being ubiquitous, one doesn’t hear much or see warnings about the hazards of exhaust heat to carbon wheels.
—James

Dear James,
It never occurred to me to be concerned about overheating carbon rims by hanging them in front of a car’s exhaust pipe. So here’s the obligatory warning — be careful about hanging a bike with carbon rims on a rack mounted on the back of your vehicle. Make sure that the wheels are far from the exhaust pipes!
― Lennard

Short vs. long braking: Companies weigh in

Dear Readers,
In my April 30 post, I answered a question from John about short vs. long braking and latex or butyl tubes for mountain riding on carbon clinchers. I promised to get more feedback from manufacturers about it. Survey says: I was right about preferring shorter, harder braking, and I was wrong that the type of inner tube is unimportant. I think all of the answers are interesting, and each looks at it from a slightly different angle. See below.
― Lennard

From Zipp:

For any given stop, say coming to a stop at the bottom of a hill, a stoplight, etc., there really isn’t much difference. You have to bleed energy and doing it over a short time or longer time doesn’t change the temperature much by the time you stop. So for 98 percent of riding, the answer is that it really doesn’t make much difference.

However, on a long or tricky descent, giving the rims and pads periods of cooling is very beneficial to keeping the system temperature under control. Most important is to not drag the brakes for prolonged periods of time as this continually heats the rim, pads, tube and tire. In our internal testing, we have achieved surface temperatures approaching 700 degrees Fahrenheit after 5-6 minutes of prolonged heavy braking (simulating a 300-pound guy descending a 20 percent grade for 5+ minutes, so not a likely real world situation). Releasing the brakes for even a few seconds can reduce the temperatures on the rim by over 100 degrees, whereas keeping the brakes applied, even lightly, will continue to heat the system. Again, whether you begin to slow 75 meters before the hairpin or 60 meters before isn’t very critical, but riding the brakes the entire way down the mountain isn’t good for any of the components in the system.
—David Ripley
Technical PR Manager
Zipp Speed Weaponry

From DT Swiss:

In our experience, the shorter, more aggressive braking method is preferable. While the heat at the rim/pad interface will be higher during braking, the additional time between brake applications will allow for more cooling of the rim as compared to a prolonged braking method. Put another way, when brakes are used for a longer time at lower power, there is less time for the rim to cool off in between brake applications.

Decelerating from one given speed to another is going to require equal energy input, regardless of braking method. However, having an increased cooling period between braking will let the system cool off more, decreasing heat build up.

Since we are talking about carbon wheels specifically, it is important to keep other elements in mind. Firstly, tire pressure and size play a significant role here. If a rider knows he or she will be doing a lot of descending, it may be a good idea to lower tire pressure a bit before the ride. As rims heats up, tire pressure will increase, possibly past the recommended limits for the rim or tire. Also, a larger tire at a given pressure will exert more outward force on a rim, so it’s key to drop pressure a bit as one increases tire size. Finally, latex tubes are far more susceptible to flatting from heat, often without the tire ever coming off the rim (see Tony Martin’s infamous flats at last years TDF), and as such should never be used in our carbon wheels (I think other manufacturers have a similar recommendation).
—Steven Sperling
DT Swiss, Inc.

From Hed Design:

We have been measuring rim heat up for a while now. The worst case, this is real world with a temperature reader, is a long, feather-type braking. This warms up the rim [more] than a hard pulse stop — it spikes an already warm rim. Carbon is a good insulator, so when it can’t dissipate the heat, it slowly collects it and holds it. FYI — we cannot get an alloy rim to heat up over 250 degrees Fahrenheit, carbon rims we’ve gotten over 450 degrees. We spent a couple of years getting our carbon brake walls to take the heat, using high temp resins and a higher curing progress.

The next problem is solving the rubber in the tire and tube from degrading. I think the rubber used in tubes and tires is vulcanized at around 320 degrees. So when tires and tubes see more than this they start to break down. It might take repeated elevated temps to do this, the first hard stop may not, but over cycles the tube can start to fail, even though the tire hasn’t. My advice, if you know you have spikes of heat into your carbon rims, is to at least replace the tubes and inspect the tire bead to see if it has become soft, gummy, or degraded and replace if needed. We are still working on the problem.
—Steve Hed
Founder, Hed Design

From Reynolds:

The worst type of riding style for carbon wheels is the “rear brake dragger.” Prior to our CTg laminate, the typical carbon rim heat failure was almost always the rear wheel; rarely did we ever see a front wheel with heat failure. Now, with the CTg laminate we don’t really get many heat failures at all, not even rear wheel failures.

To answer your question directly … Yes, for sure, shorter, more powerful braking produces less heat build-up than prolonged braking. We’ve known this for a long time to be the case.

I’ve had similar discussions with other manufacturers and we all have the same experience. I reference a conversation with Jorg Ludwig not too long ago when he was telling me that he, Mario Cipollini, and other pro riders never had a heat failure with their team’s superlight carbon wheels, but that in the commercial marketplace his experience is the same as mine, that the heat failures with those same wheels are mostly rear wheels as a result of dragging the rear brake.
—Paul Lew
Director of Technology and Innovation Reynolds Cycling

From ENVE Composites:

Heat buildup in the rim will have more to do with average speed during the duration of the descent than the method of braking. For the duration of a descent, coasting and then braking into the corners usually results in a higher overall average speed. Higher average speeds result in lower rim temperatures because of the following.

- At higher speeds, much more energy is dissipated by aerodynamic drag than at slower speed. Higher speeds shift the balance of energy dissipation to aerodynamic drag, and away from the rim and brake pad.
- Convection of heat off the rim is accelerated by the higher air speeds.

One scenario where the braking style will change heat buildup in the rim, even if the same average speed is maintained:
-Dragging brakes tends to glaze pads, and glazed pads don’t shed material under braking. Shedding of pad material is of significant benefit to keeping the pad/rim system temperatures under control. Glazed pads run significantly hotter than pads that haven’t glazed.

We test braking of our wheels at a steady speed and power, as that was what we found to be the riding style that resulted in the highest rim temperatures during ride testing.

Regarding internal rim temperatures:
-Deep rims tend to run cooler than shallow rims. The deep sidewalls act as a heat sink, drawing heat away from the brake track.
-In our testing, aluminum rims run hotter internally than carbon.
-Latex tubes are more sensitive to heat than butyl. Under prolonged braking, any slight irregularity in the tire bed (like the edge of a rim strip, or the transition from tire bead to tire bed) may result in sudden deflation of the latex tube. We’ve seen this in both carbon and aluminum rims. Latex may work really well for riders who aren’t faced with long descents, but we can’t say that they are safe for all use scenarios, so we can’t recommend using latex tubes.
—Brent Pontius
Test Engineer
ENVE Composites

From Mavic:

I double-checked with our R&D team. The heat would be the same in both cases.

The difference is that in shorter braking, the temperature will not remain high for a long time. With prolonged braking, the temperature remains high for a longer period of time and is what causes issues on carbon rims, inner tubes, brake fluid, etc. (depending on what brake system you use).
—Maxime Brunand
Mavic Road Product Line Manager
Annecy Design Center, France

From Campagnolo:

The longer the brake pad is in contact with the braking surface, the more friction will be transferred to heat. Even a dragging/rubbing miss-aligned brake caliper can cause heat build up. On long descents, dragging or “feathering” the brakes actually causes more heat build up than quick, short uses.
—Daniel Large
North America Technical Service
Campagnolo North America Inc.

From Shimano:

Steady drag of brakes produces more heat buildup, because shorter, high-intensity braking allows heat dissipation during non-braking time.
—Wayne Stetina
VP R&D
Shimano American

From Dash Cycles:

For slowing down on descents, I always recommend against prolonged braking. It can depend on the quality of the rim and brake pad, but shorter, more powerful braking will typically produce less heat buildup.
—Tom Guerin
Founder, Dash Cycles

Named after an uphill Strava segment on Norcom Road near Fuji’s Philadelphia office, the Fuji Norcom Straight aero bike looks fast standing still and feels fast when riding it. With the slogan, “When Seconds Matter, Fit Comes First,” Fuji is staking its claim that the bike fits a wider range of body sizes than any other aerodynamic “superbike.”

Steven Fairchild, the designer of the Norcom Straight, holds the current record on the Norcom Straight Strava section. He and his design team have been working on this bike for three years. They have spent countless hours in the A2 wind tunnel in Mooresville, North Carolina dialing in the aerodynamics of it, and then working out the positioning options to fit a wide range of riders without throwing out the aerodynamics with the bath water that has absorbed countless more hours.

Aerodynamic design

On their first day in the wind tunnel on this project, Fairchild had a modular prototype with interchangeable sections so that he could quickly make 24 different configurations of the frame. Once the wind tunnel results had narrowed it down to a single fastest frame shape, he taped dozens of short sections of yarn to the frame. The next day, he watched in the tunnel to see which pieces of yarn were running straight, indicating smooth, fast airflow, and which pieces were fluttering, indicating turbulence.

The next time he was at the wind tunnel, he brought a plastic prototype that he’d refined to smooth the airflow in those fluttering areas. He particularly worked on the airflow from the fork, over the hidden brake and onto the down tube. A further iteration was a model with a narrower head tube, which Fairchild found to speed the bike up in the range of zero to five-degree yaw angles in the wind (Fuji tested every prototype from zero to 20 degrees of yaw).

This back-and forth process continued until he was satisfied with the gains over Fuji’s previous most aerodynamic bike, the D-6. Fairchild claims a 7-16 watt reduction (depending on wind angle) in the power required to propel the Norcom Straight at 30 mph vs. the D-6. (At 30 mph, 11 grams of drag is roughly equivalent to a single watt reduction in power required.) Fuji’s superstar triathletes Cam Dye and Sarah Haskins dialed in their positions on the bike in the wind tunnel as well. Haskins, who was three months pregnant at the time, proclaimed herself to be “the most aerodynamic pregnant woman in the world!”

The seat clamp is very clean and aerodynamic, with an internal wedge securing the aero seatpost by means of a tightening bolt whose head is flush with the top of the top tube. Because of the thin profile of the seatpost, an internal Di2 battery is not yet an option; the Shimano Di2 or Campagnolo EPS battery mounts to tapped holes on the back of the seatpost.

The stem is the same width as the top tube and fits into a notch in the head tube to smooth airflow. The cables (and/or electric-shift wire) drop into the top tube in one of two options of smooth wire ports. The frame has complete wire guiding inside, so installing a cable is a snap; just push it in until it pops out at the back.

The bike comes stock with a UCI-compliant Oval 960 base bar. The Oval 970 base bar with split “Jetstream” technology has six percent lower drag than the 960 and is not UCI-compliant. The stem has a snap-on aerodynamic cover for the front cap.

The pointed nose on the head tube is hollow inside, allowing the front brake cable to run straight down through it. The cable then goes into an open and hollow fork crown and takes a 90-degree bend forward toward the brake. Fuji has come up with its own forged aluminum linkage to powerfully apply the aerodynamic TRP TTV front cantilever V-brake, which is hidden in a pocket behind the fork. The rear TRP TTV cantilever V-brake pivots on the chainstays and is concealed under and behind the BB86 bottom bracket by a screw-on plastic cover.

Bike fit

The Norcom Straight comes in five sizes: 49, 51, 53, 55, and 57cm. This did not seem like a lot of sizes or a wide range to me, and with my 6’5” height, I was having a hard time imagining myself fitting on the 57cm. However, I rode Matty Reed’s 57cm Campy electronic Fuji and found the fit to be perfect. Reed and I are virtually the same size, and I could just hop right on his bike and ride it as he had it set up. The smaller end is more of a challenge yet, but Fairchild claims that the fit small riders get on the Norcom Straight is superior to any other bike of similar aerodynamics. Coupled with Reed’s Dash Cycles Stage.9 saddle, this was the most comfortable ride on an aero bike I’ve maybe ever had.

Key to this fit is 135mm of cockpit height adjustability. The forged aluminum Oval 760 stem comes in six lengths, from 80mm to 130mm, and either 8- or 17-degree flipable rise. The 135mm height difference is from a -17-degree slammed stem to the stem flipped up to a +17-degree angle with 50mm of spacers under it (in which case the spacers, but no longer the stem, nestle into the cutout in the head tube.) The stem fits a standard 31.8mm handlebar diameter.

The saddle can move over a wide range, too, both up-down and fore-aft. There is a full 180mm of vertical seatpost adjustment on the 400mm-long aero seatpost. However, getting the lowest available positions in this 180mm range will require cutting up to 60mm off of the end of the seatpost, due to the curve in the seat tube around the rear wheel. There is a 70mm range of fore-aft adjustment on the seatpost as well, offering effective seat tube angles from 74 to 81 degrees (the frame’s seat tube angle is 78 degrees on all sizes).

The 42cm-wide carbon base bar, be it the 960 or the 970, offers three different width elbow-pad mounting positions. There are four riser heights from 5mm to 20mm and five elbow pad rotational positions. Three extension bends are available: ski, S, and straight; the extensions clamp into a forged aluminum clamp at the back of the base bar with a long split requiring low tightening torque to hold the extension in place.

Mechanical efficiency

The front end and the fork are each molded in a single “monocoque” piece, and both the down tube and the fork legs have an internal stiffening rib (a crosswise wall) running down the center of them. These ribs and oversized tube sections, along with the wider BB86 press-fit bottom bracket shell, result in a claimed increase in stiffness of 26 percent at the bottom bracket and 20 percent at the head tube relative to the D-6, while being 200 grams lighter and having better aerodynamics. The chainstays and seatstays are molded separately and are bonded to the front end and the dropouts.

