VeloNews.com » Lennard Zinn http://velonews.competitor.com Competitive Cycling News, Race Results and Bike Reviews Wed, 28 Jan 2015 21:39:38 +0000 en-US hourly 1 http://wordpress.org/?v=4.0.1 Technical FAQ: Cracked carbon seatposts and more http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-cracked-carbon-seatposts_359422 http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-cracked-carbon-seatposts_359422#comments Tue, 27 Jan 2015 14:18:24 +0000 http://velonews.competitor.com/?p=359422

Harry’s cracked carbon seatpost.

Lennard Zinn addresses questions about cracked carbon seatposts and the compatibility between drivetrain parts

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Harry’s cracked carbon seatpost.

A cracked carbon seatpost

Dear Lennard,
I have a cracked carbon fiber seatpost. Photo [above]. This is the second in four months, and this one failed after less than 25 rides. Both cracked in the seat vertical way. The frame is a 2006 custom-sized Serotta titanium that has over 40,000 miles, and the previous seatpost (also carbon) was the original. The questions I have are:

— Any ideas why this might be happening?
— Should I get a replacement titanium or aluminum seatpost? It seems to me another carbon one will fail, too.
— Any considerations where replacing with ti or aluminum?
— Harry

Dear Harry,
Yes, I certainly do have an opinion about why that has happened.

Carbon fibers are very strong, and, while they can be quite flexible when dry, they become brittle when cured with resin into a matrix. In this case, it looks to me like the seat clamp at the top of the seat tube pinched the corners of the seat-tube slot into the fibers. Carbon fibers cannot take being crushed like that, and the carbon layers will crack and delaminate in response.

There are a number of ways to avoid this, all of which are intended to avoid the stackup of the slot and the tabs of the binder clamp together. If your frame has the binder tabs welded on (rather than a separate band clamp), and your bike takes a 27.2mm seatpost, you are out of luck and should look for a different material other than carbon fiber for your seatpost. (I suppose there is one option with this situation, and that is to cut and file off the binder ears so that you can use a removable binder clamp on it, and then follow Option 2, below.)

With welded-on binder tabs there is only one option to use a carbon post — and that is only as long as the seatpost diameter is larger than 27.2mm. However, if you have a removable seatpost clamp that slips over the top of the seat tube, you have other options.

Option 1
If you have a seat tube with an inner diameter of 28.6mm or larger, then you can use a carbon 27.2mm seatpost along with a slotted shim sleeve that will bring it up to the inner diameter of your seat tube. When you slide the seatpost into the sleeve and in turn slide the whole shebang into the seat tube, make sure you rotate the slot of the shim sleeve so it is on the opposite side from the slot in the seat tube. That way, as the binder clamp is tightened and its corners push inward, the sleeve distributes the load away from the high stress concentration at the top of the seat-tube slot that cracked your seatpost.

Option 2
If you have a removable seat binder clamp, rotate it so that its slot is on the opposite side from the slot in the seat tube. In other words, the binder bolt will be in front of the seatpost, not behind it. This way, the binder clamp’s clamping force will be distributed around a large area, and there will not be a stress concentration at the corners of the seat-tube slot. A variation on this is to use a binder clamp with an angled slot; these are made specifically to address this problem and avoid pinching in at the top of the seat-tube slot.

Using Options 1 and 2 together will further decrease the stress concentration at the top of the seat-tube slot.

As for a preference between a titanium and an aluminum seatpost, I don’t have one. Yes, a titanium one could look very nice with your titanium frame. On the other hand, with aluminum seatposts the price is generally lower, there are far more options, and you can pick the post based on your preferred saddle-rail clamp atop the post.
― Lennard

Cutting a carbon seatpost

Dear Lennard,
I have a carbon seatpost that is way too long for my frame size and would like to cut it down because it’s hard to install and perhaps save a little weight.

How much seatpost is recommended inside the seat tube (below my required seat height) to keep it safe for riding?
— Sam

Dear Sam,
Make sure you have at least four inches (100mm) inside the frame. That should be sufficient for most bikes, but ensure that it is also long enough to extend below the intersection with the seatstays and top tube.
― Lennard

Shimano Ultegra compatibility

Dear Lennard,
I have a Shimano Ultegra-equipped Cervelo R3 and my STI shifters are of the old variety (exposed cables not under the bar wrap). My friend offered me his new Shimano 6703 shifters that he no longer needs. Will the Shimano 6703 left shifter (being meant for a triple) be compatible with my compact double (50-34 teeth)? I have upgraded my front and rear derailleurs in the last year to Shimano 6700 due to other reasons and was hoping this would work. What do you think?
Robert

Dear Robert,
That system could be adjusted to be rideable, perhaps even raceable, but it can’t work like either system was intended to work, because you won’t be able to trim the derailleur’s position to avoid chain rub in cross gears at both ends. The left ST-6700 double shifter has a trim position on both chainrings, but the left ST-6703 triple lever has no trim adjustment over the middle chainring, which now becomes either the inner-chainring position or the outer-chainring position when used on a double. So whether you attempt to use outer/middle position clicks, or middle/inner position clicks for running it as double shift lever, you will almost certainly not be able to get an adjustment without chain rub on the front-derailleur cage in all cross-chain combinations. That may be fine for you, and the price is certainly right.
― Lennard

SRAM road/MTB compatibility

Dear Lennard,
I stumbled upon an older post of yours regarding 10-/11-speed compatibility. In a response, you mentioned that, “SRAM did not change the cable pull ratio when going from 10-speed to 11-speed, so a 10-speed SRAM road rear derailleur will work quite well with an 11-speed SRAM road shifter.” This sparked my interest! I am running a 10-speed SRAM Rival rear shifter with an inline barrel adjuster, a SRAM X5 type 2 rear derailleur, a SRAM 11-32 10-speed cassette, SRAM 10-speed chain and a Raceface narrow-wide ring on my CX rig as a budget, CX1-style build. In my research, folks who’d set their bike up this way had great luck, but claimed it would only work with a 10-speed setup. I can attest that it indeed has work flawlessly. That said, if the pull between SRAM 11-speed and 10-speed road shifters is the same, with an 11-speed chain and cassette, can a SRAM X5 type 2 rear derailleur be paired up with a Rival 22 (11-speed) shifter?
— Ryan

Dear Ryan,
Yes it can, because SRAM also maintains the same cable-pull ratio on both its road and MTB rear derailleurs, other than 11-speed MTB. So your 11-speed road shifter/10-speed MTB rear derailleur combination will work fine, just don’t even think about trying to pair any road shifter with an XX1, X1, or X01 rear derailleur! This also applies to X01 7-speed and X01 10-speed rear derailleurs; their cable-pull ratio is the same as other SRAM X-Horizon MTB rear derailleurs (which are all 11-speed other than these two exceptions).
― Lennard

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Technical FAQ: Even more on disc brakes in extreme cold http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-disc-brakes-extreme-cold_358757 http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-disc-brakes-extreme-cold_358757#comments Tue, 20 Jan 2015 18:30:18 +0000 http://velonews.competitor.com/?p=358757

Disc brake internals, as diagrammed in "Zinn and the Art of Mountain Bike Maintenance."

Lennard Zinn gleans even more information from disc brake companies about how performance is affected by very cold temperatures

The post Technical FAQ: Even more on disc brakes in extreme cold appeared first on VeloNews.com.

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Disc brake internals, as diagrammed in "Zinn and the Art of Mountain Bike Maintenance."

When I posted these answers about riding disc brakes in extreme cold, I figured that would be enough to say about it. But even after posting a lot of opinions by brake manufacturers last week, I continued to get some responses from other brake companies that either covered new ground or had a different take on the subject. Here are some of them.

First, I want to explain the mechanism for pad retraction in a hydraulic disc brake to ensure that some of the comments below are more widely understood.

Pistons in most hydraulic disc brakes are pulled back into the cylinder upon release of the brake lever by the untwisting of an O-ring seal that is square in cross section. This “square seal” or “quad ring” surrounds the waist of the piston and sits in a groove running around the bore of the piston cylinder. [You can see the square seal in cross-section as well as in the exploded view of a caliper in the drawings from “Zinn and the Art of Mountain Bike Maintenance” shown above.] The rear wall of this groove is generally perpendicular to the cylinder wall, while the leading wall of the groove often is at a lower angle to allow the square seal to flex outward against it.

When fluid is forced in behind the piston by squeezing the lever, the piston moves outward, and the internal diameter of the square seal will move with it, causing the seal to twist. When the rider releases the lever and hence releases the hydraulic pressure, the square seal will untwist back to its original configuration, bringing the piston back with it — as long as the seal holds, that is.

The flexibility of the square seal’s rubbery material is quantified by its “durometer,” a measure of how forcefully it pushes back against pressure applied to it. And durometer of an elastic material is affected by temperature.

Extreme cold can inhibit piston retraction in two different ways. First, it can make the square seal stiffer (i.e., increase its durometer) so it is less able to twist. Second, low temperature can shrink the materials in the caliper — the metal of the caliper body, the metal, ceramic, or composite material of the pistons, and the rubber (or rubbery material) of the square seals. This shrinkage will happen at different rates in the different materials and will thus affect their fit against each other.

Dirt around the pistons has a similar effect in reducing pad retraction by causing leaks around the seal and by increasing friction, since the piston is being asked to slide on grit. If you complicate the job of a dirty piston seal by asking it to perform in extreme cold, the combination can result in abysmal pad retraction. And seals that have become loose due to low temperatures are more susceptible to contamination from dirt.
― Lennard

From FSA:
Thank you for tackling this topic. As fat bikes become more and more popular, it’ll be necessary to explain to folks what is happening with their brakes in the cold. I’ve been testing disc brakes in the Wisconsin winters since 1998 and still can’t believe the difference in feel as the temps drop.

Your piece contains many valid points made by very experienced disc-brake veterans and riders. I completely agreed with most points and just wanted to pass on my two cents for what it’s worth.

1. The DOT-based systems will be less likely to get “sluggish” lever feel in the extreme cold, but system design will have more to do with the feel than anything.

2. The seal durometer part is kinda crap in that all the brakes I’ve ridden in the cold not only have slower retraction but also lose retraction as the pistons start slipping (lever stroke gets shorter) when the square seals get harder from the cold. Saying one is better than the other is a stretch.

