Further Thoughts on Brakes

My recent post on barrel adjusters received some terrific and thoughtful responses. I also received a couple of e-mail responses that indicate some riders really give brake set-up some thought. Each considered response let me know that I’ve got brothers out there for whom bike set-up is nothing to be left to chance—or a mechanic who doesn’t know your style of riding.

At some point, the alternate views on how to adjust brakes intersected with my memory of some photos I shot last summer as I was inspecting my bike at the end of the Route des Grandes Alpes. My point with this post isn’t, ultimately, to refute other views, but to give you another point to consider as you assemble a bike.

The image above might not make much sense on first glance. After all, it’s from the back of a fork and you really can’t see how the Red calipers are set up. So why is it here? Same reason the following photo is.

If you look closely, you can see scoring on the inside of the fork blades. When I first saw this it didn’t immediately make sense. Then I clamped the front wheel back in the dropouts and realized what I was seeing. The scoring was caused by the edge of the tire tread where it meets the casing. It resulted from open tubulars I ran, tires where the end of the tread has a squared-off edge.

So how did this happen? Let me begin by saying the blame does not lie with the shuttered Alpha Q fork line. The scoring was caused by low spoke-count front wheels. I’m a fairly predatory descender, though I’ll be the first to admit there are guys who’ll drop me like a high-school girlfriend. Those low spoke-count front wheels flex a bit and under hard cornering the wheels flexed enough that the edge of the tread just rubbed the inside of the fork blades. I took a flashlight and a magnifying glass to the marks just to check if there was damage to the carbon fiber. So far, the scoring has yet to penetrate below the clear coat.

What does this have to do with brake set up? Lots, in fact. If you run your brakes really close to the rims, wheel flex can cause the rims to rub the brake pads during either out-of-the-saddle efforts or hard cornering. While I never felt a braking effect in switchbacks, I’ve been able to hear a rim rub a brake and I can’t help but think I’m losing wattage with each pedal stroke. Worse, should I hit any sort of pothole or frost heave or other obstacle that knocks the wheel out of true, I’d need to open up the brake to keep the rim from rubbing. It’s not a huge deal on Shimano or SRAM brakes, but with Campy, opening up the brake lever isn’t something you file under advisable.

If you’re running Ksyriums or some other similar wheel that offers virtually no flex, go ahead and run those brakes close to the rim. Otherwise, consider these images and the possibility that a bit of lever throw might offer some advantages.

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5 comments

  1. John Jorgensen

    Way back I got a case of the big eyes when the rider in front of me hit a pedal and skipped a wheel in a criterium, when he landed his 28 hole rear wheel had a big deflection that within a few revolutions was guided back to line by the brake, amazing to watch. I knew the rider, and approached him after the race, his chainstays were burned by the rear tire, both sides. Made me wary of low spoke count wheels from then on, give me equipment that will get me to the finish, and the tires be tubulars.

  2. Eric

    Good points Padraig. Since I was the one on the other post to comment that I like running the calipers tight, I will acknowledge that in my comments there, I never mentioned less stiff wheels. I did mention that wheel true and hub bearing pre-load are important but did not address the wheel itself. I started riding as a 180-200# sprinter. I was not a climber and light-weight stuff was never a consideration. Despite my recent weight loss that would allow me to ride lighter weight equipment my cheapness prevents me from buying new wheels (but I am willing to offer up my services to perform a long-term test of some high-end wheels). Having said that, I would not likely run the calipers as tight with a less stiff wheel.

    As a general matter, brake throw is a personal preference just like shoes, bibs, and saddles. The big difference is that while you can just throw on a new pair of bibs and go ride, changing the brake caliper means a few other considerations. But I do all sorts of weird personal preference things like angling the brake lever/hood in toward the longitudinal center line. It is fun to watch people who know bike set-up stare at them with a look of disapproval. I have come to the point where I just wait to see if they will ask why anyone would run the levers like that.

    One question for you.

    “It’s not a huge deal on Shimano or SRAM brakes, but with Campy, opening up the brake lever isn’t something you file under advisable.”