The dropouts are vertical and slide back and forth to offer 9mm of fore-aft adjustability secured by a bolt. These vertical dropouts make wheel changes a snap — virtually the same as on a road bike, as opposed to the struggle one can encounter changing a wheel on the rear-entry dropouts so common on aero bikes.

The fork and rear end fit wheels with rim widths up to 28mm wide as well as the Zipp Sub-9 disc, which so famously was too wide to fit in the Cervelo P4 at its introduction at Interbike in 2008.

There are two frame models coming out of the same Norcom Straight molds, namely models that start with a “1” in the model number and which have higher-modulus carbon, and lower-modulus models whose model numbers begin with a “2.” The second number of the bike model designation indicates the components specifications. There are five total models, ranging from the $7500 Norcom Straight 1.1 with Dura-Ace 9070 Di2 11-speed and Oval 981 deep carbon clinchers, to the Norcom Straight 2.5 at $2300, featuring Shimano 105 rear/Tiagra front derailleurs and Oval 327 shallow-section aluminum clincher wheels.

The three years of sweat equity seem to have paid off. I was very impressed with the ride. It certainly felt fast in the aero bars on the flats, downhills and gradual climbs, and it was very stiff, even when sprinting up one of Boulder’s steeper hills. Regarding a bike switch from Kestrel to Fuji for this season, Dye said, “I had such a good season last year, I was reluctant to change anything. But this bike is way faster!”

Said Stephanie Genuardi, Fuji’s marketing communications manager: “This is one of the biggest projects ever for Fuji.” That’s a pretty strong statement for a company that has been around since 1899.

IT band stretches

Dear Lennard,
I was wondering if you had a picture to describe the stretch you wrote about in this story.

I also have had Iliotibial band issues and would love to reduce their occurrence.
—Ian

Dear Ian,
Here you go; thanks to my wife for taking the photo.
―Lennard

Dear Lennard,
The recent letter you received from Daniel regarding stretches to avoid pain from ITB syndrome caught my eye, having suffered the same problem. I think a foam roller is the most effective stretching method, but it must be done in conjunction with exercises to address the root cause of the problem — a strength imbalance between quads and hip flexors responsible for lateral stability.

I often have trouble if I’ve had to stop riding for more than a week due to illness or the need to travel. I think I lose strength in my hip flexors faster than in my quads during periods of inactivity. When I return to cycling, if my hip flexors are weak relative to my quads, my pedaling technique gradually worsens as I fatigue. At the start of the ride, my knees piston up and down in a fairly straight line, but as I tire, my knees gradually follow a more elliptical pattern. My ITBs are obviously working overtime to maintain lateral stability in the absence of help from my hips and they tighten up.

I’m told by my physiotherapist that the gluteus medius is the main culprit. He prescribed one-legged squats to strengthen and “activate” the muscle, which I understand to mean re-teaching the nervous system to recruit the use of that muscle more effectively. I start the exercise by holding onto the mantelpiece to keep balanced and progress to a free-standing position. I perform three sets of squats to failure using just my own body weight and try hard not to wobble from side to side on the way up and down. Another exercise I use to strengthen the gluteus medius is the “clamshell.” This is done lying on your side, heels together and raising and lowering your knee vertically. The goal of course is to get strong and develop a pedaling style like Cancellara displayed during the final 10 miles of the Tour of Flanders — that guy has some serious glute strength and endurance!
—Paul

Foam rollers

Dear Lennard,
Here’s a travel-friendly foam roller for you. A bit pricier than Ben Chaddock’s PVC pipe, but not nearly as painful.
—Michael

Dear Michael,
That is better than the cut-down foam roller I used to travel with. I just cut a regular three-foot roller in half, and it worked okay, but I kept getting pulled aside at the security check in Frankfurt to get it tested on some gadget in the back room (I carried it on, so I could use it between flights). I’ve had the same thing happen when I carried on a bike helmet in Frankfurt …

That Grid Mini foam roller would take up less room and allow other items to be stuffed inside it, although it’s a bit short; I’d have to change my rolling technique!
―Lennard

Are o-rings necessary?

Dear Lennard,
When I put on a new chain I remove the jockey wheels and clean them. The inner wheel (one closest to the cogs) of my 10-speed Ultegra derailleur has o-rings and apparently the last time I did the cleaning I didn’t get one of them seated correctly. So this time I found that it was mangled. When I asked at my LBS, the mechanic said the rings weren’t necessary and that they have on occasion simply removed them. I figure the rings must be there for a reason. What do you say?
—Chris

Dear Chris,
Yes, they’re there for a reason, namely to keep grit out. But if you keep your jockey wheels clean and lubed, that’s not a big issue, and they’ll run faster without them. Or you can swap them out for a different model.

Even Wayne Stetina, Shimano R&D director, wrote to me, “I hate the seal drag of o-rings and always remove from Ultegra / XT. Retrofit DA / XTR cartridge bearing lower pulley?”
―Lennard

Which type of air is best for bike tires?

Dear Lennard,
I just read your recent article on VeloNews about tire inflation gases. A little background on myself, I worked for almost 10 years as an engineer with professional motorsports teams here in the United States. A few years ago there was a big stink about Ferrari’s Formula 1 team filling their tires with CO2, so I did a bit of research and experimentation into the reasons for using different gases to inflate race tires.

The prevailing opinion at the time was that nitrogen was better to use in our tires, because as the tires heated on the track, the pressure rise was less than for normal compressed air. Less change in pressure per degree temperature rise (dP/dT) means less change in tire behavior for temperature change. It became especially important to reduce dP/dT for caution periods during races and putting new sets of tires on the car — the faster you could get the tire pressure to reach your target, the faster your car got up to speed. For an example, we would set the tire pressure at, say, 21psi cold, with a goal of reaching 25psi “hot” (at roughly 200degF).

In our research, we found that the mantra of “nitrogen is better than plain compressed air” is only partially true. If you can completely dry plain compressed air, it actually has a lower dP/dT than nitrogen. Not by much, but it is better. The problem is that your typical compressor — or hand pump, in the case of bike tires — compresses the partial pressure of water in the air along with all the air. The water increases the dP/dT of the air.

As for CO2, it does have a significantly lower dP/dT than nitrogen and compressed dry air. For my example before of a goal of reaching 25psi “hot,” we could start with a cold pressure of, say, 23psi instead of 21psi. For our application, this was a big change, and a major improvement. My experiments backed up all of my theoretical results for behavior of these gases.

As a side note, in a purely theoretical sense, one of the best gases to use to reduce dP/dT in a tire would have been acetylene. However, as well as it would work, it would tend to make slow leaks a bit more … explosive.

What does this all mean for bike tires? Probably not much. I don’t see bike tires raising temperature nearly to the extent that we saw race tires spinning at 235mph. I’d be more worried about the temperature of the gases you’re putting in the tire initially — if you’re filling a tire from a compressed tank, there will be some expansion cooling happening to the gas as it enters the tire, which will cause the pressure to rise as it warms up to roughly ambient in the tire (think of how cold CO2 cartridges get when you release a lot of gas from them). I use whatever is most convenient!
—Enzo

Dear Enzo,
Amazing coincidence that you worked in motorsports and have that name!

I saw nitrogen used as an inflation gas at the Sebring car racetrack to keep the humidity in the tires lower.

We had a discussion four years ago about how CO2 bleeds out of bike tires faster than air. I wonder if that happens in car tires? It seems hard to imagine that Enzo Ferrari would use it if it did.
―Lennard

Since we got a foot of snow here in Boulder every week in April and the first week in May as well, I might as well publish some feedback on the story about cycling in cold weather I wrote in March, when I thought we were about done with cold weather.

Flawed science?

Dear Lennard,
I have always enjoyed your articles, particularly the emphasis on separating science from marketing and fiction.

Unfortunately, your article titled “Technical FAQ: Why is riding in the cold so hard?” misses the mark, and provides physically incorrect results and analysis from your “experts.”

The main point of concern comes from Chet Wisner stating that, “drag increases by the square of the speed. The ratio of the squares of 21 mph and 20 mph is about 1.10. So, this increase would have the same effect on the drag you are pedaling to overcome as the 50-degree Fahrenheit temperature difference.”

This is a flawed statement. While yes, the drag varies as the square of the speed, it is not correct to compute the velocity by equating the drag.
The power to propel the cyclist is what should be compared. That is, how will the velocity vary between two days if the power is maintained constant?

Since Power = Velocity x Drag, the power increases with the cube of the velocity. As stated in the problem, assume a cold to hot density ratio of 1.10. A rider putting out the same power would not increase their speed by 1.1^(1/2), but instead, by 1.1^(1/3). That is, the importance is exaggerated with Chet Wisner’s approach. Using his approach, 20 mph on a cold day equates to 20.98 mph on a hot day with a 10% decrease in density. However, the actual value computed will result in a speed increase to 20.65 mph (see page 4 of attached calculations).

Len Brownlie (who you quoted earlier in the article) understands this point, noting that you can compute how much longer it will take for “the same cyclist, generating the same power,” to complete a 40km course on a cold day.

Unfortunately, his actual calculations are wrong. Any undergraduate engineering student who has taken a fluid mechanics course can quickly work through the calculations for the prescribed density variations (see attached pages 1-3). Assuming on a hot day a rider does 40 km in 58:37, with the values given in the article, the average power can be computed to be 199.65 watts. Now, repeating the calculation for the cold day, solving for the average speed at the given power, and then determining the time to complete 40 km at the computed average speed reveals a final time of 60:45, not 60:00. I’m sure you’ll agree that 45 seconds over a 40 km distance is pretty significant.

Even his computation of “performance decline” is incorrect. Using his own wrong numbers, the percent decline in performance (based on time) is 2.36 percent, not the stated 2.77 percent. The actual performance decline, using the time difference between 58:37 and 60:45 is 3.64 percent.

In summary, I applaud you for your efforts to bring the scientific side to cycling, but I implore you to be more careful in your use of “experts,” or incorporate better editing to avoid simple mistakes such as these. The only thing worse than justifying performance decisions based on anecdotal evidence is to base them on misleading and inaccurate scientific decisions.
—Byron D. Erath, Ph.D.
Assistant Professor
Clarkson University Department of Mechanical & Aeronautical Engineering

Dear Lennard,
In your VeloNews article from March 12, you quote two readers that indicate an increase in air density of 10 percent is equivalent to an increase in speed of 5 percent. This is correct for the force but it is not for the rider’s heart. What the rider feels is the required power. The power is proportional to the force multiplied by the speed with respect to the road, thus the air drag power required is proportional to the relative air speed cube. An increase in air density of 10 percent at 20 miles an hour in a no wind situation is equivalent to an increase in speed of 3.333 percent (10/3) or 20.7 miles an hour.

It is also equivalent to riding at 20 miles an hour in a 1 mph head wind.

P.S. Your technical articles are gems.
—Pierre

The first time I ever spun a Tiso full-ceramic-bearing jockey pulley was at Interbike a couple years ago. I was amazed at how I could flick it with my finger and it would spin and spin and spin and spin some more. It was amazing. I’d never seen a jockey wheel do anything of the sort before.

Full-ceramic bearings have ceramic balls as well as ceramic inner and outer races. This is in contrast with “hybrid ceramic” bearings (common in high-end hubs and bottom brackets), which have ceramic balls and steel inner and outer races. The latter can of course still rust, and they require good seals and lubricant to prevent grit from getting into them and scoring the steel races. The grease and the seals definitely create drag, and there is no way the Tiso pulleys could spin that long and fast unloaded if they had seals and grease.

The ceramic parts in full-ceramic bearings are purportedly so hard that grit caught in them eventually becomes crushed or ground up! Presumably this would not be the case if were to you ride your bike inside a diamond mine, but out on the street, they should be harder than the grit that might contaminate them.

The Tiso full-ceramic-bearing jockey pulleys have no cover seal whatsoever over the balls. When I got some for my cyclocross bikes, their distributor, Albabici, told me not to worry about them being open to the elements and not to lubricate them at all. I have not.

After using the Tiso full-ceramic-bearing jockey pulleys in the mud and grit in cyclocross all season without cleaning or lubricating them, I fully expected them to become as resistive to turning as standard bushing-type pulleys. But I noticed during the season that whenever I pulled the chain off and spun them, they still spun better than any other jockey wheel I’d ever had.

Naturally, I wanted to test them for frictional drag. Friction Facts in Boulder is the perfect place to do it, so I headed over there with a pair that had taken a pounding and lots of washings all cyclocross season.

The last time these particular jockey wheels had been used or washed was at cyclocross nationals in early January. All season, I never put any lubricant on them, and I never cleaned them other than with a hose or a pressure washer while washing the entire bike. After I removed them from the bike, Friction Facts founder Jason Smith rinsed both of the pulleys under the faucet, spinning them while the water was flowing. He allowed them to thoroughly dry in front of a fan for six hours; then he formally tested both of these used full-ceramic-bearing Tiso jockey wheels, as well as a new one, on his Reactive Torque Pulley Tester (RTPT).