3. Leaking can happen in either system, as well. Depends on the tolerances set up in the design. Oddly, cheaper brakes often are designed to have more “squeeze” with their rubber parts to compensate for looser tolerances and in turn aren’t as likely to leak as a high-end brake that is designed to have very little squeeze in order to feel light at the lever.

4. Metallic pads are for sure gonna work best, but will be noisy as hell in the cold and wet. They also need heat to melt the ice and snow, so high speeds are needed, which doesn’t happen often on fat bikes.

5. The carbon lever thing is no joke, as it won’t transfer the cold to the rider’s hands. The joke is that Tim [Abhold] at Hayes [Richardson used to be a product manager at Hayes Disc Brake -Ed.] used to give me a ton of crap when I would report that test riders wanted carbon levers for winter riding!

[It] was interesting coming from 13 years of preaching DOT fluid to folks [at Hayes] and then switching over to mineral oil with FSA’s system. [I] learned a lot from our Japanese fluid vendor, in regard to the hydraulic fluids and all the various additives that can be formulated for different applications.

We discussed cold weather specifically and played with different levels of, what I referred to as, “antifreeze” in the oils to help stabilize the fluid in cold temps. We talked about mineral oils used in airplane and snowplow hydraulics that need to be fluid down to -50F degrees. So, it is possible to make mineral oils that are amazing in the cold; the problem is keeping their boiling or flash point high enough to meet our needs and the various standards. We ended up with a very balanced fluid that keeps our brake functioning in -20F degree life-cycle testing, yet still doesn’t boil on the dyno and more importantly on the hill with big guys that go fast.
— Joel Richardson
Disc Brake Product Manager
Brand Manager for the Gravity MTB brand
Full Speed Ahead (FSA)

(Another response) from TRP:
The only thing I’d add [to Lance Larrabee’s comments] is that wintertime can make rotor and pad selection very tricky. Often we get “dry” conditions in the morning that are below freezing, followed with above-freezing wet temps later in the day; I prefer a two-piece rotor with metallic or semi-metallic pads [for this]. The metallic pads provide longer pad life, and the two-piece rotor is stiffer, mitigating resonance that can occur with wet conditions (it’s like the wet finger and wine glass trick — doesn’t work so well on your everyday drinking glass — the glass is thicker and does not vibrate/resonate/sing).
— Nick Riddle
TRP Product Designer

From Magura:
I’d recommend fully hydraulic disc brakes, no mechanical or semi-hydraulic brakes, as cables can freeze with water getting into the outer housing or the mechanical part of the caliper.

Viscosity of brake fluid or mineral oil will increase with lower temperatures, making the brake feel slow. Additionally the quad-ring in the caliper will lose elasticity with piston retraction getting smaller with lower temps up to the point, where no retraction is available anymore.

This is common on all hydraulic brakes, with some being more affected by lower temps than others.

There is a nice info on Wikipedia on brake fluid; see especially dry and wet boiling points.

Mineral oil has a boiling point of 180 to 190°C (356-374°F) and will maintain it over time, as it doesn’t attract water.

I was riding at around 0F, and my Maguras still worked. A bit slow, but still decent.
—Stefan Pahl
Magura Product Manager for Bicycles

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Technical FAQ: More on disc brakes in cold weather http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-disc-brakes-cold-weather_358172 http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-disc-brakes-cold-weather_358172#comments Tue, 13 Jan 2015 21:24:42 +0000 http://velonews.competitor.com/?p=358172

How do extremely cold temperatures affect disc brake performance? Lennard Zinn talks to manufacturers to find out the pros and cons of various designs. Photo: Caley Fretz | VeloNews.com

Lennard Zinn talks to several brake manufacturers and bike companies to find out which disc brakes work best in extreme cold

The post Technical FAQ: More on disc brakes in cold weather appeared first on VeloNews.com.

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How do extremely cold temperatures affect disc brake performance? Lennard Zinn talks to manufacturers to find out the pros and cons of various designs. Photo: Caley Fretz | VeloNews.com

There’s plenty more cold-weather riding to be done this winter. Even though 2014 was somewhere between the first and sixth warmest year on record in terms of global average, the Midwest and eastern U.S. had a colder than average winter, and 2015 started out cold there, too. We here in Colorado have traditionally been spared the freezing rain those areas get, but not this winter! Geez. I have a lot of empathy now for those farther north and east of us who have, for their entire lives, put up with this stuff freezing all over everything.

I already posted some answers to the question of what kind of disc brakes to choose for extreme cold, but there is a lot more to be said about it. Don’t be surprised if I find more to add to this in coming weeks, too!

When making purchases for this purpose, I also recommend seeking out bike shops that have employees who ride year-round in your area.

— Lennard

From Avid/SRAM:
In our testing, mineral-oil brakes are more challenged in cold (-15F and below) because of the constraints of the seal material, rather than the fluid itself. As you know, DOT brakes and mineral-oil brakes require different seal materials. We find that the brakes lose rollback at the caliper as the seals get cold, and this is what primarily tips things in favor of DOT brakes.

I would basically rank things as such: Down to around -15F, hydraulic brakes will work the best; some may develop a sluggish feel based on the quality of the product. Below that, DOT brakes will hold up better, but below -30F, if you really need to ride your bike, mechanicals [cable-actuated disc brakes] will be the most reliable — if you can move your fingers enough to pull the lever.

DOT absorbs water; this is true. The fluid is designed to do that as a way of managing air and moisture that enters any system over time.

Mineral-oil brakes still ingest water over time; however, the fluid repels this water, and it collects at low points in the system, i.e., the caliper. The caliper obviously sees higher temperatures, and since water’s boiling temp is basically 100C, this phenomenon handicaps the heat management of mineral-oil brakes.

— Paul Kantor
Avid/SRAM brake product manager

From Borealis (fat bikes):
We have had a ton of experience on a ton of different brakes, and for wet/cold areas we would recommend a DOT fluid brake, as opposed to a mineral-oil brake, like a Shimano. I love Shimano brakes, but when I rode the 988 trail brakes in the cold last year, the performance was very poor and lever feel was slow and unresponsive. I actually thought the crappy SRAM X0 brake system had better performance in cold, snowy conditions despite the loud, strange noises they make. The new SRAM guide brakes are the best multi-use brake on the market currently, in our opinion. The lever action in the cold a couple weeks ago, when it reached about 10-14 degrees F, was actually pretty good, and the braking performance of that four-piston brake is amazing with a sintered, metallic pad. Many of our Canadian and Alaskan dealers use mechanical brakes because of extreme temperatures, so it really depends on what the customer is looking for. So for cold weather, use a SRAM Guide brake, and for extreme cold we would recommend going with a cable-actuated brake like Avid’s.

— Greg Herrman
Founder, Borealis Bikes, Fatbike.com

From Hayes Disc Brakes:
– Any of the mentioned systems can be made to operate at low temps. The most important thing is that the manufacturer performs low-temperature testing and makes any necessary adjustments, which we have done for our mineral-oil brake, glycol (“DOT”) brake fluid systems, and mechanical systems.
– The biggest difference we have observed is that mineral oil has less viscosity stability in cold temperature than brake fluid. It becomes thicker, and it can exhibit a noticeably slower lever feel. Glycol fluids do this too, but to a much lesser extent, in our experience.
– Our benchmark testing has shown many manufacturers’ mineral-oil products do not seal as well as glycol fluid systems at cold temperatures. Mineral oil requires the use of a different seal material, which changes elasticity (or “durometer”) with temperature. Special design considerations must be taken to ensure proper sealing.
– All hydraulic systems will have a different feel in cold temperatures. Mostly due to the fluid viscosity and seal durometer changes, the lever will feel heavier, and the caliper piston retraction (and hence pad clearance and lever dead stroke) can change. In our testing, the glycol systems were generally more robust to temperature.
– Cable systems are generally less sensitive to temperature, but they also will have a heavier lever feel as assembly grease and any cable lubrication thickens with temperature. They also do require some exposed cable that can ice up in rare conditions, so they’re not totally impervious to weather. And even at their best, cable systems do not match the smooth, linear, and low-effort feel of a hydraulic brake system
– Cable/hydraulic systems are a way to bring a mostly hydraulic system to a drop-bar bike at a reasonable price point. But they have all the drawbacks of both hydraulic and mechanical systems and due to their complexity, I would opt for either a mechanical or hydraulic system for use in adverse weather.
– Using brakes in snow is very similar to using them in rain. The snow melts to water when in contact with the rotor, so I would recommend wet-weather pads. Most of the time, fully sintered metallic pads offer the best wet-weather performance and also perform well in snow.
– Our fleet of test riders consistently prefer carbon-fiber lever blades in cold temperature. It doesn’t conduct heat away from your fingers nearly as quickly as aluminum. It seems unlikely, but it makes a noticeable difference.

— Tim Abhold
Director of Engineering and R&D
Hayes Components

From a guru of Alaska winter endurance riding:
The first hydraulic brakes I ever saw were in the early days of the Iditabike. Those Maguras were working happily at -30F.
The hydraulics-in-the-cold story is pretty straightforward. The DOT systems behave well down to at least -50F. Mineral-oil systems show slower retraction starting in the -20s or so but still perform well as far as braking.

Riders have a variety of problems with their bikes in winter; some problems get misdiagnosed, and hydraulics are an easy target. Many dedicated winter bikes here get set up with [Avid] BB-7s [cable-actuated disc brakes] as a sort of insurance. I don’t discourage this practice.

Brakes themselves are rarely a problem in our winter conditions. The available traction on snow or ice limits braking more than the rest of the system does.

Freeze/thaw conditions, whether from the weather or from bikes going in and out of warm spaces, cause a lot of mechanical problems. Bike leaves house warm, snow thrown up by tires melts on brakes or derailleurs, then freezes as bike cools. Hydraulics are less subject to this.

Lubriplate and Castrol offer low-temperature hydraulic fluids. I’ve never explored these options, because we haven’t needed to. Looking for some quantitative information for you, I learned that Citroen and Rolls Royce use(d) mineral oil, and that Castrol makes low-temperature fluids for those systems too.

I also learned that smart brake and suspension automotive systems need fluids whose viscosities remain in a narrower range than is needed for older systems. The antilock on my cars hasn’t acted differently at -50F, underlining the fact that even basic DOT fluid is pretty temperature-invariant.