    I moved from Shimano to Campy (Record 10, perhaps the Record 11 is different) and know that the manner in which you open the caliper is different but am not sure I see why it is not advisable. I see that with the Shima no-no you can open them to varying degrees while the Campy is either open or closed. However, the design of the Campy is such that I still get brake engagement at the same pull. Indeed that is one of the brilliant parts of the design. Having the lever release to get additional caliper opening means that the caliper will still engage at the same pull (i.e. same lever distance from the bar) whether it is open or closed. With the caliper opening device on the caliper, it is possible to run the caliper loose enough that with the caliper open, the brake pads will not engage the rim. So it is not a danger of opening up the caliper and not getting any braking on the Campy.
    If the worry is with the Campy mechanism closing by itself, I don’t see that either. The open closed buttons at the top of the levers on mine have a positive click when changing between open and closed so I can not see them changing on their own.
    If the worry is that the reach to the lever is greater, that is true but
    1) It is relatively small. On mine, in the drops, it is only about 15mm additional reach when they are open. If that was saddle height, I would worry but as a temporary adjustment to get around an out of true wheel, I think I could deal with it.
    2) You can always use the hands on the hoods riding position and the difference in lever position is negligible.
    So, what am I missing?


    1. Author
      Padraig

      I got several replies by e-mail that addressed brake setup and the desire to run the brakes with really short throw. Admittedly, I don’t see the attraction.

      Regarding Campy, I think the big issue there is that it’s not remotely practical to ride around with the lever open. Sure you can hit the brakes from the hoods, but I don’t know anyone who can grab an open Campy brake from the drops; you have to do something fairly extreme to try to reach the brake.

      Given the number of rides and races I’ve been on over the years where something happened to knock a wheel out of true, or broke a spoke (though that has happened far fewer times), I like knowing that if I hit something I can ride home without having to adjust my bike. That’s the first thing. The second is that I really think most riders will have superior control over the brakes once the lever is a little closer to the bar. There really isn’t much lever travel from first contact with the rim until the maximum amount of pressure has been applied that won’t lock up the wheel. There’s really no good reason not to have that point be closer to the bar.

  3. Mark LIvingood

    As you can probably surmise from the website, I’m a tandem cycling enthusiast.

    We see similar wear marks on the inside of an Alpha Q X2 fork mounted on our composite Calfee tandem and an Alpha Q X2 fork mounted on our steel Erickson tandem. From my perspective and experiences, they appear to come from two sources.

    The first is as you note, that low spoke count wheels do tend to deflect as you countersteer to initiate and arrest turns. The rear more so than the front on a tandem, given the compounding effect of rear wheel side loading that the physics of having much higher rider weights, a 6′ wheelbase and torsional frame deflection creates.

    However, we see these same rub marks on the Alpha Q X2 fork mounted to our Erickson tandem which has never been fitted with anything less than fairly robust, 36h conventionally built wheelsets. While I haven’t put a camera on the frame to record it, when switching between a steel fork and the Alpha Q X2 fork with the same rake (i.e., no change in steering trail), you can feel the change in how the tandem corners which I attribute to what I believe is a fair amount of lateral fork deflection. We’ve also fitted a more robust composite fork to the same tandem — a Reynolds Ouzo Pro — which did not exhibit the change in handling, even with it’s long rake / shorter steering trail.

    So, at least for heavier riders and tandems, there is most likely a compounding effect when you have both a very lightweight composite fork and a low spoke count wheel deflecting under those same countersteering forces that momentarily sideload the wheels.

    P.S. Can’t tell you how much I enjoy reading (and sometimes citing) your Blog. Long time fan who first really took note of your writing when you started Asphalt magazine and included an enjoyable article on tandem cycling, my little niche in the wide-world of cycling.

  4. Paul Feng

    First, I have just happily discovered RKP – always good to find quality writing about any of my passions, and cycling is on the upswing: in 2011 finally got around to replacing my 23 year old college road bike.

    “If you’re running Ksyriums or some other similar wheel that offers virtually no flex”

    I just recently picked up some n.o.s. 2009 Ksyrium Elites, which I believe are little different than the current vintage. I discovered front wheel flex in some out-of-saddle sprinting, which caused the spoke magnet to whack its sensor. So besides maintaining some brake clearance, I’ve learned that I need to maintain some magnet clearance. I’ve also ordered a new magnet that is purported to be strong, thus allowing greater clearance. (I refuse to go GPS until they are better and cheaper.)

    Thanks also Patrick for your observation in the comment above about longer throw and having the levers closer to the bars. My old tendency would be to keep the pads close and throw short. I’ll relax that now.

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