We compared the results on the used pulleys with the results on a new full-ceramic-bearing Tiso jockey wheel. The results are as follows:

New Tiso: 0.016 watts
Used Tiso No. 1: 0.042 watts
Used Tiso No. 2: 0.027 watts
Total power loss for the pair of used Tiso jockey wheels: 0.069 watts.

Here is a description of the test apparatus and protocol: friction-facts.com/equipment/derailleur-pulley-efficiency

The three graphs at the top of this page show the test results in watts for each of the three pulleys. The spikes on the screen prints are from Smith setting up the pulley and attaching the load to the strain gauge. The stable line on the right hand portion of the screen is the pulley reading.

I was privy to a jockey-wheel friction test that Friction Facts performed a number of months ago on a whole range of pulleys of various brands and models. In comparing with those results, I could see that my used, abused, and not lubed Tiso full-ceramic jockey wheels, while exhibiting much more drag than they had when new, still would have placed in fifth place, behind the new Tiso full ceramic and three others. They still out-performed 16 other new jockey wheels, some of them by over a watt per pair! I’d say this is really good, considering a season of racing and no seals and no lube. However, this is a subjective opinion. It sure was nice never having to do any maintenance on them, though! I usually dismantle, clean and lube my bushing-type jockey wheels every couple of months.

If you want to see how your jockey wheels stack up, you can purchase Friction Facts’ test results on 19 different derailleur pulley models for five bucks. Given the cost of some of these high-end wheels with ceramic bearings, that seems like a modest investment indeed before making a pulley purchase.

Carbon clinchers for heavier riders

Dear Lennard,
I am considering purchasing a full carbon wheel set, the Bontrager Aeolus D3 5. My concern is with the structural integrity of this wheel, seeing that I am 6 feet and 275 pounds, and also the braking/stopping performance.
— Richard

Dear Richard,
If I weighed 275 pounds, you would not catch me riding any carbon clincher wheels unless I were to ride them only on flat and rolling terrain. I think that because of heat developed during braking, riding a carbon clincher at your weight on mountain descents would be ill-advised.

And while the wheel has no weight limit and has a wider spoke bracing angle for stiffness than most wheels, my experience with riders your weight (my frame building business brings in lots of riders in the 275-pound range) is that wheels not specifically built for riders of your weight will develop fatigue problems within a year. Aluminum rims under heavy riders usually develop cracks at each spoke nipple on the rear wheel. On carbon wheels, spokes often break.

It’s an expensive wheelset, and unless you buy an extended warranty on it, I wouldn’t recommend the investment.
― Lennard

Late vs. gradual braking to prevent blowouts

Dear Lennard,
There has been much talk recently about the potential for heat-related blowouts with carbon clincher rims. While I have never had this problem myself, and have never heard a first-hand report of such an occurrence, I remain concerned. With the advent of SRAM’s hydraulic rim brakes, the potential for heat buildup seems even worse. My question is whether a very late and powerful braking action or an earlier, more gradual braking action will control heat buildup better. I will be doing a seven-day race through the Alps this summer and I’d like to be as prepared as possible for the notoriously steep (upwards of 22 percent), twisting descents. Also, are latex tubes any more or less susceptible to heat?
— John

Dear John,
My experience with doing a lot of testing of carbon clinchers on Flagstaff Mountain above Boulder is that shorter, more powerful braking produces less heat buildup than does prolonged braking. I’ll ask around more about this, because it’s a very good question.

The inner tube type is irrelevant; the tire only explodes because the tire bead blows off the rim when it gets hot enough, and no tube could hold the pressure once it’s no longer constrained within the tire.
― Lennard

Carbon tubulars vs. clinchers

Dear Lennard,
Would please give a brief explanation for the advantages and disadvantages of carbon tubular and clincher wheels? Is there more to it than the weight savings of the former and the easy flat-fixing of the latter?
— Sam

Dear Sam,
The carbon tubular rim is lighter due to the lack of bead walls. The tires corner better because they are round in cross section rather than lobe-shaped like a clincher. They are usually a bit lighter as well, having no beads and being able to use a lighter inner tube. For events and road conditions that warrant it, high-end tubular tires can generally be inflated to higher pressures than clincher tires of the same size. They are harder to pinch-flat than a clincher (due to lower, more rounded rim walls and tougher latex inner tubes). Tubulars are safer to ride when flat, as they are still glued to the rim, whereas a flat clincher can come off of the rim. And unlike a clincher where higher pressure in the tire applies higher outward pressure on the carbon rim bead walls, the tire pressure in a tubular tire has no effect on the rim (other than to compress it uniformly radially inward, thus reducing spoke tension slightly, something that happens with all tire types).

The disadvantage of a tubular is cost and the time and skill required for gluing it on. With enough braking heat, the glue has the potential to melt and allow the tire to come off (remember Joseba Beloki’s horrific crash?).

Clinchers are quicker to install, the tires are generally cheaper than tubular tires, and flats usually require only replacement of the inner tube and not the entire tire.

Clincher rims are heavier, and clincher tires are also a bit heavier than tubulars of similar casing and tread. While heat buildup in any clincher rim can be an issue during extended braking (see the melting glue problem mentioned above), it’s more of an issue with a clincher. The latest carbon clinchers from top brands, when coupled with the brake pads recommended by the manufacturer, are not likely to fail in this circumstance, but many carbon clinchers in the past have done so. Carbon is very strong under tension but not under compression, so asking it to form a rim wall capable of constraining the pressure of tire beads trying to push it outward is a big ask in the first place. Couple that with the fact that at some temperature, any resin holding the carbon matrix together will soften, and you can have rim walls that fold out like limp taco shells under hard braking. Again, this is a thing of the past for the top brands with the correct (and heavily studied) brake pads under riders who are not beyond a certain weight (and this weight will depend on the rims, braking style, the road steepness and curve sharpness, and the ambient temperature).
― Lennard

Tire pressure minimums

Dear Lennard,
I read on Velonews that the Paris-Roubaix riders used 60-90 psi in their tubulars. Is there a safe lower limit for clinchers?

With 23C tires, I would run 90 up front and 105 in the rear. I was trying to go as low as I could without risking a pinch flat. Now that I’m on 25C tires, I would like to go lower. I’m running 100 in the back and 85 up front right now. I like the way the front feels with the lower pressure, and wondered if I could safely go any lower? Is there a point where handling or safety might become an issue?
— Steve

Dear Steve,
It of course depends on rider weight and riding style (whether you un-weight the bike over bumps, etc.). And the bigger the tire, the lower the pressure you can get away with.

Besides the pinch-flat issue, it’s pretty easy to dent a clincher rim (which means it cracks and is broken, since carbon does not bend). So you don’t want to risk running it low enough to do that.
― Lennard

Campy EPS shifting problems

Dear Lennard,
I just had Campy Super Record EPS installed on my Specialized Roubaix. I am having trouble with shifting from the small ring to the big ring. What adjustment should I make? And when I shift to the smallest cog in the back with big ring in the front, there is some chain rub on the FD? Is that normal?
—Joe

Dear Joe,
No it’s not normal; your front derailleur is out of adjustment. It is not moving far enough outboard, which is causing both of your problems. Here is how to adjust it:

1. Shift to the inner chainring and the largest cog.

2. Get into adjustment mode by pressing both mode buttons —one on each lever behind the thumb lever on the inboard side — for at least six seconds; the LED on the EPS interface (zip-tied to a front cable or rubber-banded around the head tube) will glow blue.

3. With the LED glowing blue, bump whichever front shift lever is necessary to move the front derailleur the direction you want. Hold that lever until the front derailleur’s inner cage plate is 0.5mm from the chain. Holding the left thumb lever down gradually drives the inner front derailleur cage plate away from the chain; holding the left finger lever inward gradually drives the inner front derailleur cage plate toward from the chain (I’m sure that this second one is the adjustment you need to make). That’s all there is to do; there are no limit screws or other front derailleur adjustments.

4. Touch the left mode button to memorize the setting; the LED will flash blue and then turn off after a few seconds. If it doesn’t turn off, hit any mode button again to make sure it is out of standby mode (LED off).
That ought to do it. Ride and enjoy.
―Lennard

Campy EPS with mechanical

Dear Lennard,
I’ve been a long-time Campy devotee and have 10-speed Record on three bikes. I want to install Record EPS but I hate the idea of spending so much money and abandoning a perfectly good Record group. So, can I keep my 10-speed drivetrain and mate it to EPS electronics (derailleurs, shifters, etc)?
—Doug

Dear Doug,
What do you mean by drivetrain? The only thing you could use of your existing drivetrain is the crankset, and it will probably work OK, but not as well as an 11-speed crank. Everything else would either be electronic components or 11-speed ones, so you’ll need a new chain, cassette, front and rear derailleur, and shifters.
―Lennard

Replacing Dura Ace chainrings

Dear Lennard,
I have a Giant TCR SL 0 with Dura Ace 9000. The crankset it came with is 53-39. We are travelling to France soon with lots of climbing, so I want a compact crankset. I understand I can replace the front chain rings and leave the existing spider to change to a compact set. Do I have to change both front chainrings to 50/34? Or can I leave the 53 and change the 39 to a 30 giving me 53/30?
—Chris

Dear Chris,
Dura-Ace 9000 uses the same bolt circle diameter for compact and traditional double chainring pairs, so your one crankarm fits all chainring sizes. However, these are the only sizes Shimano offers in that four-arm design: 50-34T/52-36T/52-38T/53-39T/54-42T/55-42T

No, you cannot mount any smaller than a 34-tooth ring on one; forget the 30T ring. But yes, you could instead pair up 34-53 chainrings; shifting would be less than awesome, but pro teams sometimes use this combination for super steep stages, like the Monte Zoncolan in the Giro d’Italia.

You can just get the 34T, rather than the set. QBP (big wholesaler) sells individual Dura-Ace FC-9000 chainrings; it sells 34T, 36T, 38T, 39T, 42T, 50T, two different 52T — one for 36/52T, and one for 38/52T, 53T (for 39-53T, of course), 54T, and 55T.
―Lennard

Osymetric chainring adapters?

Dear Lennard,
I have a Ridley Noah RS and attempted to install 54/42 Osymetric rings. Even with the included adapter, I can’t get enough height or distance between the front Force derailleur and the chainring. I contacted Thomas Craven at Osymetric and he said he was developing an adjustable adapter but as of yet there is no immediate solution.

Do you have any experience with this problem or this setup?
—Craig

Dear Craig,
I know of no solution other than using a smaller chainring.
―Lennard

9-speed vs. 10-speed chains

Dear Lennard,
I am about to get a new road bike (Cannondale SuperSix EVO Ultegra Di2) with a 10-speed SRAM cassette and chain and compact cranks. I was under the impression the PC-991 SRAM chain was compatible with the 10-speed cassette. I still have a plethora of the PC-991 chains in their original packages. Since my LBS told me not to use them on the 10-speed, I need some expert assistance. BTW, I have always changed my chain yearly just, well, because.
—Michael

Subhead

Dear Michael,
The first “9” in “991” indicates that it’s a 9-speed chain. The 10-speed chain is the SRAM 1091 or 1071. I don’t know that you need “expert assistance,” you just need a 9-speed bike to use up all of those chains on, or you could put them up on eBay.
―Lennard

Clearing lawyer tabs

Dear Lennard,
I read your most recent article about lawyer tabs, where you mentioned Montague’s Clix. Following the link to Montague’s Clix, it said they were only for bikes originally supplied with Clix and could not be retrofitted.

How about the DT Swiss RWS (Ratchet Wheelmounting System) — does this product open far enough to clear the lawyer tabs?
—Jack

Dear Jack,
The DT Swiss RWS is not a quick-release skewer. It is simply a screw, and the lever arm ratchets so you can position it to line up however you want once it’s tight. So there is certainly no time savings relative to a normal quick-release skewer, which you would still have to unscrew to clear the Nader hooks, just as you would the RWS.
―Lennard

Stripping paint from carbon

Dear Lennard,
Regarding your recent Tech FAQ, here is a product for stripping paint from carbon: carbolift.com.
—Tom

Dear Tom,
That’s cool! Thanks!
―Lennard

The Zen/Zinn philosophy

Dear Lennard,
A cycling buddy, Joe from Ohio, sent me the link to your interview with The Outspoken Cyclist. You should put that link in your column. It was good fun to hear how you got into the bicycle business, and I’m sure there are others out there who what would love to listen. Your journey reminds me one of my favorite sayings, that life is what happens to you while you’re busy making other plans. And of course, you are the living example of the Zen/Zinn philosophy, that the path is more important than the goal.

One funny. When I applied to five colleges back in 1972, Colorado College was the only one I didn’t get in to. I went to Pomona College with the intention of being a chemistry major, but the chemistry professor suggested I start with physics. I can’t recall why. But once I was in the physics groove, I just never saw any reason to move across the street. For me, that led into the microwave business. It’s been a good career, but your path sounds like a lot more fun.
—Steve

P.S. Joe was on the show back on Feb 16. After retiring from HP as a computer engineer, he’s started a cycle touring company.

Dear Steve,
Well, in case you’re right and anybody is interested, now the link is in this column. Thanks.
―Lennard

In a recent Technical FAQ column, a reader asked a question that I have received a number of times regarding regular use of ProGold ProLink chain lubricant: Does using ProGold ProLink regularly reduce chain friction over time by smoothing the contact areas in the chain? To answer this, I turned to Friction Facts, one of our independent VeloLab partners in Boulder, Colorado.