Rereading the question:
Cables will act like cables at all temps
DOT systems will be a bit less trouble-prone than mineral oil at very cold temps.

— Simon
All Weather Sports
Fairbanks, AK

From Surly:
DOT fluid is the way to go if you must use hydraulic brakes in cold temps. Mechanical brakes also work well. We spec Avid hydraulic brakes on our Ice Cream Truck specifically because they use DOT fluid. I personally prefer Shimano disc brakes for their performance attributes but I would never use them in the cold, because they have mineral oil in them.

— Peter Redin
Brand Manager – Surly Bikes

From Larry Kaatz of QBP (Minneapolis):
Even stainless steel rotors can get a little messed up with road salt (used liberally around here), and if you don’t wipe them down well after rides on roads with salty slush and/or puddle they’ll be noisy and rough at the start of your next ride. Using the brakes will clean off the rotors so that they’re quiet again, but I’m not sure what that means for the lifespan of the brake pads.

— Larry

From Lance Larrabee of TRP brakes:
With the cold spell here in Utah and most of the U.S. coinciding with our need to prove some of our new designs, TRP has recently been conducting cold weather testing on our own hydraulic disc brakes brakes as well as those of our competitors. We found at temperatures below 20F degrees, all hydraulic disc brakes in our test, both mineral-oil and DOT fluid, showed some degree of sluggish performance. We didn’t experience any catastrophic failures and all the brakes returned to normal function either as the brake heated up from friction or when the weather got above freezing.

Many fat bike riders, especially those from cold-weather states like Alaska and Minnesota, who often ride in extreme cold weather, have experienced the same symptoms and from our perspective at least, seem to have come to the consensus that mechanical disc brakes (cable) are the best option in the cold.

Following the introduction of our two-piston mechanical road/cross brake, the Spyre, we had many request to create a mountain version of Spyre specifically for fat bikes. As a result, we created a second two-piston brake to work with flat bar linear pull-type brake levers and to cope with the addition rotating mass of fat bike wheels. We named this new brake Spyke and introduced it in early 2014. In addition to the change in lever pull and strength, the Spyke has a snow/mud cover over the pads and an accordion boot to help seal the cable at the actuation arm.

If you’re creating a drop-bar winter training/commuter bike, the snow/mud cover and accordion boot can easily and inexpensively be added to our Spyre mechanical disc.

— Lance

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Technical FAQ: Weight distribution, compatibility, and more http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-weight-distribution-compatibility_357312 http://velonews.competitor.com/2015/01/bikes-and-tech/technical-faq/technical-faq-weight-distribution-compatibility_357312#comments Tue, 06 Jan 2015 14:37:08 +0000 http://velonews.competitor.com/?p=357312

Pushing your weight back while braking on a descent keeps you in control of the bike. Photo: Casey B. Gibson | www.cbgphoto.com

Lennard Zinn addresses reader questions about weight distribution on a bike, mixing cogsets, and more

The post Technical FAQ: Weight distribution, compatibility, and more appeared first on VeloNews.com.

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Pushing your weight back while braking on a descent keeps you in control of the bike. Photo: Casey B. Gibson | www.cbgphoto.com

Weight distribution on a road bike

Dear Lennard,
Decided to do a little research into weight distribution. Doesn’t seem to be much out there. Found lightly to unsupported answers between 55/45 percent (rear/front) to 70/30 percent. Will two scales be an accurate way to ascertain this? Would love to hear what you have to say about it.
— Scott

Dear Scott,
I think the reason there is not much out there is because people say things about it but rarely actually measure it. I’m convinced that anybody who says the weight distribution on a road bike should be 55 percent on the rear wheel and 45 percent on the front (or 50/50, or anything in the realm below 60 percent on the rear wheel) never actually measured it. Either that, or they were built a lot differently than anybody I’ve ever measured; one would have to have a very big, heavy head, among other things. (I’m not talking aero bars, just standard drop bars.)

It’s actually quite easy to measure, and you only need one scale and a block of wood or book of the same thickness as the scale. Put the scale under one wheel and the block or book under the other. Read off the scale reading. Put the scale under the other wheel; same with the block or book. Record this scale reading as well.

Divide the rear reading by the sum of the front and rear readings to get the percentage on the rear wheel. Subtract this from 100 to get the front percentage, or perform the same calculation with the front wheel.

Don’t be surprised if it comes out 70/30.

While it may seem that having as close to even weight distribution over the wheels is a noble goal, it is not worth sacrificing the fit and handling characteristics that you would have to in order to achieve it. Making the chainstays so long, the saddle position so far forward, the stem so long, the top tube so short, the head angle so steep and fork rake so short to achieve 55/45 or so weight distribution, which would also result in a lot of overlap of the foot with the front tire, would actually not lead to good bike handling.

Bike handling works fine with two-thirds or so of the weight on the rear wheel; don’t try to get more toward 50/50 or 55/45. Think about it: you know when the weight on the front gets up around 50 percent, and you don’t like it. Think of an aero bike with a short top tube, long aero bar, super-steep seat angle, and forward saddle position; you instinctively know that’s not what you’d want to ride a tight criterium course on. Or think of when you slam on your brakes on a steep downhill for a sharp corner and your weight shifts way forward; it doesn’t feel good, and you try very hard to push your butt way back on the seat— and behind the seat, even — before you get to the corner.
― Lennard

Compatibility questions

Dear Lennard,
I’ve seen several of your posts about using a 9-speed MTB rear derailleur with a 10-speed Shimano mechanical group to enable use of an 11-32 cassette. Will this work with all 9-speed MTB rear derailleurs or are there particular models to use?
— Stuart

Dear Stuart,
Any Shimano 9-speed mountain-bike (or road bike) rear derailleur works with any Shimano 10-speed road shifter.
― Lennard

Dear Lennard,
I’ve heard a lot about there being compatibility between the major brands 11-speed cassettes. I was wondering whether you had found anything similar and [if I] could run a Campy groupset with a Shimano/SRAM cassette, or vice versa?
— Ted

Dear Ted,
Yes, you can, and I’ve been beating the drum about it for well over a year now.

I have 11-speed cogsets from SRAM, Shimano, and Campagnolo spread randomly around my road and cyclocross bikes, which also vary between SRAM, Shimano, and Campagnolo, and the cogsets all shift well on any of the drivetrains without even requiring readjustment of the derailleur after a wheel change.
― Lennard

Feedback on preventing cleat slippage on the shoe

Dear Lennard,
For years, I had the same problem as the letter writer, but with Sidi Genius shoes and Shimano road cleats (size 51 shoes coupled with your 190mm cranks). I permanently solved the problem by cutting out little shims to fit between the cleats and the shoes, out of flat rubber grippers that usually come two for a dollar at any grocery store (the ones for getting lids off of jars). Just put the cleat on the gripper, use a Sharpie to outline the three holes and the outside, and cut out with scissors and then install under the cleat. I’ve never had a problem since. Way simpler than glue and sandpaper. The rubber is very thin, so it doesn’t need longer screws — and it provides more than enough “stick” to keep the cleats from moving.
— John S.

Feedback on cyclocross tubular gluing

Dear Lennard,
This post about gluing ’cross tires came just after I watched an excellent video on the topic posted by a likely friend of yours, Michael Robson.

There is a bit of promotion in there with the Butter Red Tape, but [it’s] an effective video nonetheless. You may want to consider posting it along with your column.
— John M.

Dear John,
Here it is! Yes, Michael is a good friend, and he does have a good gluing video that I’m linking to just in time for last-minute glue jobs before cyclocross nationals. Thanks, Michael!
― Lennard

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The best new tool of 2014 http://velonews.competitor.com/2014/12/bikes-and-tech/best-new-tool-2014_357057 http://velonews.competitor.com/2014/12/bikes-and-tech/best-new-tool-2014_357057#comments Wed, 31 Dec 2014 22:21:42 +0000 http://velonews.competitor.com/?p=357057

Park Tool's IR-1 Internal Cable Routing Kit is Lennard Zinn's favorite new tool of the year. Photo: Lennard Zinn | VeloNews.com

Lennard Zinn describes his favorite new bike tool from 2014, a clever solution that saves time and frustration, without costing a fortune

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Park Tool's IR-1 Internal Cable Routing Kit is Lennard Zinn's favorite new tool of the year. Photo: Lennard Zinn | VeloNews.com

I love nice bicycle tools. However, in many cases, the price is high for well-made tools that perform a complex task cleanly, easily, and quickly. But every now and then, a tool comes along that is such an elegant solution to a problem that it not only saves time, effort, aggravation, and knuckle skin, but it also is inexpensive.

Park Tool’s IR-1 Internal Cable Routing Kit falls into this category. It makes the otherwise tedious task of internally routing electronic-shift wires, brake cables, shift cables, cable housing, or hydraulic hose through a frame into a smooth, clean, and elegant one without resorting to aimless fishing or to jury-rigged bent wires, tape, and the like. It chops at least half of the time off of routing electronic-shift wires, and, depending on the frame, it can also greatly speed up internally routing cables, housing, and hydraulic hose.

The basic concept of the IR-1 tool is to fish cable, cable housing, hydraulic hose, or electronic wire through a frame by attaching it to a thin cable with a magnet on the end and dragging it through with another magnet.

How to use the tool:

1. Attach the IR-1 “lead wire” to the cable, hose, housing, or electronic wire you intend to pass through the frame. The “lead wire” is either the one with a hollow rubber tubing end on it, or the one with a metal, tapered threaded barb on it (in either case, there is a cylindrical magnet on its opposite end). If you are routing electronic wire or standard cables, use the lead wire with the hollow rubber tubing end on it, which you use to grab either the connector on the end of the electronic wire or the head of the standard brake or shift cable. If you are routing housing or hydraulic hose, screw the threaded barb of the other lead wire into the end of the housing or hose until it holds it securely.

2. Push the lead wire’s magnet in through a hole in the frame and feed it down through the frame tube(s) and into the bottom bracket shell. If need be, pull the lead wire’s magnet through the frame by means of another, hand-held magnet running along the outside of the frame.

3. Into the hole in the frame out of which you want that cable, hose, or electronic wire to emerge, push in the magnet end of the cable that has a cylindrical magnet on its end and nothing on the other end (I’ll call it the “fishing wire”).

4. Guide that magnet into the bottom bracket shell as well, again using the hand-held magnet on the outside of the frame when necessary to drag the magnet on the end of the fishing wire through tough spots inside the frame.

5. Connect the two magnets of the lead wire and fishing wire to each other inside of the bottom bracket shell.

6. Pull on the opposite end of the fishing wire to drag the lead wire, and, ultimately, the end of the cable, hose, or electronic wire out of the frame hole. The magnets on the ends of the wires are powerful enough to hold the lead wire and fishing wire together even when pulling through pretty tight spots.

Voilá! With little muss and fuss, you now have routed your cable, hose, housing, or electronic wire through the frame.

Giving credit where credit is due, Campagnolo pioneered this concept with its $70 EPS Cable Guide Magnet kit. I explain how to use it in “Zinn & the Art of Road Bike Maintenance, 4th Ed.,” and a couple of years ago, I posted a few photos of it here in this FAQ. Thing is, Campagnolo only made its kit to work with EPS wires; its single lead wire has an EPS connector on the end to clip to the end of an EPS wire. Campy also used stainless steel cable for the fishing wire; stainless steel is not magnetic, so the hand-held magnet can only pull on the magnet end of it.

Park, on the other hand, made its IR-1 Internal Cable Routing Kit universal for both Campagnolo EPS and Shimano Di2, as well as for hydraulic hoses and for standard shift cables, brake cables, and cable housing. Like Campagnolo, its “fishing wire” is just a standard shift cable whose head is attached to a cylindrical magnet with shrink tubing. Unlike Campagnolo, however, Park’s fishing wire is magnetic steel and allows the user to also drag the tip of the fishing wire along inside the frame using the hand-held magnet; this is useful for frames where the cable-entry hole is too small for either the magnet end of the fishing wire or for either end of the lead wire. Then, if you’re trying to get housing through the frame through small holes, you can slide the housing onto the cable.

Also in contrast to Campagnolo, Park offers two different “lead wires,” and neither of them is specific to a brand or model. Park’s lead wire for guiding electronic wires is also usable for guiding standard internal brake and shift cables. It has a flexible rubber hollow receiver on the end that will stretch over either a Di2 or EPS electronic connector, or over the head of a shift or brake cable. Park’s other lead wire has a conical threaded metal barbed end that can be screwed into the end of either cable housing or hydraulic hose, allowing the user to easily pull either of those through a frame.

Park’s additional magnet for pulling an internal magnet along inside of the frame is analogous to Campagnolo’s, but Park’s is built into a nice anodized-aluminum handle.

The universality of Park’s $50 IR-1 kit makes it useful and accessible for anyone with internal cables, hoses, or electronic wires. It truly is the best new tool I’ve used in 2014, and it is also among the least expensive!

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Tech FAQ: Mixing Shimano road, MTB Di2 derailleurs http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/tech-faq-mixing-shimano-road-mtb-derailleurs_356751 http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/tech-faq-mixing-shimano-road-mtb-derailleurs_356751#comments Wed, 24 Dec 2014 14:37:40 +0000 http://velonews.competitor.com/?p=356751

Compatibility problems exist between Shimano's road and mountain electronic groups. Photo: Lennard Zinn | VeloNews.com

Lennard Zinn addresses questions pertaining to interchanging various Shimano drivetrain parts

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Compatibility problems exist between Shimano's road and mountain electronic groups. Photo: Lennard Zinn | VeloNews.com

Dear Lennard,
I read your post earlier this year that the XTR Di2 rear derailleur would work with the Di2 front shifters. I just got the XTR rear mech [derailleur], and it won’t work. I have the new Ultegra 6870 setup (2 of them on 2 different road bikes).

I called Shimano today and got through to their tech support, and they told me that at present the road shifters are not compatible with the XTR Di2 derailleurs. I asked if they had plans to upgrade the firmware to let it work, given the large number of people who would, like me, want to use a wide rear cassette for some road mountain or tandem bikes. They said, “no current plans.” FYI, when I connect the bike to the Shimano PC interface and set the bike to “MTB,” I can get the rear XTR derailleur to be recognized along with the battery and switch box; but it says, “remove road shifters and derailleurs.” Similarly, if I designate the bike as a “road” version, it says, “remove MTB rear derailleur.” When the XTR rear mech is connected along with the regular Ultegra front derailleur and shifters, not only will the rear derailleur not work, but the front derailleur won’t work either.

Do you know a workaround that caused you to make the comment in Velo about compatibility?
— Mark

Dear Mark,
Thanks for being the guinea pig for us all on this. Your experience came as a surprise to me, since I had understood from Shimano at the XTR Di2 introduction that there would be complete compatibility between road and mountain Di2. I have yet to get any XTR Di2 myself, and I do plan to try various combinations with road components when I do.

Electronic components have doubled the possibilities for incompatibility. They have brought us not only incompatibilities based on intended use similar to those of mechanical systems (yours falls in this category), but also incompatibilities that we constantly run up against with our computers due to software revisions. When it comes to Di2, we can lose compatibility with components that had been happily working together by simply performing a software update.

No, I do not know a workaround other than to run it without a front derailleur. That’s probably not what you want to do, given your desire to greatly widen your gear range.

I got some answers from Shimano about this, and I now know that you cannot mix any road FD (front derailleur) with an XTR Di2 (11-speed) rear derailleur (RD-M9050); it won’t work with any Di2 shifter, road or MTB. This is similar to incompatibility to trying to mix numbers of speeds, as it won’t work to mix any Di2 FD/RD road derailleurs that aren’t both 10- or 11-speed. (Actually, it may work to mix, for instance, an Ultegra FD-6770 front derailleur with an RD-6870 rear derailleur until you update the battery software. After that, it will never work again.)

You can run a full XTR Di2 drivetrain with your Di2 road levers (you could use any Di2 ST or SW Di2 switch, like climbing, sprint, or TT switches with it). That would be analogous to mixing 10-speed ST-6770 (Ultegra Di2 shifters) with 11-speed RD/FD, or 11-speed ST-6870 (Ultegra Di2) or ST-9070 (Dura-Ace Di2) with 10-speed FD/RD-6770 (original Ultegra Di2). Both of these road combinations do work.

You could also run a 1×11 system with that XTR RD. The FD is not needed to make the system work. You could use any ST or SW with it.
― Lennard

Mixing 9-, 10-speed components

Dear Lennard,
I have a Shimano 9-speed triple setup on my hill road bike using an XTR RD and 11/34 XTR cassette. I would like to switch to Shimano 6603 shifters, with a 105 triple FD 10-speed. Will the 6603 shifters function with a 9-speed RD and a XTR 10-speed cassette 11/34? Or will I need a long-cage road RD like RD 6700?
— Dave

Dear Dave,
Yes, you can use a 9-speed XTR rear derailleur with 10-speed Shimano shifters, chain and cassette.
― Lennard

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Top 14 stories of 2014: Felt factory tour http://velonews.competitor.com/2014/12/bikes-and-tech/top-14-stories-2014-felt-factory-tour_355029 http://velonews.competitor.com/2014/12/bikes-and-tech/top-14-stories-2014-felt-factory-tour_355029#comments Tue, 23 Dec 2014 13:30:05 +0000 http://velonews.competitor.com/?p=355029

A TeXtreme fabric top layer on a Felt Virtue FRD mountain bike frame not only gives a nice checkerboard appearance, but it resists stresses from all angles. It also sandwiches layers of unidirectional fabric between itself and a similar TexTreme sheet to form the bottom layer that prevents unidirectional fibers from imploding inward in the case of a hard impact. Photo: Lennard Zinn | VeloNews.com

Lennard Zinn goes into detail about the California company's six most notable designs and manufacturing processes

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A TeXtreme fabric top layer on a Felt Virtue FRD mountain bike frame not only gives a nice checkerboard appearance, but it resists stresses from all angles. It also sandwiches layers of unidirectional fabric between itself and a similar TexTreme sheet to form the bottom layer that prevents unidirectional fibers from imploding inward in the case of a hard impact. Photo: Lennard Zinn | VeloNews.com

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Technical FAQ: Tubular gluing and taping, cold-weather braking and tire changing http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/technical-faq-tubular-gluing-taping-cold-weather-braking-tire-changing_356125 http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/technical-faq-tubular-gluing-taping-cold-weather-braking-tire-changing_356125#comments Tue, 16 Dec 2014 18:59:43 +0000 http://velonews.competitor.com/?p=356125

Lennard Zinn recommends one layer of Belgian tape and four layers of glue when mounting tubular tires. Photo: Lennard Zinn | VeloNews.com

Zinn answers questions about 'cross tubular glue/tape combos, the right brakes for cold-weather riding, and how to stop a slipping cleat

The post Technical FAQ: Tubular gluing and taping, cold-weather braking and tire changing appeared first on VeloNews.com.

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Lennard Zinn recommends one layer of Belgian tape and four layers of glue when mounting tubular tires. Photo: Lennard Zinn | VeloNews.com

Dear Lennard,
My shop recently glued up a set of Clement MXPs for me using Tufo Tape and layers of glue. I’ve since been doing some research and found that there’s a bunch of negative reviews about this method, but most seem to reference Tufo Extreme and Tufo Regular tape. It seems Tufo has updated their tape since most of these reviews with just a general Road tape option. I’ve found one review on this presumed newer tape that’s favorable but no other information.

Have you heard any feedback on Tufo Tape and CX recently?
— Logan

Dear Logan,
I checked with Tufo, and the response I received was, “no changes, one tape for road, one tape for MTB, no tape for CX.”

I have tried what your shop did, and I can say that Tufo road tape didn’t work adequately for that application. I used a combination of both Tufo Extreme and Tufo standard road tape and glue about five years ago on a number of cyclocross wheels, and all of them either rolled off in races or would have if I hadn’t re-glued them. I did roll three of them in races before I had the sense to pull them all off. The Tufo tape delaminated (it’s a multi-layer tape), and the tires came off incredibly easily. It’s possible that the glue caused the tape to delaminate, but I know that adhesion without glue is also insufficient for CX with Tufo road tape. I recommend you have the shop re-glue those tires; at least pull one off to see what the adhesion is like before you attempt racing on the other one.

I’ve also tried a combination of Velox Jantex tubular gluing tape and layers of glue, and that also didn’t keep the tires on. I rolled three of those in races, too, before I had the sense to pull them all off.