As had happened with this reader, a ProGold employee once explained to me that ProLink is a “metal conditioner” with this effect. He told me that if you were to look at the surface of the metal in a chain with a high-powered microscope, it would look like the profile of the Pyrénées, rather than the smooth surface it looks to have without magnification. He said that, with frequent, regular use, ProLink would, over time, smooth those peaks down so the chain would run with lower friction. The ProGold website currently only says that ProLink “utilizes metal friction reducer technology.”

I believed this “metal conditioner” explanation and have passed it on a number of times, even in my maintenance books. I have used ProLink daily (or nearly that) for probably 10 years now. I still wear out chains, but I believed that it happened with less frequency than before, despite having been religious for at least 20 years about wiping and lubing my chain with some sort of chain lubricant after almost every ride. This past year I was riding more than I have in many years and went through an 11-speed Campagnolo chain much faster than I expected, and I went through two chains in one season on one of my cyclocross bikes last season.

When the VeloLab chain friction test we conducted at Friction Facts appeared in the March 2013 issue of Velo magazine, it showed that ProGold was ranked far from the top in friction reduction on new chains. I, too, thought that perhaps that test, being done on new chains, did not reflect the improvement over time that ProLink is purported to offer. It piqued my interest to test older chains that have been regularly lubricated with ProLink to see if there had been a friction reduction over time. I recently conducted exactly that test with Jason Smith at Friction Facts, and we could see no evidence of friction reduction over time with regular ProLink usage.

Procedure

I brought four used chains to Friction Facts: two SRAM 1091R chains (one from my travel road bike and one from one of my cyclocross bikes), a Wippermann Connex 10sX stainless steel chain that I keep as a spare in my travel bike case, and a KMC X10SL chain from my other cyclocross bike. All of them have been regularly lubed with ProLink over time, and all were still within wear specs (they run on new cogs without skipping under load). None of them had ever been cleaned; I just had done with them what the ProGold employee had suggested, which is simply to wipe them with a rag and lube them frequently with ProLink, starting when new.

We had not tested these particular chains when new, so this was not a before/after test and should be viewed as indicative, but not definitive, of testing the same chain over time. We ran the chains on Friction Facts’ full-tension chain friction test machine; visit Friction Facts’ website for a description of the machine and how it works.

We had results on these same types of chains, in new condition, from the VeloLab friction test and other tests Friction Facts has performed on chains in the past. The frictional drag results in the VeloLab test on the new, clean chains lubricated with ProLink, of which one chain was a SRAM PC1091R, were always below eight watts, and the average was 7.23w. However, our results for the used chains lubricated over time with ProLink were always above eight watts.

This indicates that the chains do not run faster after long wear with regular ProLink application than they do when new and lubricated with ProLink. We did not test cleaning the old chains and then putting ProLink on them, as I was interested in the results for chains maintained over time just as the ProGold employee had told me to do, namely: wipe them with a rag and lube them with ProLink after every few rides, and don’t clean them with solvent.

When we added ProLink to one chain, the KMC, while turning without load on the test fixture, the drag dropped by 0.42w, from 8.58w to 8.16w. When we subsequently lubricated that same chain with the second-best-performing lube in the VeloLab test, the Rock and Roll Absolute Dry, that same chain dropped by almost two more watts, to 6.33w. (In both cases, we just dripped the lube on; we did not do any chain cleaning.) When we applied WD-40 Bike Dry Chain Lubricant on the old Wippermann chain, it did not change the drag at all from its performance with ProLink that was still on there from years ago, as I have been carrying that chain around for a while as a spare.

Results

The graph at the top of the story, Image 3 in the gallery, shows the entire test.

The first peak on the graph is a new, Friction Facts “UltraFast” chain (in this case a 10-speed Dura-Ace), on which Friction Facts performs the following steps:

The UltraFast chain optimization summary: A new chain is run-in under load on the lab equipment. This run-in process polishes the link’s sliding surfaces and removes roughness and manufacturing imperfections. The chains are then ultrasonically cleaned to fully remove the factory lube and friction-producing contaminants introduced during the manufacturing process and run-in period. The chain is then ultrasonically infused at high temperature with a Wax/PTFE/MoS2 blend. The chain is removed from the wax bath, cooled, and run at load again to allow the now-hardened wax blend to further bond under pressure to the metal surfaces and set up the thin lubricating layer between the pins, plate shoulders, and rollers. A second PTFE layer is applied, and finally the chain is placed on the lab equipment for a final run-in and measurement of the friction level. The equipment screen capture is included with the chain. This two-step lubrication process allows the sliding surfaces of an UltraFast Chain to have three distinct lubricating layers working together as a system.

The second peak is a new chain (in this case a SRAM PC1091R), cleaned and lubricated with the worst-performing lubricant in the VeloLab test, White Lightning Epic Ride.

The third peak is my old, ProLinked-over-time SRAM PC1091R chain from one of my cyclocross bikes (used the second half of the 2012-13 cyclocross season).

The fourth peak is my old, ProLinked-over-time KMC X10SL chain from my other cyclocross bike (used the entire 2012-13 cyclocross season).

The fifth peak is to be ignored; it is just the machine running under no load during application of ProLink on that same KMC X10SL chain.

The sixth peak is that same KMC X10SL chain after fresh application of ProLink.

The seventh peak is that same KMC X10SL chain after fresh application of Rock and Roll Absolute Dry lube.

The eighth peak is my old, ProLinked-over-time SRAM PC1091R chain from my travel road bike.

The ninth peak is my old, ProLinked-over-time Wippermann ConneX stainless chain from my travel road bike, which has not been used for a while and is kept in a plastic bag in my travel case as a spare.

The 10th peak is that same Wippermann ConneX chain after application of the new WD-40 Bike Dry Chain Lubricant. This lube was from a sample container handed out at a bike event; it was not tested in the VeloLab chain-friction test, because it was not yet available at the time that test was conducted.

Note that we did not run any new chains with ProLink in this particular test; the comparison I make to them above is based on the VeloLab chain test results. Friction Facts has demonstrated consistency of its results on its equipment over time, so we are confident that we would have gotten the same result as the VeloLab test, had we run a new, cleaned-and-ProLinked chain during this particular test.

Summary

We could find no evidence that frequently wiping down a chain and lubricating it with ProLink will reduce its friction over time in comparison to a new chain of the same type with the factory lubricant cleaned off, followed by lubrication with ProLink.

Determined not to have it be pigeonholed as a bike for older and slower riders, Cannondale engineers and industrial designers built the new 2014 Synapse with “Synapse Endurance Race Geometry” (“S.E.R.G.”) and have, from the outset, made racing part of its pedigree.

Its first use in a race was the Strade Bianche in the Chianti region of Tuscany, and Cannondale rider Moreno Moser won the race on it. Peter Sagan subsequently won Ghent-Wevelgem and Brabantse Pijl (Brabant Arrow) on a Synapse Hi-Mod, along with second places in Ronde van Vlaanderen (Tour of Flanders) and E3 Harelbeke. Sagan also finished second in Strade Bianche, but he was riding a Super Six EVO in that race.

“I was at first reluctant [about using the Synapse] until I tried it [and liked it] in Belgium,” Sagan said.

Like the Super Six EVO and some high-end Cannondale mountain bike models, the Synapse Hi-Mod is built with BallisTec carbon fibers designed for military armoring covered by strategically placed and entirely interconnected strands of high- and ultra-high-modulus carbon fibers over the entire frame to give it stiffness in desired areas. The hot-cure resin and carbon layup are selected to absorb bump energy through “inter-laminar shear stress dissipation” (i.e., energy is absorbed in the shearing of the layers relative to each other). The twisted “helix” seatstays maximize the length of the fibers relative to the length of the stay to increase vibration dampening.

Full gallery of the Cannondale Synapse Hi-Mod >>

The flattened S.A.V.E. (Synapse Active Vibration Technology) shaping of the stays and fork legs, introduced in 2006 with the first Synapse, has been refined and is now called S.A.V.E. Plus, intended to provide more movement at the axles when the rider is either seated or standing. The helixed seatstays are designed to compress and twist a bit like a spring to let the dropouts move vertically more.

The fork is designed to also flex a bit inside the head tube as well as in the fork legs. This has been accomplished with a smaller tapered head tube, which goes from 1.25-inch (rather than 1.5-inch) tapering to 1.125-inch.

The 1-inch-diameter (25.4mm) seatpost is slim in order to provide more bump compliance, especially when a lot of seatpost is exposed. The collarless seat clamp shortens the top of the seat tube to increase the exposed seatpost length by 65mm. A vertical bolt tightens a wedge system against the front of the seatpost, and a bump in the crotch of the top tube/seat tube joint houses the wedge.

Finally, the most distinctive part of the frame is the seat tube; it has a cutout where it meets the bottom bracket. To allow it to bow, the seat tube is thin fore-aft near its base; this is carried over from the 2006 Synapse. Additionally, however, the “Power Pyramid” at the base of the seat tube is an asymmetrical offset split in the tube. Material has been removed from the long walls of the oval cross section and is instead concentrated into two more round pillars that meet the extra-wide (73mm) “BB30A” bottom bracket shell at its ends. By increasing the stance width, it becomes stiffer at opposing the torque on the bottom bracket shell from pedal forces with less weight, while maintaining the bowing flex of the seat tube over bumps and in response to rider weight on it.

The bike comes in 11 distinct sizes — six for men, five for women, including a 56cm women’s size — with three different fork rakes, depending on the frame size.

The Cannondale pro team requested the bike for the spring classics, “and of course we said yes, even though it was not ideal in terms of a marketing launch of the product,” U.S. road marketing manager Murray Washburn said. Willing to bear the costs of making new molds for Sagan (as he is a sponsor’s dream), Cannondale built his Synapse Hi-Mods in custom sizing; the rest of the team rides on stock frames.

The Synapse Hi-Mod frame is about half a pound heavier than the Super Six EVO (950g vs. 720g), but it is considerably lighter than most other entries in the endurance road bike category. The 61cm, SRAM Red 22-equipped Synapse Hi-Mod I’m riding in Tuscany weighs in at 6.93kg with pedals — just barely UCI-legal!

Ted King also likes his Synapse Hi-Mod, and says he wanted one from the first time he saw a plastic model of it. “You can ‘take that left turn,’” he said, meaning that the bike tempts him to discover where an unknown dirt or otherwise bumpy road goes. He has the riding position he wants on it despite the head tube being 3cm taller than his EVO and the top tube about a centimeter shorter. Instead of a 90-degree stem with a spacer under it like he has on his EVO, he has a longer, down-angled stem with no spacer. “It looks cool,” he said, “because now I have a slammed stem.”

Sagan said the bike is comfortable on rough roads and it handles well on the bumps. He still likes the way it sprints, like when he is sprinting away from the group and holding on for a solo win.

“It was perfect when I won Ghent alone,” Sagan said.

I rode the bike on a 60-kilometer group ride on the course of l’Eroica today, and I would agree with him. It sprints great, yet it is quite comfortable given the conditions on the rough, potholed and sometimes washboard “strade bianche” (white roads, dirt roads) here in the hilly region of Chianti.

Pulling cranks

Dear Lennard,
Thank you for the helpful article on Campagnolo Power Torque chainset dismantling.

Do you think that for just removing the cranks (aluminum or carbon fiber), an ordinary gear puller, such as one of the pullers shown here, would work OK?
—Nick

Dear Nick,
Yes, I think it would work fine. You obviously will have to fashion a plug to put in the end of the spindle for the push rod to push against after you’ve removed the crank bolt and washer. You may want to pad the tool’s tips with cardboard to avoid marring the back of the crankarm.
―Lennard

MTB crankset combos

Dear Lennard,
SRAM seems to attribute the best possible front mountain bike shifting to the 3:2 ratio of their 2/10 cranksets, but it is only true of the 42/28 and 39/26. The other two offerings, 38/24 and 36/22, stray from this “golden ratio.” Shouldn’t a 36/24 offer the same advantage (perfectly aligned teeth) they are touting for the first two? I am new to mountain biking but am always looking for better shifting.
—Mike

Dear Mike,
Here’s the answer from Chris Hilton, SRAM’s mountain bike components product manager:

It’s true that these combinations don’t follow our complete X-glide shifting formula. Ultimately, we learned a lot about shifting performance when developing the X-glide 26-39 and 28-42. The ratio of the rings is one aspect of the system that encourages quality shifting, but ring design, rivet location and design, chain features, and FD cage design all play an important role.

We ultimately used market and customer feedback to determine the combinations of gears that were desired, chief among these was the low double 22-36 and 24-38. Based on our previous experiences, we knew that we could provide the superb shifting that SRAM 2×10 has become known for, AND deliver the desired gear ranges.