I only recommend gluing CX tires with Cyclocrossworld.com’s “Belgian Tape.” Here’s the method, and it also mentions my preliminary experience with Tufo tape and glue in CX; unfortunately, the photos showing the gluing process as well as the delaminated Tufo tape were not archived with the article.
— Lennard

Dear Lennard,
I live in Minneapolis, and with all the new (sort of) road bikes with disc brakes, larger tire clearances and fender mounting, I’m considering a wet/cold weather commuting bike. My question also pertains to fat bikes, which are very common up here.

I’ve looked all over the web, called a few manufacturers, and no one seems to have good information about cold weather performance of disc brakes, whether operating or storage. I’ve seen mention that mineral oil should be stored at room temperature, but that’s very generic advice, and that DOT fluid will absorb moisture.

What’s best in the cold — mineral oil, DOT fluid, cable, or cable/hydraulic with mineral oil (TRP HY/RD)?
— Greg

Dear Greg,
Since hydraulic disc brakes work so much better than anything else in warm and down to quite cold weather, and since there aren’t too many days each year that the temperatures in Minneapolis get down to -10F or colder, I’d still use hydraulic discs. Given that the viscosity of mineral oil and DOT fluid is about the same to start with, I’m willing to bet that the added sluggishness both of them develop in deep cold will be similar.

Below are some answers from some diehard winter riders.
― Lennard

From an any-weather rider in Winnipeg:
“I like mechanical disks for really cold weather, especially if you store your bike indoors. A warm rim planted into soft snow will instantly render rim brakes useless, as the snow melts onto the rim and freezes again. That said, I rode with rim brakes for years, and got by okay. I recently rode with a guy on expensive hydraulic brakes in minus 25C (-13F). He said they worked, but were a little slow. I would stick with less expensive, more robust cables.”
— Andrew

From a dedicated New Hampshire fat-bike snow rider:
“I really have never had an issue with my hydro discs in the winter, aside from sometimes (and this is only an Avid issue) some howling. That being said, I recently switched to the new SRAM centerline rotors and they are very quiet so far.

I also have always run the organic pads instead of sintered. They wear faster, but have much better performance right out of the box.

I personally love my Avid Trail 9 brakes, but next time around I’ll be switching up to the new SRAM Guide brakes.”
— Kris

Dear Lennard,
I have a question for you about road tubeless tires. I was doing my Milano-Sanremo impression yesterday by riding in snowy weather, when I flatted my rear tire. It’s a Hutchinson Fusion tubeless, on a Bontrager race 29 tubeless wheel, on my CX bike. I went to put a tube in, but spent 30 minutes in the cold just trying to get the tire off with no success. Eventually I had to call a cab before hypothermia set in.

In my warm living room this morning, the tire comes off by hand in 10 seconds. I’m assuming the cold yesterday (~34F) shrunk the bead, locking it in super tight? But that’s not really workable if I can’t change the tire in an emergency. Is there a magical tool I don’t know about for cold weather removal, or do I have to switch to clinchers for the winter?
— Alex

Dear Alex,
I think the answer is that there is no such magical tool. I asked a bunch of tubeless riders, including Stan of Stan’s NoTubes itself, and they all said they hadn’t run into that before. So I don’t imagine a tool exists for something that not many people run into. I can’t personally remember changing a tubeless tire at freezing temperatures.

I’m assuming that you meant “around 34F” (i.e., just above freezing) and not “-34F”, when you wrote “~34F.” But if you actually meant you were trying to change a tire at 34 degrees below zero Fahrenheit, then I think there’s a deeper issue here, in addition to the fact that the sealant would be frozen.

If you ride above the freezing point, and even within a few degrees below it, you’re still less likely to have a flat if you are running tubeless tires with sealant than if you’re running tubes. So I’d still tend to stick to tubeless tires for their reliability and chalk this one up as a one-off that you probably won’t ever have to face again.
― Lennard

Dear Lennard,
I have Shimano shoes with hard/slippery plastic bottoms and Look cleats with hard plastic bottoms. No matter how much I tighten the screws (I am strong) they slip after five or six spin classes.

I have tried Loctite blue and red they still slip out of my desired position. I weight 185lbs and spin pretty hard.
— B.

Dear B.,
Try gluing a piece of sandpaper, rough side out, to the bottom of the cleat; I suggest using contact cement (put it on both surfaces, allow them to dry, then stick them together). Once it’s glued on, trim around the cleat and in the cleat holes with a razor knife. The sandpaper will dig into the hard shoe sole and keep it from slipping.

I also wonder if Park Tool’s SAC-2 SuperGrip Carbon and Alloy Assembly Compound might work. This stuff is amazing at how it makes a carbon seatpost that constantly slipped down become super difficult to pull out of the frame.
― Lennard

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Technical FAQ: Tire sealant questions http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/technical-faq-tire-sealant-questions_355499 http://velonews.competitor.com/2014/12/bikes-and-tech/technical-faq/technical-faq-tire-sealant-questions_355499#comments Tue, 09 Dec 2014 17:45:28 +0000 http://velonews.competitor.com/?p=355499

Nearly all tubeless tires work better with a bit of tire sealant. Lennard Zinn answers questions about how to get the most out of your goop. Photo: Caley Fretz | VeloNews.com

Lennard Zinn answers questions about tire sealant, tubeless tires, and whether or not it's possible to drain sealant from tubes

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Nearly all tubeless tires work better with a bit of tire sealant. Lennard Zinn answers questions about how to get the most out of your goop. Photo: Caley Fretz | VeloNews.com

Dear Lennard,
I have been happily using tubeless road tires for almost a year without a flat. I carry a spare tube along just in case, but I’m not looking forward to wrestling a tight-fitting tubeless tire off and on the rim out on the road in cold weather, should the need ever arise.

I use Stan’s No Tubes sealant. They specifically recommend against using a standard CO2 inflator to re-inflate tires because it will cause their sealant to ball up and be rendered useless. I’m wondering if I can use a Hutchinson Fast’Air Latex Aerosol Inflator out on the road instead. Is it compatible if Stan’s is already in the tire?
— Win

Dear Win,
You generally can’t count on using the same sealant long-term after having inflated it with CO2 or with a sealant-filled inflator. Here are some replies from sealant makers.
― Lennard

From Effetto Mariposa:
“Inflate and repair cartridges commonly contain liquid sealant and propane (or methane-propane mixes), a gas that turns to liquid at lower pressures (5 bar @ 0°C) compared to CO2 (around 35 bar @ 0°C). That’s why inflate and repair cartridges come in aluminum cans and CO2 comes in little steel cylinders; the internal stress the container has to endure is much less for propane. That’s also the reason why you get more inflating power from a small 16g CO2 cartridge than from a big 75ml inflate and repair cartridge, but I digress.

The expansion of a gas is an endothermic reaction (brutally said, it “sucks” heat) and the magnitude of the temperature drop is related to the initial gas pressure; because of its higher cartridge pressure, CO2 will “freeze” a lot more than inflate and repair cartridges like our Espresso.

The reason why latex sealants solidify when using CO2 cartridges is a physical one; it’s the big thermal shock, which often initiates the polymerization of the sealant. To avoid it, it’s normally sufficient to put the valve at 12-o’clock prior to inflation and let the sealant flow down to the 6-o’clock area, so that it won’t be directly hit by the cold gas. Also, reducing the inflation speed (most CO2 adapters allow it these days) will prevent dropping the temperature too much, good for the sealant … and good for your hands, if you’re not wearing gloves.

Inflate and repair cartridges, while sealant-safe from a physical standpoint, are dangerous for the sealant from a chemical standpoint, though. Besides physical shocks (thermal shocks, but also sudden evaporation — as in the case of a puncture), changes in the pH of the sealant can also trigger its polymerization. Using an inflate and repair cartridge, you’re mixing the sealant inside your tires with the sealant inside the cartridge. The mix is stable if both have the same pH (like our Espresso and Caffélatex, which have a similar formula for this very purpose); otherwise, the sealant will normally solidify in a matter of minutes or maximum a few days. This won’t prevent roadside repair, so the cartridge will serve its purpose, but you’d better wash away the sealant mix once at home and restore your liquid sealant of choice, for enduring protection.
— Alberto De Gioannini
Founder, Effetto Mariposa Sagl”

From Stan’s:
“We have not tested the Hutchinson FastAir that contains a liquid sealant. We have used the Propane Big Air and the Big Air works fine with our sealant. CO2 will get you out of the woods, but we found it reduced the life of the sealant.
— Peter Kastner
System Manager
Stan’s NOTUBES”

Also from Stan’s:
“I don’t think the propane will affect the sealant. Either way, he just needs to get home. Once home, he can remove one bead of the tire and inspect his sealant. Tubeless tires are not hard to dismount if you push one bead into the drop channel and remove this bead while leaving the second bead stretched on the tubeless bench. It’s harder to remove the tire once both beads are in the drop channel. But even then, a plastic lever can remove the first bead and the second will push off with your hand.
— Stan Koziatek
Stan’s NOTUBES”

Dear Lennard,
I have read a few columns about sealant, and after an encounter with some glass on a cold, rainy day, I’m keen on trying some. I read one test where the author found certain products can work quite well in latex-tubed clinchers. However I’m a bit concerned about the sealant drying out and either leaving a big clump of cured sealant in my tubes, or simply ceasing to seal any fresh punctures. Orange Seal and Bontrager TLR performed quite well in the test I’m thinking of. Do you have any knowledge about how long the sealant would last in a latex tube with a bit of either of these sealants installed? What does one do to prevent the sealant from drying out, or to rehabilitate a tube with dried out sealant?
— Cornelius

Dear Cornelius,
The sealant will stay liquid for a very long time as long as you keep the valve closed, including during off-season storage where it stays deflated. I have only used Caffelatex in latex tubes (and those are only in tubulars), since that’s the sealant that Dugast recommends for the latex tubes in its tubulars. And the sealant has lasted for a couple of seasons, when I consistently left the valve closed.

You can’t rehabilitate a latex tube with dried-out sealant in it, and removing the sealant is also not practical. I have removed sealant from latex-tube tubulars for the off-season. It is not something I’d repeat again. It required a ridiculous amount of rinsing, inflating, draining, rinsing, etc., and it stressed the valve so much that it ended up that I discovered, at the beginning of the next season, that I had created a leak around the base of the valve stem on a couple of the tubulars. I don’t recommend it.

Sealant removal is only practical with tubeless tires; wiping it out of tubeless clinchers is easy, and you can also suck it out of tubeless tubulars—namely Tufo and Clement (also made by Tufo).
― Lennard

Dear Lennard,
Now that tubeless tires have been around for a number of years I was wondering if there is a definitive maintenance routine that should be followed to insure safety and the flat-free riding that they offer.

Personally I take my tires off once a year, usually during a cold spell-inspired round of bike maintenance. More often than not, I find a small “Stan’s ball,” as I’ve come to call it, of hardened sealant in MTB tires. In road tires there can be a few pellet-size particles. I clean the contact areas of the rims, remount, and replace the sealant. I have been told by a good local mechanic that this is unnecessary and to just add a few ounces of sealant a few times a year. This would seem to make the tire set-up heavier over time and that Stan’s ball would still be inside the tire, hypothetically just getting bigger. As might be expected, searching on the Internet has yielded a wide range of opinions.

Have any recommendations or guidelines been developed by the manufacturers and/or professionals in the business of bicycle maintenance, such as yourself, over the past few years?
— Rick

Dear Rick,
The Stan’s ball appears where air is leaking out of the tire. Presumably those spots in your tire are now sealed, so they won’t tend to get bigger with the addition of more sealant. Once the liquid in the sealant has dried out, there is very little weight to be concerned about, other than large Stan’s balls. While it’s not that big a deal to pop one bead off of your tires and wipe out the old liquid and hardened sealant, your mechanic has a point; just adding a bit more sealant periodically is easier.

I’m much more concerned with leaving a tire deflated and parked for a long time, as the sealant con solidify in a long, solid puddle at the bottom of the tire, thus throwing it out of balance. Peel this out and then add more sealant.
― Lennard

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Resistance is futile: How tire pressure and width affect rolling resistance http://velonews.competitor.com/2014/12/bikes-and-tech/resistance-futile-tire-pressure-width-affect-rolling-resistance_355085 http://velonews.competitor.com/2014/12/bikes-and-tech/resistance-futile-tire-pressure-width-affect-rolling-resistance_355085#comments Fri, 05 Dec 2014 19:25:35 +0000 http://velonews.competitor.com/?p=355085

All else equal, decreasing rolling resistance (rr) increases speed. Shorter curves indicate faster, lower rr tires. The two colors on each curve show rr for each tire at different tire pressures, 84 and 112 psi.

For the November 2012 issue of Velo magazine, Lennard Zinn headed to the laboratory to see how tire pressure and width affect rolling

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All else equal, decreasing rolling resistance (rr) increases speed. Shorter curves indicate faster, lower rr tires. The two colors on each curve show rr for each tire at different tire pressures, 84 and 112 psi.

Editor’s note: This tech article ran in the November 2012 issue of Velo magazine.

Whether on tarmac or singletrack, a tire with lower rolling resistance reduces the power required to move forward while also providing a better quality ride. The tire absorbs small bumps by not transferring them into the bicycle and rider, resulting in a smoother ride, faster speeds, and better cornering. How could you pass that up?

During a February, 2012 visit to Wheel Energy, an independent tire-testing lab in Finland, I was fascinated by the tests the lab was doing for tire brands like Vittoria, Specialized, Bontrager, and many others. As an independent lab, Wheel Energy will not disclose any of the results of a test it has performed for its clients, so the only way to obtain results was to pay for our own test. Many of us at Velo have our own opinions about what contributes to tire rolling resistance and we wanted to see if they held up when the rubber hit the road. Rather than which brand or model is fastest, we were much more interested in how tire width and tire pressure affect rolling resistance.

We sent a Zipp 303 wheel and five pairs of Challenge tires to Wheel Energy. We chose Challenge because the company makes a number of tubulars with similar casings and tread patterns in different tire widths. We tested the following tires:

Forté, 700 X 22mm, diamond tread pattern, 240 grams, 30mm tread width
Forté, 700 X 24mm, diamond tread pattern, 255 grams, 30mm tread width
Strada, 700 X 24mm, herringbone tread pattern, 250 grams, 28mm tread width
Strada, 700 X 25mm, herringbone tread pattern, 260 grams, 29mm tread width
Paris-Roubaix, 700 X 27mm, herringbone tread pattern, 320 grams, 37mm tread width

Editor’s note: Challenge no longer offers some of the tested sizes. The Forté tubular is now only available in 24mm size and 300tpi casing. The Strada tubular is available in the 25mm size with 300tpi casing, but not the 260tpi casing. The Paris-Roubaix tubular tire is now only sold with 300tpi casing, 27mm size. Challenge’s Criterium tubulars were not tested for this article, but they are available in 23mm and 25mm sizes with 320tpi casings or the Seta silk casing.

The test

Wheel Energy warms up each tire for 30 minutes on a drum with a hydraulic load cylinder pushing the tire down against it. Besides getting the tires up to normal operating temperatures, this also serves to remove wax and mold-release lubricants from the tire.

The wheel is then transferred to a much larger, 1,200-millimeter diameter drum, which has bolt-on removable texture plates. To represent a road with cracks or chip seal, we chose a diamond plate on the roller similar to industrial stair treads. Each diamond-shaped bump is about 40mm long, 4mm high, and 3mm wide.

Each tire was run on the drum at 40kph with a 50-kilogram mass pushing down on the Zipp wheel’s axle. Wheel Energy ran two rolling-resistance tests with each tire — at 112 psi and 84 psi.

Once the power stabilizes, software records the power it takes to drive the wheel at that speed on the roller. The higher the power required to drive the wheel, the higher the rolling resistance of the tire.

When asked how he measures the power to drive the wheel, Wheel Energy director Petri Hankiola says, “It is secret information. We used about 1,000 hours to plan this device.” It almost certainly has something to do with measuring the current the motor draws to hold the speed at 40kph.

Results

For rolling resistance coefficient (rr), the tires finished in the same order at both tire pressures, with the 24mm Stradas having the lowest coefficient (i.e., fastest rolling), followed by the 25mm Stradas, the 27mm Paris-Roubaix, the 24mm Forté, and the 22mm Forté.

All of the tires had lower rolling resistance at 112 psi than at 84 psi, with the difference being very slight with the higher-rr tires — the two Fortés — and the difference being greater with all of the herringbone-tread tires, the Stradas and Paris-Roubaix.

Analysis

Based upon experience, especially with cyclocross and mountain bike tires, and from data shared with me by Specialized, Schwalbe, and Vittoria (much of which came from testing done at Wheel Energy), I had expected the wider tires to have lower rolling resistance than the narrower ones. I had also expected the rolling resistance to be less at lower pressure. While at first glance the former seems to be in doubt, a closer look reveals that that assumption is probably sound. The latter was proven not to be true, however.

Width versus rolling resistance

Tire rolling resistance on the road is caused by (1) internal friction and hysteresis (deformation over time) within the tire’s materials, and (2) on rough roads, small bumps lifting the bike and rider slightly (uphill) on each little impact.

By definition, wider tires will have shorter contact patches and, hence, less tire deflection; if the tire pressure is the same, the area of the contact patch must be the same to support the same load. The shorter the contact patch, the lower the vertical depth of tire deflection; the internal friction and hysteresis within the tire’s materials is lower.

If a wider tire is made of the same materials in the same thickness as a narrower one, it will roll faster, because (1) the internal friction and hysteresis within the tire’s materials will be lower, and (2) because the surface imperfections in the road will be absorbed into the tire more easily (since it has more deflection available), thus lifting the bike and rider slightly less with each little impact.

Thread count and thread pattern

Clearly on the Forté tires, the wider tire has lower rr. These two tires have identical construction and tread; they differ in casing diameter, which is a clear demonstration that wider is faster. The casing is 300 threads per inch (TPI) of Super Poly threads, the same thread material (but not the same thread thickness) used in all five pairs of tires tested.

The thinner the threads, the higher the thread count in TPI, which is simply the number of thread wraps lined up next to each other in one inch of the casing fabric. On tires like this, the casing is made by wrapping thread around a long, spinning spool and then wetting it with liquid latex. Then it is cut on the bias and folded over to make a two-ply casing with the threads in each ply crossing each other at right angles.

Generally, the higher the thread count, the more supple the casing. That’s because the threads are thinner in high thread-count tires, making the casing thinner, lighter, and more flexible. Also, when the tire encounters an object, thinner, lower-mass threads will be able to move and absorb the object into the casing more quickly than will thicker threads.

The only other tire in the test with a 300 TPI casing is the 24mm Strada, the tire that came out with the lowest rr of any of the tires. The wider (25mm) Strada and the Paris-Roubaix (27mm) both have thicker, and hence stiffer, 260 TPI casings than the other three tire models. Otherwise, there is no difference between the black casing of the Forté and the tan casing of the Strada and Paris-Roubaix. “It is just a few drops of yellow or black color in the latex,” according to Challenge Tech president Alex Brauns.

The herringbone tread on the Strada, however, is noticeably more supple than the Forté tread (a “diamond with S-shape sides” pattern, as Challenge calls it). The herringbone tread (one might also call it a file pattern) on the Strada and the Paris-Roubaix lies flat when deflated, whereas the diamond casing on the Forté seems much stiffer and holds its curved shape when deflated.

The rubber compound in the tread of the Forté and Strada is the same, but Brauns says that the “Paris-Roubaix has a slightly harder compound to increase protection from cuts and stones. The difference is small — from 50 to 55 (durometer) — to avoid losing grip on wet surfaces, but enough to give a more resistant compound.” The tread thickness on the Forté is the same as the Strada, but the Paris-Roubaix has thicker tread and its anti-puncture protection belt is wider.

Since the 25mm Strada has a stiffer casing, a wider tread, and a wider puncture-protection belt than the 24mm Strada, it is not surprising that it has higher rr than does the narrower Strada. And while the 27mm Paris-Roubaix has the same casing fabric as the 25mm Strada, it has a harder tread compound and a wider puncture-protection belt than the Strada, so it is also not surprising that its rr is a bit higher. Despite these extra stiffening measures in them, the 25mm Strada and the 27mm Paris-Roubaix both have lower rr than either of the narrower Forté tires, which also have suppler casings. So, I think that the contention that a wider tire rolls faster, all other things remaining equal, remains intact.