The growing popularity of the 2×10 system pioneered by SRAM continues to evolve, covering our entire drive train range from XX to X5, and even includes a new VIA GT 2×10 trekking group. Given its widespread acceptance, I’m sure that it will continue to evolve and provide the best possible drive train options for a wide variety of customers.
—Chris Hilton

Lawyer tabs

Dear Lennard,
I’m watching 3 Days of De Panne and the commentators mentioned the lawyer tab rule change again, as is often the case. Isn’t it possible to just make quick release levers with a big enough of a cam effect that they will clear the lawyer tabs? One would think that this wouldn’t be too difficult to do in an era with such technological advances as electronic shifting. The rule change seems really stupid to me, but everyone seems resigned to just keep using the same old QR levers.
—Charlie

Dear Charlie,
Yes, long-throw quick release levers do exist. You find them on many roof racks, of course, or getting bikes with lawyer tabs up on the roof would be far harder. Montague’s Clix is a skewer that clears the tabs. Neuvation also used to offer long-throw levers for use on the bike, but I can no longer find them on neuvationcycling.com.
―Lennard

Dear Lennard,
I’m a lawyer and I don’t file my lawyer tabs. Not because of liability concerns, though. The reason is the crash I witnessed during a Roubaix-style road bike race when the rider three bikes ahead of me heard a clanking noise and upon lifting up his front wheel to check it, pulled the wheel right out of the fork, which yes, had its lawyer tabs filed. He no longer has any of his original front teeth.
—Tre

Dear Tre,
Youch! I have seen people with loose skewers lift their front end after stopping, only to have their wheel fall out. One of them turned quite pale, having just completed the descent into Silverton, Colorado in the Iron Horse Bicycle Classic with his wheel loose enough to fall out.

To lift up on the front end while moving when you hear a suspicious rattle is an ill-advised strategy, whether it is due to a loose skewer or something else. It’s a good idea always to stop and then check it out.
―Lennard

Removing paint from a carbon frame

Dear Lennard,
I am considering purchasing a carbon frame on sale with a hideous paint scheme. Is there a safe way to remove the paint and either leave it as bare carbon or re-shoot to spec? And if left as bare carbon, is that a good or bad thing? I want to avoid a spray over as not to add more weight, whatever that may be.
—Paul

Dear Paul,
Paint remover would not only dissolve the paint but also the resin that holds the carbon matrix together. The only way to safely remove the paint would be to sand it off by hand and stop before you sand off any carbon. This is not practical if your time is worth anything.
―Lennard

Pedal stroke technique

Dear Lennard,
I’m just wondering what you think of this quote from your recent bike fit article:

Just use the hamstrings to unweight the pedals and never pull back on the stroke or simulate scraping mud off the shoe …”

This seems to be the story of the whole article. Haven’t we always been told to scrape mud (or something else) off the shoe when pedaling? Ever since I started riding and racing, that has always been the mantra of pedaling. Is Bailey’s technique a new way to think about pedaling or did I just miss something? Would like to hear more about this old vs. new way to think about the up stroke.
—Jack

Dear Jack,
I had Kevin Bailey, the owner of 3D Bikefit, answer your question; this is what he said:

“Scraping mud off the shoes — does it help or hurt the stroke? The key to a clean efficient pedal stroke is Tangential energy. When a rider can rotate on the saddle at the Pelvis they’re able to engage the Gluteus and upper thigh muscles instead of the much smaller lower quad muscles. When a rider tries to “scrape mud” it causes a jerky pedaling action that forces the rider to push down at the top of the stroke and pull at the bottom. This can lead to lunging and dropping of the heel, which effectively varies the saddle height on the bike and can lead to injury. An effective pedal stroke using Tangential energy comes from a good fitting and is a result of proper saddle height, fore-aft position, Pelvic rotation, ankle position and learning to engage the Gluteus and hamstring muscles
—Kevin

IT band stretches

Dear Lennard,
In your article titled “Bay Area fitter utilizes exclusive 3D technology for in-depth bike fits,” you mention IT band stretches that Kevin recommends to his clients. Do you have instructions? I am an avid cyclist and former [Ironman] athlete with chronic ITB syndrome. The ITBS has kept me from running, and is starting to impact my riding.

I am looking for any fit/stretching advice I can find that will help me be pain free on my long rides.
—Daniel

Dear Daniel,
Put one foot up on a step and lock both knees. Lean forward with your back flat and turn toward the side of the leg that is raised. Keep leaning forward further while twisting more to that side; you will feel the pull on your IT band on the leg that is up on the step. I’ve been doing this at least daily since November, and I think it’s reduced the number of occurrences of IT band pain, something that has plagued me a number of times over the past 24 years.

I’ve tried other IT band stretches over the years, and I found them to be either more hassle than I was willing to do regularly, so I didn’t keep them in my daily routine, or I felt them to be ineffective. Rolling out the IT bands on a foam roller has been the most effective thing I’ve found other than this stretch, but I travel a lot and don’t bring a foam roller, and even remembering to do it at home is surprisingly rare. The only time my IT bands have flared up since doing this stretch regularly was during (and the day after) the Birkebeinerrennet 54K classic-technique cross-country ski race in Norway on March 16.
―Lennard

Puncture-proof tubular tires

Dear Lennard,
Following up on your article on the new Michelin tires, where you noted that the new tubular was ridden in 2012 by Ag2r at Paris-Roubaix and Le Tour, how common are tubulars with puncture-resistant belts on pro team rigs? I could see it being a good idea at Paris-Roubaix or Strade Bianche, but do they tend to equip them for other races as well?
—Clark

Dear Clark,
Essentially all racing tubulars have a puncture-protection belt under the tread. The only exception is superlight time trial and track tubulars. I ran your question by a number of manufacturers and have paraphrased their answers below.

Vittoria: All of Vittoria’s cotton casing tubulars have a PRB layer under their tread. The technical specification of the PRB can change, based on the model. Regarding the question from Clark, some riders use PitStop (prevention against punctures), but this is an additional measure.

Vredestein: Fortezza Pro TriComp has a protection belt; company claims the tire “is famous for being extremely puncture resistant.”

Challenge: All Challenge tubulars have protection under tread, and now for the Almanzo Gravel, have adopted double protection (see photo). The second protection belt is placed inside the tire casing and goes in direct contact with the tube; this is Challenge’s new double protection system.

Tufo: Protective belts in all road tubulars, except the training PRO series.

Clement: Protective belts in all road tubulars.

Schwalbe: Current high-end tubular range includes 22mm and 25mm Ultremo HT, which come with a RaceGuard protection strip. However, a 22mm Ultremo TT is similar to the Ultremo HT, but comes without the RaceGuard breaker.

FMB: Protective belts in all road tubulars.

As you can see, puncture-protection belts are standard in road racing tubulars.
―Lennard

Wheels sizes and gear ratios

Dear Lennard,
I am having a hard time wrapping my head around rotational inertia of wheels and gear ratios. The main sources I’ve found online, here and here, suggest that wheels with greater diameter are no faster than smaller wheels. In a perfect world, if two completely identical riders rode two bikes, one with 650C wheels and the other with 700C wheels, in the same gear, say 110 gear inches, with the same cadence, each rides for exactly 30 minutes, would they travel the same distance? I would assume no … but that does lead to another question.

Same riders and same bikes, except the bike with the 650C wheels can ride in a higher gear. Both riders run their max gears; the 650C has 122 gear inches and the 700C has 116 gear inches. Does the lower rotational mass of the 650C wheels have any bearing on energy used?
—Dave

Dear Dave,
Your assumption is false. By definition, the two riders on 110-inch gears travel the same distance. That’s because the gear inches value includes the wheel diameter.

Here’s the formula: Gear size = (number of chainring teeth) x (tire diameter) ÷ (number of cog teeth)

If you want the gear in inches, put in the tire diameter in inches. To find out how far you get with each pedal stroke (gear rollout), multiply the gear by π (3.14159).

Because of this fact, your second question makes no sense. It’s interesting that the larger gear ratio you quote is on the smaller wheel; apparently the chainrings on that bike must be huge. If you’re trying to get at an increase in efficiency (or not) with smaller wheels, you won’t get there from looking at gear inches, particularly if you don’t take into account that the gear inches includes the tire diameter.

There is no universal truth you’re going to find in an equation that says that 650C wheels are faster than 700C wheels or vice versa. Some conditions favor one size and some favor the other. In a nutshell, assuming similar tire and wheel construction, 650C wheels will be faster when it comes to sheer weight against gravity (i.e., climbing), and both weight and rotational inertia when accelerating (racing criteriums). Rolling resistance is higher with decreasing wheel size, so rolling at steady state, especially on rougher surfaces, will favor 700C. I am pretty sure that most wind tunnel testing with average size bikes indicates that the entire bike with wheels is not aerodynamically better with 650C (and can be worse), since the head tube is longer.
―Lennard

Less spoke holes on the hub than the rim

Dear Lennard,
In a recent Technical FAQ column, Davo asked about using a 32-hole hub with a 24-spoke rim. Can you do the reverse (24-hole hub with a 32-spoke rim)? If so, what do you do with the unused rim holes to prevent water/dirt incursion?
—Frank

Dear Frank,
No. That’s a great way to make a flimsy wheel. I’ve also tried that. Only once, though!
―Lennard

Feedback on blowing Hutchinson Fusion Kevlar-bead tires off of rims

Dear Lennard,
On the bottom question in this article, the reader is having trouble with tires blowing out. Something that I have seen here in Boise, Idaho, is that people seem to think that since the Mavic Ksyrium rim has no spoke holes, that it is a tubeless rim. Another thing is that people have not been noting the difference between Kevlar- and Carbon-beaded Hutchinson tires of the same model. Either of these mistakes can lead to catastrophic failure, and I have seen this mistake made several times by people that do not know that they are making said error. Ksyriums are not tubeless and Kevlar-beaded Hutchinson road tires are not tubeless either. With the details given in the post, I do not know if you could have ruled this out, but in my experience, people keep making this mistake.
—Colin

Dear Lennard,
I run Campy Proton clincher rims, and they are slighter larger than Mavic rims. I broke several tire irons and pinched many a tube while I was running Michelin tires. A friend recommended Hutchinson tires, saying that they were a little bigger, and I have been using them for several years now, without any installation problems. Campy USA said that with a slightly larger rim (theirs), a flat tire is much less likely to come off than it would be on a smaller rim. My guess is that if you can’t fit Michelins on Proton rims and you can fit Hutchinsons on them, then you probably shouldn’t run Hutchinsons on Mavics, because Michelins fit fine, and Hutchinsons would be a looser fit.
—Louis

Research shortcomings and kerosene for chain friction

Dear Lennard,
Reading your last column in VeloNews, I was reminded of a neat refutation of the idea that larger sprockets give lower friction. It was published in issue 51 of Human Power (2001, p. 14-15), following an original article by Spicer published in the previous issue of that journal.

The author’s insight was that, although larger sprockets indeed have less friction for a given loading, in practical use the higher efficiency from higher chain loading occurring with smaller sprockets more than makes up for this. They prove it using Spicer’s data, too!
—Francisco

Dear Francisco,
This smelled a bit fishy to me, so I had Jason Smith, proprietor of Friction Facts, one of our independent partners at VeloLab, answer your question. He thinks about this stuff night and day, and this is what he said:

What is interesting is how these conclusions are made. This paper is an example of a conclusion, which uses incorrect assumptions, based on data from another paper, which uses incorrect assumptions. It’s a similar effect as the telephone game.

As I’ve mentioned before, Spicer et al’s paper has many correct conclusions. However, with regard to tension versus efficiency, they made a major incorrect assumption in the paper by not segregating the frictional contribution of the chain as it snakes through the pulleys. From Spicer et al’s paper, “Since the chain tension is large only on one side of the drive, this loss only has significant contributions at two points — at engagement of the chain on the front chain ring and departure on the rear sprocket.”

They did not consider the effects of lower span friction in their formulas and calculations, and assumed all friction was due to the top span. We now know that approximately two-to-three watts of friction is created by the lower pulleys and the lower three chain spans due to the applied two-ish pounds of tension from the derailleur arm. We know that it does not vary due to rider load or corresponding chain tension. Spicer et al assumed the total friction he was measuring was due to only the top span, when actually, it is a joint contribution from the top span and the fixed-friction lower spans.

Because the lower span friction does not vary with tension, their incorrect assumption skewed the linearity of the friction versus top tension and efficiency versus top tension graphs, and therefore their results with regard to efficiency versus tension. Additionally, when they plot out their tension versus efficiency results, the efficiency exceeds 100 percent in all three sprocket test cases at higher rider output. This, if correct, would be the discovery of perpetual motion. According to their data, any Tour rider with high enough power output would actually be propelled by the drivetrain rather than slowed by it.

The FF test “Chain Efficiency vs. Load” (http://www.friction-facts.com/free-chain-efficiency-load) has two graphs. The first is the total drivetrain losses vs. friction. Note the zero offset. It is a standard Y=MX+B equation. This fixed offset is due to the pulley and lower span friction, and the linear increase in friction with load is due to the top span. The second graph plots this as an efficiency percent versus load. Now, the efficiency versus load graph is non-linear, and correctly shows a trend of increasing efficiency with increasing load. However, this non-linear increase is not due solely to the friction of the top span. It is due to the combination of the fixed friction in the lower pulley spans and linear increasing top span.

In the second paper, the authors take Spicer et al’s data regarding tension and efficiency (which in my opinion is not good data), and make additional incorrect assumptions. They do not include the friction losses in the front ring in their calculations. The authors state, “We assume that most of the chain loss is associated with the rear sprocket,” and they subsequently create formulas and perform calculations based on this incorrect assumption by leaving out the friction effects of the front ring. This is important, because the meat of their theory is based on the effects of 11- versus 15- versus 21-tooth sprockets. As they keep speed of the rear sprocket constant and power constant, they do not account for the tension needing to be lower on the front ring with the use of a larger rear sprocket, which would decrease overall friction losses. The contributing effects of the front ring are essential, and, if included in the calculations, would contradict the author’s conclusion, in my opinion.
—Jason

Dear Lennard,
Word etymology is fascinating. The root of kerosene comes from the Greek “keros” meaning wax. In a broad sense in chemical terms, paraffin is an oily or waxy mixture of hydrocarbons, hence its use as a word substitute for kerosene in the U.K.

Actually, an easy way to wax your chain (without having to heat-melt paraffin into a liquid) is to dissolve flakes of wax in kerosene (as much as will dissolve). Then you can use a brush to dab it on to your chain. The excess is wiped off, the kerosene eventually evaporates and you’re left with a tidy chain lubricated with wax.
—Steve

In a departure from its long tradition of serviceability and tool-making, when Campagnolo introduced the Power Torque (PT) integrated-spindle crank to provide a lower-cost alternative to its Ultra-Torque (UT) cranks, it provided neither a tool nor a methodology to remove the crankset from the bike or to remove the driveside bearing.

Installation is as simple as can be, with only a 14mm hex key, if you have one that big. But while most integrated-spindle cranks, including the Campagnolo Ultra-Torque and Fulcrum Racing-Torq models, can be removed with only a hex key, the Power Torque crank requires a puller. Bike shops needing to service them were doing things like modifying automotive gear pullers to get the left arm off. Bike tool companies like Park and Cyclus soon stepped into the breach and came up with solutions. Here is how to use them.

Instructions for removing the left Power Torque crankarm with the Park CBP-3 UT/PT puller and CBP-5 Power Torque adapter tools (you’ll need both tool sets):

1. Unscrew the crank bolt with a 14mm hex key. The arm will not come off.

2. Remove the washer. If the washer did not come off with the crank bolt, get it out of the crankarm hole. If you don’t, you won’t be able to pull the crank off and may wreck your tool and your crank trying.

3. Pad the crank. If it’s a carbon Power Torque crank, install one of the cardboard curved pads from the CBP-5 tool set under the head of the crank. If it’s an aluminum crank, slip the molded plastic cupped pad from the CBP-5 tool set under the head of the crank. (The head of the aluminum Power Torque crank has a curved edge that terminates in a ridge around the end, and the feet of the CBP-3 bearing puller that you will be employing to pull the crank off cannot grab it well without marring it, hence the plastic molded pad to protect the crank finish. The carbon Power Torque crank, by contrast, has a flat back face that mates well with the bearing puller’s fingertips, so a cardboard pad is sufficient to protect it.)

4. Insert the extension plug. The plug will push on the end of the spindle (as long as you removed the washer that was under the crank bolt) when the bearing puller’s push rod pushes on it.

5. Install the CBP-3 bearing puller. Hook the puller’s fingers under the pad surrounding the head of the crank (there are little recesses for the fingertips under the edges of the molded plastic pad), and tighten the two side knobs to remove play from the puller’s fingers so they can’t slip off.

6. Pull the crank off. Tighten the push rod until the crankarm comes off.

You can also use the Cyclus 720310 puller to remove carbon Power Torque cranks or the Cyclus 720249 puller to remove aluminum Power Torque cranks.

7. Yank out the drive arm. Pull the spindle out by pulling on the drive crank. If it’s stubborn, tap the end of the spindle with a soft hammer. Catch the wavy washer.

Bearing removal

The Park CPB-3 puller will get the bearing off the spindle of Campagnolo Ultra-Torque and Power Torque and Fulcrum Racing-Torq cranks, but for Power Torque cranks you’ll also need the CPB-5 tool set. A puller like this Park combination or the long Cyclus 720248 puller for drive-side Power Torque bearing removal is required; you do not want to pry with a screwdriver against a carbon crank to get a bearing off!

1. Remove the crankarms as above.

2. Remove the circlip holding the bearing onto the spindle. With a screwdriver, push one end of the circlip out of its groove, and then work around with the screwdriver to pop the entire clip out. This applies to both arms of Campagnolo Ultra-Torque and Fulcrum Racing-Torq cranks and only to the drive arm of Campagnolo Power Torque cranks.

3. Install the bearing puller. On Ultra-Torque and Racing-Torq, hook the fingers of the CBP-3 puller under the edge of the bearing and tighten the two side knobs to remove play from the puller’s fingers so they can’t slip off. On Power Torque, first slip the CBP-5 steel extension basket under the bearing to extend the reach of the CBP-3 puller sufficiently to reach the Power Torque’s full-length spindle. The puller-extension basket will just slip under with standard-spider (135mm BCD) PT cranks; with compact (110mm BCD) PT cranks (for down to 34-tooth chainrings), you’ll have to remove the inner chainring to slip the tool under the bearing. Hook the CBP-3’s fingers into the slots at the top edges of the basket and tighten the two side knobs to remove play from the puller’s fingers so they can’t slip off.

4. Tighten the push bolt of the CBP-3 puller clockwise until the bearing pops off. On Campagnolo Power Torque cranks, the left bearing is pressed into the cup, as on bottom brackets, for 24mm-integrated-spindle cranks made by most other brands. It can be pulled out with the same special tool required for Shimano, FSA, SRAM, etc. bearing removal, or you can replace the cup and bearing.

Bearing Installation

1. Replace the bearing seal on the spindle.

2. Slide the new bearing onto the spindle as far as you can by hand.

3. Press the bearing into place. Use the CBP-3 (UT and Fulcrum only) or CBP-5 bearing setter and a hammer; on Power Torque, you’ll need the longer CBP-5 setter. The Cyclus 720263 bearing press for driveside Power Torque bearing as well as Ultra-Torque bearings tightens the bearing onto either UT or PT cranks with a screw, rather than with a hammer.

4. Slide on the snapring, and push it into its groove.

5. Reinstall the crankarms.

I have received a lot of questions for my FAQ column on how to remove PT cranks. This should answer that, although the tools required, whether from Park or Cyclus, are large and pricey. It’s a big ask for consumers to have these and be able to remove their own cranks.

Ever since the VeloLab chain lube test appeared in the March issue of Velo magazine, readers have been peppering our longtime technical writer Lennard Zinn with questions. Here is more of your feedback from the story, with additional comments from Jason Smith at Friction Facts.

Wax has its benefits

Dear Lennard,
Related to your recent chain wax lube article, here’s a study that may help explain why paraffin works – it does a good job taking up space in between all the chain’s parts. One surprising finding – the lube doesn’t have much effect on a chain’s efficiency. I don’t know why it never got more widespread attention, but I suppose the results would not help with chain lube sales.
Ed

Dear Ed,
Those indeed seem to be surprising results. The cog size increasing chain efficiency is legit, though. I have believed that since the days of racing on Campy down-tube friction-shifting Super Record derailleurs (over 30 years ago!), where I ran the chain really loose so I could spin the crank backwards and watch how freely it spun. I could see the difference based on cog size and thought I could feel how much more efficient it was in a larger chainring and larger cog than riding similar gear inches using a smaller cog and chainring.

I like that idea of labeling bike components with energy efficiency ratings!

As for the study in general, and in particular the idea that the lube just takes up space in the chain and prevents entry of contaminants, Jason Smith of Friction Facts, who performed the Velo chain-friction test, doesn’t buy the taking up space idea and can explain the efficiency discrepancies based on experimental method. Here is his explanation:

“Yep, this is the “Spicer” paper which is commonly referenced when looking at drivetrain efficiency. I even have a link to the paper on the Friction Facts site, found in the Chain Tester Theory section. Here’s the complete paper.

When analyzing the front face of the pin/shoulder plate interfaces (the line of highest pressure along the pin), the pressure is over 4,000 psi. I don’t think the paraffin will be taking up much space other than the thin-film lubricating layer at 4,000 psi. Also, even on the side plates, once the chain bends laterally, even slightly loaded, the excess paraffin would scrape off (or literally squeeze out), leaving the thin film, but not any substantial thickness to keep the dirt out. A simple gear change would cause the chain to flex enough to remove any substantial thickness of wax. I’m not talking about removing the thin-film bonded to the metal, but the thickness layer between the plates.
Jason

How’s that for a thorough explanation?
― Lennard

Wax or kerosene?

Dear Lennard,
It’s long been my contention that the lubing of chains with paraffin wax might have been borne out of a confusion of terms. Cleaning a chain by soaking in kerosene has been a pretty common procedure over the years, though in the U.K. the translation would be to soak it in “paraffin.” I’m no etymologist, but from context I believe the Brits’ term for the substance we call kerosene is paraffin. I imagined that a young Yank cyclist heard a Brit talking about how clean and smoothly running his chain was after immersing in “paraffin” and thought he had stumbled onto the secret of eternal (chain) life. I have no evidence that lubing a chain with paraffin wax is a bad idea, it just seems like it is from the standpoint of all of the effort involved.

By the way, did the lube tester also test no lube at all? Perhaps a freshly cleaned, un-lubed chain has even less resistance, or maybe a constant drip of water from a water bottle to keep the chain lubed with very low viscosity.
Mike

Dear Mike,
Well, that’s an interesting etymological theory! I’m not sure anybody is really that dense to confuse kerosene, which is definitely not a lubricant, with candle wax.

As for your question, Jason from Friction Facts actually has since tested without lube, and here’s what he has to say about it:

“Two weeks ago, I actually analyzed six chains after water and after lacquer thinner (completely dry, but a clean dry albeit). This is a continuation of the “Dirty Chain” test (attached).

Please note: the water does not simulate rain. Riding in rain would kick up some road dirt and grime. I speculate that after riding in the rain, and then if the chain were allowed to dry, we’d see 10-12ish watts of friction. I feel a thin lube film would still be present after rain, but the road grime would increase the friction.
Jason

So, it appears that a dry, unlubed chain is very resistive to your efforts to propel the bike, just as it seems when you let your chain get that way in actual use.
― Lennard

Wax with … graphite?

Dear Lennard,
I started using wax mixed with graphite many years ago, after getting fed up with grease on my club jerseys. Learned about it from a fellow who raced tandems and he was fed up with replacing expensive drive trains.

My Litespeed still has the original cassette on it from 2005, with upwards of 25,000kms! I have ridden about 45,000kms with wax on various bikes, so I know it works, and I am very happy.

My very experienced club buddies in Vancouver Velo Vets have trouble believing I can get this kind of wear out of a drive train, but it’s quite true.

Here’s what I do:
Rainy Days
I ride a winter road bike and mountain bike in the rain with regular oil on the drivetrain. I happen to use sewing machine oil bought in quart containers.

Dry Days
I use my good bikes, which are a Litespeed, carbon Devinci and a track bike with a wax and graphite mix on the chain.

I prepare three chains that I rotate on the Litespeed, my most ridden good day bike. Each chain lasts about 500km before it gets a slight squeak. This squeak tells me it’s time to rotate the chain. I buy cheap paraffin wax candles at the dollar store, graphite powder at the hardware store and mix up three or four candles with the small package of graphite in a coffee can. Heat it up in a large pot of water. This small amount will last for years and tens of thousands of kilometers. I’m still on my original batch!

Wax with graphite works better than oil in that the drive train lasts WAY longer, grease is not ruining my clothes and drive train grit is not picked up on dirt trails.

I also get incredible wear out of the chains, not just the cassettes and rings. I change the chains after almost 20,000km only because they get side-to-side wear, not stretch wear. I have never had a chain or connecting link break.

After about 500km I switch chains, only when it squeaks. Now and then I heat up the batch of wax and relube the three chains.
Casey

Track wax

Dear Lennard,
In terms of the chain waxing, I think what a lot of readers are missing is this is a point of the spear activity.

Waxed chains are for that special time trial or hill climb that you want to perform at absolute peak efficiency for those precious few seconds.

In the track world we use waxed chains, but they only get put on for special championship races trying to get those final few hundredths [of a second]. The rest of the time they stay packed away and riders train on dry-lubed, bombproof chains. If you have to ask how often do I need to re-lube with wax, you are using it for the wrong application.
Mark

Misleading results?

Dear Lennard,
While I trust the friction test results, I think referring to a lube that contains as much PTFE and Molybdenum Disulfide simply as “paraffin” is misleading. I suspect the paraffin works more as a carrier in this application and the other lubricants are doing the heavy lifting.

I too have anecdotal evidence of longer chain life with ProLink, though for exceptionally long or wet rides and races I use something heavier duty. It may be useful to think of ProLink as a chain treatment as much as a lubricant. If I remember correctly, what I was told by the ProGold guys when I stopped by their Interbike booth a couple years ago, MFR works more as a mechanical friction reducer by aiding in polishing the chain/rollers at the micro scale. This smoother surface would reduce wear as we have both experienced. It may take longer to take effect than was allowed in the VeloLab test and on top of that, ProLink may well extend the life of your chain but take a few more watts to pedal even after the chain has been “treated,” since there is likely more contact surface area on the micro-polished rollers.
Rob

Dear Bill and Rob,
The paraffin used in the Velo test was actually pure paraffin (Gulf Wax brand), without any PTFE (Teflon) or MoS2 (molybdenum disulfide). The Friction Facts wax blend (with PTFE and MoS2) was not tested in the Velo comparison; only pure paraffin was tested.

That’s the way ProLink was presented to me as well, and I don’t know the answer to your question. I was told by ProGold that the chain got smoother over time.