Inflation pressure versus rolling resistance

Lower tire pressure means fewer pounds of pressure on each square inch of the tire. Since the tire supports the same load at lower pressure, the contact patch will be larger. For example, Wheel Energy measured the footprint area of a 700 X 23mm tire inflated to 112 psi with 50kg of weight on it to be 75mm long and 15mm wide. The footprint of the same tire with the same weight on it, but inflated to 84 psi, became 82mm long and 14mm wide. The longer contact patch means that the tire deflection will be deeper, resulting in more internal friction and hysteresis within the tire’s layers. That makes the case that higher pressure reduces rolling resistance.

On rough surfaces, however, a tire at lower pressure is able to absorb more of the bumps than a tire at higher pressure, with less deflection of the bike and its rider. This is the same “sprung vs. un-sprung weight” argument that demonstrates why suspension makes a bicycle faster on rough terrain — it takes less energy to keep the bike rolling if only a small amount of weight is lifted (like a small section of the tire) than if the entire bike and rider is lifted by the bump.

If the bike were rolling on smooth glass, it’s clear that higher pressure would be faster. The question is, what is the ideal pressure for the surface you’ll be riding on?

For mountain bikes and cyclocross bikes, this is a lot more clear and shows why top riders tend to run quite low tire pressures on rough courses or where traction on sidehills is needed. On the road, there will be a point with every surface where, above a certain pressure, rolling resistance will increase.

Interestingly, the tires with the highest rolling resistance, the two Fortés, have almost no difference in rolling resistance at 84 psi versus 112 psi. The fastest rolling tire, the 300 TPI Strada 24mm and the widest tire, the 27mm Paris-Roubaix, had the biggest increase in rolling resistance (1.6 Watts) when dropping pressure from 112 psi to 84 psi. This indicates that the more supple tires (whether due to more supple materials or to more width) have the biggest change in shape with reduction in pressure and thus the greatest amount of corresponding internal friction and hysteresis due to the materials in the tire layers moving around more.

Editor’s pick

Clearly, the fastest tire here is the 300 TPI 700 X 24mm Challenge Strada. That’s the tire we would choose, even though it weighs more than the 22mm Forté.

We would also pick a wider tire when presented with two tires that are otherwise identical.

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Lennard Zinn diary: A personal rememberence of Steve Hed http://velonews.competitor.com/2014/12/news/remembering-steve-hed_354791 http://velonews.competitor.com/2014/12/news/remembering-steve-hed_354791#comments Tue, 02 Dec 2014 15:33:17 +0000 http://velonews.competitor.com/?p=354791

Lennard Zinn takes notes while talking with Steve Hed. Photo: Tim Mulrooney

Zinn remembers the life and work of Steve Hed, a passionate inventor who was generous in many ways, and a pillar of the bike industry

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Lennard Zinn takes notes while talking with Steve Hed. Photo: Tim Mulrooney

Last week, we lost Steve Hed, one of cycling’s greatest innovators. I lost a good friend whose constant, selfless generosity I could never reciprocate. And perhaps most shocking is that a man my age, with seemingly many productive years ahead of him and with so much to live for, could just walk out of the door of the business he had built over three decades, fall, and never wake up. It leaves such a sudden and gaping hole — in his family, in the cycling community, and in the huge number of friendships he forged over the years through his caring ways.

I feel fortunate to have been friends with Steve Hed for almost 30 years. During that time, he was very generous with his time and expertise with me, and I know I was merely one of thousands that he assisted this way. There are endless stories from triathletes and bike racers of the selfless financial and material support and unwavering loyalty he granted them. On a totally different level, he was also generous with his knowledge. He had a passion for learning new things and willingly dropped everything to pursue a new idea. He never worried about how much it would disrupt his life or what resources he would risk to pursue an idea, and I believe this set him apart from most of us.

Hed pioneered wind tunnel research on bicycles. His early interest in model airplanes led him to the tunnel, as well as his gravitation toward people with new and interesting bike ideas — in this case, to Boone Lennon and the aero handlebar he had patented. Lennon had worked in wind tunnels as a US Ski Team coach, and Hed plunged right in and paid the hourly wind tunnel fee (which to me, at the time, sounded like a king’s ransom) from the funds of his fledgling wheel company.

Hed invited me to the Texas A&M wind tunnel for the first time in early 1989 and again after Greg LeMond’s dramatic final-stage Tour de France victory that July, and it had a profound influence on me. I collected material for lots of VeloNews articles and forged many important relationships on a number of trips to that tunnel with him. I got to know Greg LeMond better, met a youthful Lance Armstrong at the dawn of his cycling career, and also met triathletes Scott Molina, Scott Tinley, and Mark Allen. Giro founder Jim Gentes, and aerodynamicists John Cobb and Chester Kyle were there as well. Out of our shared tunnel work, Hed, Lennon, and I developed a number of projects together.

Hed loved investigating new ideas, and he was often more committed to my ideas than I was, which inspired me to have more confidence in pursuing some of them. When I didn’t have the wherewithal to prototype an idea I had, he would jump in, make it and would not accept any money for having done so.

When my maintenance books became popular, Hed told me that I should come up with a line of tools to go along with them. I’m quite sure that if he had been in my shoes, he would have simply started making tools in his little house in White Bear Lake, Minnesota. He did inspire me to work on tool ideas, though, and one of them became a reality (the Pedro’s Vise Whip cog-removal tool, for example).

Speaking of his little house in White Bear Lake, I felt a kinship to him as another guy with a home business. He couldn’t see the point in moving his growing business to a big, commercial space until he absolutely had to. Since his house happened to be in an area zoned both residential and commercial. Why not just keep wedging more into it as the business grew? He and his wife, Anne, eventually moved out of the little house, but it continued to be the home of HED Design for many more years. Watching so much get produced and shipped out of that little house inspired me to do more with my own. The Heds came to mind the first time I visited Ernesto Colnago and saw the way the brothers Colnago had just kept digging out an ever-larger basement connecting their two houses as they needed more space for their business. And, like Hed, they were making cutting-edge carbon-fiber products out of a cramped basement.

The fate of many pioneers is to end up trampled by those following the trail they blazed, but not Hed. Indeed, many wheel companies imitated Hed’s designs, and Hed’s major competitor even brazenly obtained the right to copy his work outright by convincing HED Design’s cofounder to license a HED patent on wheel shape behind Steve’s back. Nonetheless, Hed still kept growing his company through innovation as well as shrewd marketing, production, investment, and wise spending. Yes, he invested more in top athletes than the size of his company would seem to warrant, but he also kept expenses low. Where others would have spent a lot on a big commercial space, he saved hundreds of thousands of dollars by staying in the little house in White Bear Lake until the seams literally burst. And he didn’t overdo it with tooling. Where others in his position would have poured millions of dollars into CNC machines and heavy molds, Hed quickly whipped out lots of prototypes and even final products with woodworking tools and wooden molds.

Of his many wonderful characteristics, I particularly admired and greatly aspired to Hed’s innocent approach to tackling a problem. When pursuing a new idea, he came up with elegant solutions others didn’t see because they’d been blinded by the knowledge of how it has always been done before.

As a single example, consider the lowly valve extender. While Hed’s invention of the deep-section carbon aero wheel (that multiplied the size of the world bicycle wheel market many times over and re-invigorated tubular tire manufacturing) may seem obvious, in the early 1990s, nobody else had yet combined the carbon-composite technology Hed and others were using to make disc wheels with the tension-spoke technology of standard bicycle wheels. There were many small hurdles to overcome to make that big leap, like: 1.) How do you make the rim hollow and light when you can’t manufacture each half separately like a disc wheel? 2.) How do you anchor the spoke nipples without a metal rim spoke bed? 3.) How do you even conceive of a wheel like that when it looks so different, bulbous and unorthodox? 4.) Finally, how do you get air into the tire through that deep rim?

In his usual, enthusiastic way, Hed had made this first super-deep rim and had spoked it up onto a front hub. He was pretty sure it would be fast, and we were at the Texas A&M wind tunnel to test it. Rather than having a detail like inflating the tire stop him — or even slow him down into a distraction like putting a big hole in the rim sidewall to get at the short, little Presta valve, he just mounted an already-inflated tubular tire onto the wheel. When the many wide-eyed onlookers blubbered about getting at the valve, he rolled his eyes and pulled out a chopped-off drinking straw. It would not have occurred to just anyone to run a Presta valve with the nut unscrewed and to stick a straw into the rim and over the valve to pump it with.

In addition to big advances like carbon-spoked wheels and wind tunnel testing, we have Hed to thank for simple little things like valve extenders, inner tubes available in a wide array of valve lengths, and a renaissance in tubular tire manufacturing.

Steve Hed was brilliant and generous, and he was so unassuming that it was easy to forget he had great business instincts, too. His ideas really worked, and he just rolled up his sleeves and made them a reality.

I cannot imagine how much your family will miss you, Steve. I know that the entire bicycle industry will miss you. Rest in peace, dear friend.

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Tech FAQ: Cold tires and brakes http://velonews.competitor.com/2014/11/bikes-and-tech/technical-faq/tech-faq-cold-tires-brakes_354316 http://velonews.competitor.com/2014/11/bikes-and-tech/technical-faq/tech-faq-cold-tires-brakes_354316#comments Tue, 25 Nov 2014 21:14:59 +0000 http://velonews.competitor.com/?p=354316

Andrew Isaacs, a reader in Winnipeg, Manitoba, has some advice for riding in sub-zero temperatures. Photo: Andrew Isaacs

With winter setting in, Lennard Zinn answers questions about riding in cold, muddy, and sometimes extreme conditions

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Andrew Isaacs, a reader in Winnipeg, Manitoba, has some advice for riding in sub-zero temperatures. Photo: Andrew Isaacs

Dear Lennard,
Minnesota is getting blasted by its first storm of the season, which has me wondering: Are narrower or wider studded tires better for riding on icy roads? Wider mountain bike tires have a wider contact patch with perhaps more studs in play, but narrower tires have a higher pressure contact patch and maybe more traction, right?

Which size tire do you think works best?
— Charlie

Dear Charlie,
I am deferring to a buddy of mine who rides studs a lot. Since I work out of my house and don’t need to commute, I can pick my cold-weather riding. I love riding in snow, but I avoid ice and don’t ride with studs. But my friend Mike Prendergast, who did this awesome film about riding all winter long, is an expert on riding studded tires. Mike has this to say:

Winter cyclists encounter a mix of fresh snow, compacted snow, and ice. And some will face rutted snow or ice on roads and trails.