I plan on testing (at Friction Facts) some chains I’ve been riding on for a long time with ProLink and see what happens.
― Lennard

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

BOULDER, Colorado (VN) — Getting your bike(s) to far-flung races can be a major hassle, and dealing with mechanical issues when you’re there can multiply it. Pro Bike Express offers bike transport to races all across the country, and it has stepped up its service to include taking care of riders’ mechanical and personal needs like a professional team would.

Pro Bike Express proprietor Wesley Smith loves to drive as well as to wash bikes, and he has endless patience, a cheery willingness to deal with any weather conditions, and a knack for and a desire to take really good care of people. All of those things make for a dependable combination when you’re a rider wanting to do your best at a race far from home.

When he purchased the company from Wheat Ridge Cyclery owner (and former Tour de France rider) Ron Kiefel, riders in the Boulder/Denver area viewed Pro Bike Express almost exclusively as a bike-transportation service. However, Smith has staffed up for 2013 and offers “concierge service” as well as transportation of bikes, spare wheels, and gear bags. His primary business is offering bike transport and services to triathletes down to the point of hanging up dripping wetsuits dumped in transition zones. Cyclocross also is a natural choice, due to its requirement for multiple bikes and wheel/tire choices, as well as the high amount of maintenance required to deal with fickle environmental conditions. But Smith, if requested by enough paying customers, will travel to and from anywhere in the U.S. for any bike event, and he will be willing to take care of those customers like they are professional athletes.

Emphasizing that he does much more than just transport bikes, Smith brought his truck and trailer to numerous Colorado cyclocross races this year and set up his enclosed, heated tents with trainers lined up inside for riders to use. In a hurry to get to your start, and your number’s not pinned on yet? Your shifter suddenly has stopped working? Need a last-minute change in tire pressure? Smith and, often, his assistant Chandler Snyder of Snyder Cycling Services (http://www.snydercyclingservices.com/), were there to assist any rider with any need they might have. Smith tripled his crew for cyclocross nationals and worlds this year, bringing along bike mechanics Snyder and Chris Fuller, who were always willing to do whatever was needed, from changing out gummed-up cables and fried brake pads, to being the actual pit crew for riders without one.

While at most events, including the 2012 cyclocross nationals in Madison, Wisc., Smith sets up interconnected tents with propane heaters inside. At the 2013 cyclocross nationals — at the same Verona venue outside Madison — the accommodations were considerably more plush. Planning well ahead for the 22 Colorado riders and their 46 bikes he would be delivering and taking care of, Smith rented a large barn immediately adjacent the race site. So while even riders on well-sponsored teams were slopping around in the cold mire in tents set up in a muddy field used as a parking lot, those who had employed Pro Bike Express’s services were indoors in a large, heated building.

Inside, Smith and his crew had set up a small, full-service bike shop staffed by Snyder. They had also set up bike parking for dozens of bikes, and even separate women’s and men’s heated, enclosed changing rooms!

As well as a place to warm up on trainers, the Pro Bike Express barn was a place to hang out on folding chairs around a heater and discuss the day’s events.

When disc brakes failed in thin, soupy mud, or when cantilevers froze and clogged in sticky, freezing mud, or if cables stopped sliding freely, Snyder quickly came to the rescue, replacing parts as needed and relieving a rider’s anxiety by giving him or her a fully-functioning bike in a jiffy. And when one female rider’s pit crew went home early, Snyder and Smith were in the pit for the elite women’s race, taking care of her as if she were Katie Compton or Georgia Gould.

For the masters cyclocross world championships in Louisville, Ky., a few weeks later, Pro Bike Express took care of 68 bikes and their owners. That was “a lot of cats to herd,” Smith said. Of those 68 bikes, he transported 59 from Colorado and needed to employ an additional truck to do so. Smith also had four bikes from South Dakota, three from Hollywood, and two from Quebec. The riders from outside of Colorado didn’t use the transportation service; rather, they were just paying to use Pro Bike Express’s other services, like tents, trainers, heaters, bike repair and pit service, “and the only coffee that was available” at the venue, according to Smith.

Smith also took care of details that riders might not even think of, and since he arrived at the venue before many riders in his care had even left home, he could provide the occasional advance heads-up. For instance, he warned his riders ahead of time about the cost of credentials required to work in the pit area during the masters races, a detail that turned out to be a surprise for many other competitors and their friends who had offered to pit for them.

The conditions during the week of masters worlds were challenging in Louisville, which featured hurricane-force winds wreaking havoc on tents and course tape, and torrential rains creating a mudfest and stuck vehicles, to frozen power washers that had become as useful as enormous paper weights in the flooded pits, to freezing mud adhering so strongly that it turned bikes into brown ice sculptures, stopped derailleurs from working, and had to be chipped off of frames, components and deep-section carbon wheels. And of course, a rising river forced organizers to compress the elite events into a single day. All in all, Smith said, “Worlds was great, with a four-season week of weather going from warm to rain to snow and cold. It was exhausting, but I had so much fun in supporting and pitting that I would do it again for sure.”

Where the emphasis for consumers of Pro Bike Express used to be almost exclusively on the “bike express” part, now it has also swung toward the “pro” part. Being taken care of like an elite rider is something that age-group competitors can definitely get used to. A group of Colorado riders is already starting to assemble to go with Smith to the Providence Cyclo-cross Festival from Oct. 4-6. Smith had nothing going on that month, and when riders approached him about it, he “thought it would be a good excuse for a road trip to the east coast.” Driving across the country, especially in a big rig, is not my idea of a good time, but it’s fortunate for weekend racers with jobs that it is for Wesley Smith.

We’ve received a number of e-mails recently asking about drivetrain compatibility. Some readers are checking in on Shimano 9000 compatibility and others are piecing together Campagnolo or SRAM drivetrains. This week, I will address a few of these letters.

Campy 11/10-speed mating

Dear Lennard,
Can an 11-speed Campy crank (53/39) work with a Campy 10-speed system without problems or do you need to change the crank and/or chainrings?
—Roger

Dear Roger,
I’ve done it a number of times with no problems. For instance, I set up a cyclocross bike with Campy 11-speed cranks and Campy 10-speed drivetrain for my daughter, and she never had a front shifting issue throughout the summer and the ’cross season, including in the sticky, freezing mud of the elite women’s race at cyclocross nationals in Verona, Wisconsin, where she, like most riders, was pitting twice per lap.

Yes, it will work fine.
―Lennard

Worn out G-springs

Dear Lennard,
I currently have 9-speed Record shifters, possibly 2000 model, I think — the very first models with carbon blades. The rear derailleur is the early 10-speed model, the first carbon model, but the pulley holders, front and back, are alloy, also around 2000 I think. Upshifts with the paddle are smooth on the 9-speed Campagnolo cassette, but downshifts with the thumb button seem to shift too far and need to be trimmed with the paddle. I’ve tried the barrel adjusters to slacken and tighten the cable, but can’t seem to remedy the problem. Is it a compatibility problem or can it be adjusted by more careful attention to the barrel adjusters?
—Ben

Dear Ben,
I doubt it’s a compatibility problem. I think your G-springs are toast. Replace those and I’ll bet it will work fine.

The G-springs are little springs shaped like a capital “G” inside of the lever. They stop the index gear inside the lever that determines how much cable is let out with each shift. As the G-springs wear, they flatten and don’t spring as forcefully into each valley of the index gear. If they can’t stop the index gear precisely, it will rotate a bit further than it ought to and let more cable out than it is designed to. If your lever is that old, I’m betting that’s what’s going on.

Instructions for overhauling that lever and replacing the G-springs (which are available from bike shops) are in any edition of my book, Zinn and the Art of Road Bike Maintenance.
―Lennard

(Not) cutting Ultegra Di2 wires

Dear Lennard,
I have a Litespeed Titanium frame that I am adapting an Ultegra Di2 shift group to. I’m having two issues. First, the Shimano wire cover set will not stick to the frame and, second, the wires to the front and rear derailleur are 5cm too long.

Can you offer any suggestions to correct these problems? Can the wires be cut or folded?
—Ken

Dear Ken,
Don’t cut the wires!

Take up any wire slack in the Di2 Junction B looping pegs (under the cover); you can wind 120mm of slack into it. Bolt Junction B to the threaded cable-guide hole under the bottom bracket shell with 1.5–2.0 N-m of torque. This is explained in the newly released (yay!) fourth edition of Zinn and the Art of Road Bike Maintenance.

I’m sure you can figure out something to tape or zip-tie your wires down. I’ll bet it’s just that it won’t stick to the coating of Lemon Pledge, WD-40, or other oil or wax that is traditionally applied to a titanium frame after bead blasting or Scotchbriting; oil or wax is put on the frame to prevent oily fingers touching the frame leaving fingerprints.
―Lennard

Matching up new and old Dura-Ace

Dear Lennard,
Will the new Dura-Ace 9000 derailleurs (front and rear) work with previous Dura-Ace shifters?

I’d like to upgrade components but wanted to do it a few at a time, and since the new 9000 shifters are very pricey, I’d like to be able to do those last.
—Scott

Dear Scott,
No, they won’t work together. There will be zero stroke compatibility between the shifters and either the front or rear derailleur.
―Lennard

SRAM and Rotor

Dear Lennard,
My bike is equipped with SRAM Apex, but I ‘m looking at the Rotor Q crankset. Do I need to change anything else if I install the Rotor Q, or will it work with the SRAM components?
—Bryan

Dear Bryan,
The Rotor Q crank will work fine with your SRAM Apex drivetrain.
―Lennard

Replacing Ultegra 6500 brakes

Dear Lennard,
I have an Ultegra 6500 9-speed groupset on one of my bikes and need to replace a rear brake caliper. I am having trouble locating a replacement at my LBS and they do not seem to be of much help. Any suggestions as to what would be compatible that is easily obtainable via the Internet?
—Marco

Dear Marco,
The new Ultegra 6700 and Dura-Ace 7900 and 9000 brake calipers will not work well with your levers, as the calipers are designed with higher leverage to mate with a low-leverage lever.

However, basically any other road brake in the world will work fine with your Ultegra 6500 lever.
―Lennard

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

This week, I’ll take a look at why, exactly, riding in cold temperatures feels so much harder than in warm temperatures. The topic ties back to a VeloNote I wrote in the March 2013 issue of Velo magazine. After hearing feedback from a number of aerodynamics experts and others in the cycling industry, the topic deserves a little more examination. It turns out the resistance we feel when the mercury dips isn’t all mental, not even close.

Dear Lennard,
Living North of the 45th parallel, I find myself riding a good portion of the winter season at temperatures at or below 25 degrees Fahrenheit. Having a general understanding of the relationship of temperature and density, I was wondering if there is any measurable effect on a rider’s effort as the temperature decreases from, let’s say, 75 degrees Fahrenheit to 25 degrees Fahrenheit? My personal observation is that it sure seems harder in the cold than in the warm, but this could be my mind telling me I’m crazy for being out and to get inside and enjoy the fire.
—Eric

Dear Eric,
I answered this question in a recent issue of Velo magazine. Since many readers of this will just be coming off a lot of cold-weather riding, and some are still in it for some time, I’m going to run a few more answers to this question, as well as the one that I put in the magazine.

Aerodynamicist Len Brownlie wrote:

You raise an interesting question and you’re observations are correct. The drag force on a cyclist is provided by the following equation: D = ½ p V2 Ap Cd where D is the drag force (N); p is the air density (kg/m3); Ap is the frontal area of the cyclist (m2) and Cd is the drag coefficient (dimensionless).

As you mentioned, air density is affected by temperature, pressure, and also by humidity. Temperature has a much more pronounced effect on air density than humidity: cold air contains more molecules per cubic meter. If the air pressure is constant at 1000 kPa, then the air density at 25 degrees Celcius (77 degrees Fahrenheit) will be around 1.169 kg/m3 while at -5 degrees Celcius (23 degrees Fahrenheit) the air density will be 1.3011 kg/m3 — about 10-percent higher, and the drag would also be increased by 10 percent.

So, on a cold day, you would need to work harder to maintain the same speed because the air density is higher than on a warm summer day. Additionally, if the relative humidity in the summer is 50 percent and near zero percent in the winter, then the air density would be increased by up to an additional 0.5 percent in the dry air of winter.

Using the Ap (0.43 m2) and Cd (0.54) of an amateur time trialist and assuming the cyclist would complete a 40km time trial in 58:37 in the summer, the same cyclist, generating the same power, would take 60 minutes to complete the race in the winter. Thus, the 10-percent increase in air density would equate to a 2.77-percent decline in performance.

If you wear additional clothing in the winter, then your increased frontal area will also increase your drag and slow you down.

Physiologically, depending on the distance of the ride, clothing worn, and wind chill, it is possible that your leg muscles may not be operating at an ideal temperature — a one-percent decline in local muscle temperature may reduce muscle force generation by up to 10 percent, which would also make the winter rides feel harder. The decrement in muscle force generation occurs despite an increase in energy cost as biochemical reactions within the muscle slow down and nerve conduction and fiber recruitment of the muscle also take longer, so that additional motor unit recruitment is required to generate the same force — leading to higher perceived strain for a given workload.

So, overall, winter rides are tougher, but, if you can handle them, they also provide additional training stimuli and are excellent training sessions.