Studded bicycle tires are fairly wide with the narrowest being around 35mm. In my winter riding experience, the width of the tire is more critical for riding in snow while the number and placement of studs is important for ice. For ice without ruts, studded tires of any width have superior traction.

If you are riding on plowed roads and paths, a tire with around 100-120 carbide studs will be a good choice. If you ride on dirt roads or paths that may or may not get plowed, then a tire with around 240 carbide studs will be needed to handle ruts. Ruts will form after trail- and road-user tracks refreeze.

You will only need wider tires to stay on top of deep snow. As long as the snow depth is not more than a few inches, even a fairly narrow studded tire will drive down and get good traction.
— Mike Prendergast
ChainRing Films

Enjoy riding on the ice, Charlie!
— Lennard

Dear Lennard,
I have begun using tubeless tires on my mountain bike in the past year.

With the colder weather, I am wondering what happens to the tire sealant in the cold. Do tubeless tires work just as well when the temperatures get below freezing? Can I expect lumps of hard stuff rattling around in my tires if I hit the trails when the thermometer is in the 20s?
— Bruce

Dear Bruce,
Tubeless sealant is water-based and will freeze. If your bike overnights in a warm house, and the trails start from your house, performance will be okay for awhile. And in that case, any liquid sealant will have been distributed around throughout the tire before it freezes, so you won’t have chunks rattling around.

But if you drive to the trailhead or store your bike in the cold, you could get frozen chunks rattling around in them, because liquid sealant will have pooled up at the bottom and then frozen. (Orange Seal makes a tire sealant it claims is good in temperatures as cold as “negative teens” -Ed.)

Either way, the combination of frozen sealant, reduced tire pressure, and the tire being stiffer due to the cold makes the sealing of your tires more tenuous and negatively affects its ability to absorb side impacts without dislodging the bead.

Due to reduced speeds in the cold, stiffer, cold tires, and fewer thorns, dangers of pinch flats and punctures are reduced anyway, so there’s less of a downside to using inner tubes.
— Lennard

Dear Lennard,
After watching the near implosion of disc brakes in cyclocross from the seemingly instant and complete wear at Nationals not long ago I was nervous about discs in cyclocross.

I now have a disc bike and have purchased, but not installed, some sintered pads for wet conditions.

It isn’t yet wet and I have some questions. Should I install them now or wait for the conditions to warrant the change?

I followed everyone’s advice and “broke in” my original discs and pads with a few dozen hard stops from full speed. Do I repeat this with new pads or just when I change the discs?
— Davo

Dear Davo,
Yes, in the case of thin mud, sintered pads are better. If you do anticipate thin mud for an upcoming race, you might as well change to sintered pads ahead of time. It’s much less fun to change pads in a rush outdoors in cold weather before a race, and you ought to get used to the feel of braking with them in dry conditions, because many times it will turn out dry when you prepare for mud anyway. You don’t need to replace the rotors; you can just break in the sintered pads on the same rotors (and yes, follow the same break-in procedure).

That said, having a set of wheels with mud tires that have solid rotors on them could eliminate pre-race stress. Solid rotors will make way more difference than the sintered vs. organic pads would have anyway. And if you can also switch to the sintered pads in advance, you will have the ultimate setup for thin mud. If the mud turns thick, you won’t need the solid rotors or sintered pads, but there is little downside to having them.
— Lennard

Dear Lennard,
I recently bought a set of black brake pads from eBay for my carbon clincher wheels. Since I’ve installed them, they been leaving white powdery residue on the brake tracks. I’m able to clean them up pretty easily by wiping it off after my ride. I’ve logged about 80 miles on these pads. These are my third set since purchasing the wheels. I don’t recall the first two sets leaving any powdery residue.

If I was mistakenly sold brake pads for alloy wheels, what symptoms will I encounter? Are there any noticeable differences between the pads, such as thickness or shape? The new pads don’t make any irregular noise in comparison to the previous pads. I’m just little a concerned.
— Dennis

Dear Dennis,
On a hot day with heavy braking on a mountain descent, alloy-rim pads on a carbon rim will tend to melt.

In cooler conditions, they will tend to erode like an eraser rubbed on a piece of paper. It will be powdery. I don’t know about white, though. I would call it more gray from a black pad, but against a black carbon rim, maybe it looks white.
— Lennard

Dear Lennard,
I’m from Winnipeg, and I commute year round. My cutoff is about -25 Celsius (-13F) these days, but I have gone lower in the past, down to -40 (-40F. This is the crossover point, where Celsius and Fahrenheit temperature is equal; I can’t imagine riding at that temperature! -LZ).

A few more things that seem to really slow me down in the cold:
1. Squishy Nokian winter rubber is slow.
2. The grease in my hubs and bottom bracket turns into sludge in the cold, as well as the oil on my chain. Sometimes it feels like the wheels barely turn.
3. Riding on snow is like riding on sand. I try to ride on ice or hardpack as much as possible, but it obviously makes a huge difference. As soon as you hit the snow, you also pick up rotating mass in your wheels. (See post-wipeout pic above).
4. The clothing surface area is probably at least double, and as you point out this is really critical. The wind also contains a lot more power due to increased density, and any kind of headwind is killer.
5. I tend to disagree with the “your body slows down” arguments, since regardless of temperature, I’m normally toasty warm a few minutes into the ride. A light fleece and a good shell over your whole body is enough, as long as you take care of covering your face and eyes. Wind chill is not as big a deal as it seems.
— Andrew

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Gallery: Retro gear found at 2014 trade shows http://velonews.competitor.com/2014/11/gallery/gallery-retro-gear-found-2014-trade-shows_353411 http://velonews.competitor.com/2014/11/gallery/gallery-retro-gear-found-2014-trade-shows_353411#comments Tue, 18 Nov 2014 18:33:06 +0000 http://velonews.competitor.com/?p=353411

Lennard Zinn shows us some cycling gear of the past — or, in some cases, replicas of classic items and bikes

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This is my last post from the 2014 bike shows, and this one is as much about going backward as it is about going forward.

As long as there have been bicycles, there have probably been riders yearning for bicycles and accessories of the old days. It’s hard to say what came first, the chicken or the egg, but there is an increasing interest in retro bike equipment coinciding with the rise of retro cycling events like L’Eroica in Tuscany, La Storica in Liguria, La Mitica in Piedmont, and numerous similar events in Italy and other countries.

Antiques and reproductions of equipment from days of yore are two expressions of the retro yearning, and retro products made with modern materials and technology represent another expression of it.

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Gallery: 2015 wheels from Reynolds, DT, Kappius, FSA, Ursus, and Miche http://velonews.competitor.com/2014/11/gallery/gallery-2015-wheels-reynolds-dt-kappius-fsa-ursus-miche_352702 http://velonews.competitor.com/2014/11/gallery/gallery-2015-wheels-reynolds-dt-kappius-fsa-ursus-miche_352702#comments Tue, 11 Nov 2014 21:05:08 +0000 http://velonews.competitor.com/?p=352702

Looking to upgrade wheels for the coming season? Lennard Zinn has the low-down on new 2015 models for road, mountain bike, and more

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Gallery: Aftermarket cranks, chainrings, and bottom brackets http://velonews.competitor.com/2014/11/gallery/gallery-aftermarket-cranks-chainrings-and-bottom-brackets_352016 http://velonews.competitor.com/2014/11/gallery/gallery-aftermarket-cranks-chainrings-and-bottom-brackets_352016#comments Tue, 04 Nov 2014 18:00:42 +0000 http://velonews.competitor.com/?p=352016

Familiarize yourself with some of the aftermarket options for drivetrain parts

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Gallery: Bamboo bikes, innovative tools, and more http://velonews.competitor.com/2014/10/gallery/gallery-bamboo-bikes-innovative-tools-and-more_350726 http://velonews.competitor.com/2014/10/gallery/gallery-bamboo-bikes-innovative-tools-and-more_350726#comments Tue, 28 Oct 2014 20:16:45 +0000 http://velonews.competitor.com/?p=350726

Lennard Zinn shows us a few more things that caught his eye at some recent bike shows

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Gallery: Power unit roundup from Interbike http://velonews.competitor.com/2014/10/gallery/gallery-power-unit-roundup-from-interbike_350055 http://velonews.competitor.com/2014/10/gallery/gallery-power-unit-roundup-from-interbike_350055#comments Tue, 21 Oct 2014 15:26:30 +0000 http://velonews.competitor.com/?p=350055

Lennard Zinn checks out a few power units on display at the annual trade show

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Gallery: New pumps at Interbike http://velonews.competitor.com/2014/10/gallery/gallery-new-pumps-at-interbike_349432 http://velonews.competitor.com/2014/10/gallery/gallery-new-pumps-at-interbike_349432#comments Wed, 15 Oct 2014 12:49:18 +0000 http://velonews.competitor.com/?p=349432

Lennard Zinn highlights some of the latest and greatest bicycle pumps on the market

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When anticipating what the biggest tech advances will be for the coming model year, one doesn’t tend to think of bicycle pumps making that list, much less topping it. But there’s also never been a pump that won Interbike’s Best in Show Road/Cross award before, and the new Silca pump did exactly that this year. One thing is for sure; 2015 will bring us some of the nicest pumps ever made. Here are a number of new pumps that definitely do not suck; they blow!

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Gallery: Sleek Italian bikes at ExpoBici http://velonews.competitor.com/2014/10/gallery/gallery-sleek-italian-bikes-at-expobici_348683 http://velonews.competitor.com/2014/10/gallery/gallery-sleek-italian-bikes-at-expobici_348683#comments Tue, 07 Oct 2014 14:19:50 +0000 http://velonews.competitor.com/?p=348683

Lennard Zinn gets up close and personal with some fine Italian craftsmanship at ExpoBici

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Expobici Gallery: Italian bikes and smoke http://velonews.competitor.com/2014/09/gallery/expobici-gallery-italian-bikes-smoke_347930 http://velonews.competitor.com/2014/09/gallery/expobici-gallery-italian-bikes-smoke_347930#comments Tue, 30 Sep 2014 21:22:46 +0000 http://velonews.competitor.com/?p=347930

Lennard Zinn finds handbuilt frames aplenty in Italy in the closing days of Expobici

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