As an aside, if you ride in an indoor velodrome where the air temperature is relatively constant, variations in the atmospheric pressure may affect race times. Atmospheric pressure normally varies between 980 and 1050 mbar (kPa). A 4km Individual Pursuit that required six minutes to complete on a bright, sunny day (high atmospheric pressure) might only take 5:54.7 to complete if there were a storm outside (low atmospheric pressure).
—Len Brownlie, Ph.D, www.aerosportsresearch.com

Cycling icon Georgena Terry wrote:

The March issue of Velo’s Tech Talk had a question from a reader wondering why riding in cold weather feels hard.

In addition to the reasons you cited, another is vasoconstriction, the constricting of blood vessels in cold weather. Cycling Weekly recently ran an article about cold weather riding and quoted to Dr. Mark Garcia, who noted, “your heart will be working very hard to pump the blood round your body due to this increased vascular resistance and the subsequent increase in blood pressure. The knock-on effect is fatigue.”
—Georgena

And this is the answer that I ran in Velo, from aerodynamicist Chet Wisner:

You have my admiration for having the fortitude to ride in these conditions. The drag you experience at 25 degrees Fahrenheit is about 10-percent greater than you would experience at 75 degrees Fahrenheit. This is approximately equivalent to the difference between riding at 20 mph and increasing your speed to 21 mph. Making things even more challenging is the wind chill of -22 degrees Fahrenheit your body is experiencing as you cruise along at 20 mph. I’m sure you’re already aware that protecting all exposed flesh under these conditions is imperative to preventing frostbite during even short exposures.

The physics behind this is based on the fact that aerodynamic drag is proportional to air density, and, in turn, air density is inversely proportional to absolute temperature. For a temperature in Fahrenheit degrees, the absolute temperature is calculated in Rankine degrees by adding 460 degrees. So, 25 degrees Fahrenheit is 485 degrees Rankine. Similarly, 75 degrees Fahrenheit is 535 degrees Rankine. The ratio of these Rankine temperatures is 1.10, which means the air on your cold rides is 10-percent denser than on your 75-degree rides. Since drag is proportional to air density, the drag you experience is also about 10-percent greater on the cold rides.

Drag is also proportional to the square of the speed with which the air passes by you and your bike. If there is no wind and you are traveling 20 mph, then increase your speed to 21 mph (or pick up a 1 mph headwind), the drag increases by the square of the speed. The ratio of the squares of 21 mph and 20 mph is about 1.10. So, this increase would have the same effect on the drag you are pedaling to overcome as the 50-degree Fahrenheit temperature difference.

So, you can take some consolation on your cold rides that it really is harder for you to pedal than your more fortunate cohorts in warmer climes.
—Chet Wisner, Ambient Air Technologies, LLC

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

BOULDER, Colorado (VN) — One of the world’s top automotive and bicycle tire brands is absent from the WorldTour in 2013, but Michelin is content to wait for the world’s top cycling teams to come knocking. That is, after all, how the French manufacturer runs its coveted Le Mans auto-racing program.

At the invitation of Michelin, I was at the Sebring International Raceway in early February for the introduction of its new bicycle tires. It seemed an odd choice of venue until meeting Silvia Mammone, the motorsports marketing manager for Michelin and BF Goodrich (which is owned by Michelin). Mammone grew up in Montreal, working in her father’s bicycle shop, and her dream was to bring her two worlds of motorsports and bicycles together. She realized that dream through a bicycle tire product introduction at this legendary automobile racetrack.

Mammone said that 85 percent of the cars in the top-level P1, P2, and GT classes in the American Le Mans Series race on Michelin tires. This is not because Michelin pays them to race on its tires or even gives them tires. Quite the contrary: the teams pay for the tires. Not only do they pay for them, but they don’t get to even own them — they lease the tires and must return them. They do this because they think their chances of winning will be enhanced by doing so.

According to chief engineer Ken Payne, auto-racing teams want Michelin tires not only because they perform well, but also because their cars can go long between tire changes. Motorsports programming manager Bob Williams says that teams can always “double stint” on Michelins — go at least two tanks of gas before needing to change tires, whereas other tire brands often require a change at every fueling pit stop. Sometimes Michelin-equipped cars can even triple-, quad-, or quint-stint, going as long as five tanks of gas before changing tires. This is critical in Le Mans racing because teams are not allowed to change tires while they are refueling, out of concern that a spark from a tool may cause an explosion. So, tire-change time, usually about 12 seconds, is additional time spent in the pit. It is very hard to make up 12 seconds in a car race like Sebring, and a gap of 60 seconds is almost impossible to make up.

The fees teams pay for tires does not begin to cover the costs Michelin accrues in its auto racing program, however. Michelin takes the loss, however, for the knowledge it can glean to make better tires, just as car companies use these events to improve the cars they sell to consumers. (In 2012, Audi swept the podium at the 24 Hours of Le Mans with the top two being 4WD hybrid diesels, technology certainly headed for the street.) Michelin was the first to commercialize radial tires, and their greater fuel economy, consistent diameter, and durability carried them to race victories and the position of standard-bearer for all passenger-car tires. While that’s the most profound example, there are constant improvements put to the test in endurance events like Sebring and Le Mans.

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

We’ve received a lot of mail related to VeloLab’s chain lube test in the March 2013 edition of Velo magazine. After answering rueful reader questions lamenting the results, which showed that paraffin wax was the most efficient lube (we didn’t test for durability, merely power savings), this week I’ll address one reader who asked about the importance of regular maintenance versus lube choice.

The numbers on lube efficiency over distance

Dear Lennard,
I agree with you that regularly cleaning the drivetrain and lubing probably makes more difference than what lube you use. I spend 10 minutes wiping my road bike down after each ride, including drivetrain components, and lube the chain about every 80-130 miles. I measure my chain with a chain checker and get 4000-5000 miles out of each one. I can see how lube efficiency might be important for racers where seconds could make a difference in a race. But it is unclear how relevant this is to most riders.

So, my question is, if all variables are identical except for the lube, and you rode exactly 10 miles in dry conditions at a given power output (I believe the efficiency test was at 250 watts), how much sooner would you reach 10 miles using paraffin versus ProLink, my current preferred lube?
—Stanley

Dear Stanley,
Here is the answer Jason Smith of Friction Facts, who performed our Velo chain lube test, came up with:

The quick and easy way to answer the question would be to use the analyticalcycling.com (AC) site. Based on the lube test results, at 250W, paraffin consumes 4.82W. ProLink consumes 7.23W, a difference of 2.41W. When using the AC formulas, I’ll plug in 250.00W and 247.59W and look at the difference. Now, this is not exactly the case, since the rider is actually putting out 250W in both cases, and the 5W difference is lost in the drivetrain, but as a place to start, I’m assuming the rider is putting out 2.41 fewer watts in order to use the AC plug-n-play formulas.

250 watts = 25.12 mph; 247.59 watts = 25.03 mph; a difference of 0.09 mph

Now, to perform my calculations, I’d like to look at two scenarios: the two limits of speed difference. Again using 250.00W and 247.59W as rider outputs, assuming the only drag slowing the rider down was purely mechanical (bearings and tire rolling resistance) and no aero drag, then the relationship between mechanical drag and speed would be linear. Therefore the speed difference would be 247.59/250.00 x 25.12 = 24.88 mph; a difference of 0.24 mph.

For a second scenario, assume zero-percent mechanical, and 100-percent aero drag. The relationship between aero drag power and speed is P=1/2V*3. In this case, a 2.41W difference equates to a 0.82W difference when viewed linearly. 249.18/250.00 x 25.12 = 25.04 mph; a difference of 0.08 mph

(Of course, these two scenarios would never happen, but they set up the limits, according to my formulas.)

Now, you’ll note that the AC difference falls between my two scenarios. Since the AC number is pretty close to the 100-percent pure aero scenario, I speculate they are using a high aero ratio when looking at overall contributions of aero versus mechanical drag.

For the next step, I’m going to calculate my own ratios using the data I have available for mechanical drag at 250W output, and 25mph:
Chain and pulleys 8W average
Pedals 0.75W average
Bottom bracket 1W average (not tested yet, but this is where I feel they will be coming in)
Two hubs 4W total (not tested yet, but I feel hubs will be running 1-3W each)
Two tires 60W (30W each). (I’d use your Velo test data, but I can’t find that issue in my pile of Velo mags.)

The total mechanical friction wattage consumption in this case would be approximately 74 watts, and aero
wattage would be 176 watts (250-74).

The ratio is approximately 30-70-percent, given this example, at 250W rider output, and 25 mph.

Using this ratio, and using a 0.08 mph to a 0.24 mph bandwidth, knowing the 30-percent mechanical drag is linear, and the 70-percent aero drag is ½ cubed, a 2.41W difference in mechanical friction would amount to a 0.10 mph difference.

And voila, my calculations show 250 watts equals 25.12 mph; 247.59 watts equals 25.02 mph.

To get back to the reader’s question. A 2.41W difference due to chain friction equals a 0.10 mph difference. Over a 10-mile ride, the time difference is 5.73 seconds.
—Jason

I welcome others of you so motivated to work on this calculation as well. This is considerably more time difference than I would have guessed, and I must admit being dubious.

If this really is the case, it could be a significant difference in a time trial or other individual events.
―Lennard

Campy master link solutions

Dear Lennard,
I’ve been searching for a master link for my Campy 10-speed chain. Does this item exist to your knowledge? Without, it is quite expensive to remove and re-install the chain.
—Tim

Dear Tim,
Wippermann makes a Campy-specific 10-speed master link. That said, any 10-speed master link will work; I run Campy 10-speed on both of my cyclocross bikes, with master links. While I have run plenty of non-Campy 10-speed chains on them without problems, I’ve also run Campy chains with Wippermann, KMC, and SRAM master links (for the latter, you need the Park master link pliers to open it since it’s not intended to be opened).
―Lennard

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

This week’s column is all about wheels — building them, repairing them, and keeping tires on them. On a related note, we’re happy to announce that the 520-page fourth edition of Lennard’s Zinn & the Art of Road Bike Maintenance book is out now and available at bookstores, bike shops, and online.

More spoke holes than I know what to do with

Dear Lennard,
While my initial reaction is, “No way!” I then ask why, and the question gets deeper…

Could I use a Chris King 32-hole hub with a 24-spoke rim?

If I do the math, I see some common denominators that make me question my initial conclusion…
—Davo

Dear Davo,
I used to do this many years ago on lots of team wheels I built in the mid- to late 1980s for the Zinn-Alfalfa’s women’s team I used to sponsor, using Mavic 24-hole rims and either Shimano or Mavic 32-hole hubs. It always worked fine. Even in those days before deep-section rims, with a women’s team, 32-hole wheels were generally overkill for all but a few of the larger riders.
―Lennard

Losing my touch?

Dear Lennard,
I’m an experienced wheelbuilder (over 150 builds) who worked his way through college as a mechanic. However, since graduating five years ago, I haven’t built a wheel until this past week. I also have never used tubeless tires until this week. I built my new mountain wheels (26-inch), got them all tensioned up, and mounted the tires. After mounting and airing up the tubeless tires, I had a noticeable difference in spoke tension (they loosened up!) and I had to go back and re-tension my wheels.

What gives? Is this normal with tubeless or has the five years off really diminished my wheelbuilding skills that badly? I used quality components (King hubs, DT spokes, nips, and rim, with a DT tubeless conversion kit and Maxxis LUST tires), so that shouldn’t be the issue. I’m just wondering if I screwed up my new wheelset. Both front and rear needed about a quarter-turn more tension per spoke to get the tension right.
—Jared

Dear Jared,
Yes, that’s normal. Every wheel’s spoke tension decreases with increasing tire pressure.

In fact, Easton sells its rear wheels out of dish for this reason. Easton says, “Our spec is designed to put the wheel towards the non-drive side for dish because when the tire is inflated on a rear wheel it will decrease the tension on the wheel causing it to pull toward the drive side. That is not the case on a front wheel as the tension is equal.”
―Lennard

Carbon peeling

Dear Lennard,
I recently bought a used set of carbon tubulars, with tires mounted. To be sure of the glue job underneath the tire, I am removing the tires and re-gluing them. The tires lifted off the rims fairly easily, but it looks like they took a layer of the rims off in a few spots; there’s some carbon stuck to the base tape of the tire. The biggest spot is about 2 inches long and the width of the base tape, with a few other smaller spots around the base tape. I assume that I will need to glue new tires on, but is this a problem for the rim?
—Ryan

Dear Ryan,
Pulling off of some fibers in the top layer of carbon on the rim bed happens sometimes upon tire removal, and it’s impossible to judge at this distance how much your rim is compromised. I have often gone ahead and glued another tire on over some small patches where fibers had torn out of the rim bed, and I’ve never had a carbon tubular rim failure. However, yours is a bigger patch than I’ve ever seen.

Consult the rim manufacturer.
―Lennard

Blowing tires

Dear Lennard,
A riding buddy has had two Hutchinson Fusion Kevlar bead tires blow off rims on the same steep downhill — one on a Ksyrium rim, and one on a Neuvation. This downhill is a real brake burner, so he’s wondering if he could have heated the tire to the point where it would blow off, or is this more likely just a mounting error, a tire not seated perfectly. His concern is with the rims, but since they expand with heat, I would expect that would help, not hurt.
—Steve

Dear Steve,
Well, the most common reason a tire blows off is because there is some inner tube sticking out under the bead. Avoid this by always starting and finishing at the valve stem when dismounting and mounting tires.

It could also have been a tolerance run-out issue — too big on the tire bead, or right on the big end of spec, and too small on the rims, or right on the small end of spec.
―Lennard