Saturday, September 02, 2006

The only person in history with the saddle too high

So yesterday I had my bike fit at a shop. The guy set it up in a stationary trainer and watched me ride, then started tweaking stuff to try to make it better. The first thing he did was have me add some obnoxiously colored insoles with a corrective shim thing to my shoes. We'll have to see how I like them when I actually lay down some miles, but for now the fancy footbed seems to be a huge improvement.

Next there was some tweaking of the handlebar position, and then he lowered my saddle. A lot. I think I may be the only cyclist in NYC who was riding with it too high. The method I learned was to put the saddle at a height that required me to almost straighten my leg at the bottom of the stroke. I've also run into fit articles that talk about raising the saddle until the rider's hips have to dip to reach the bottom of the stroke, then backing off a quarter of an inch or so until they're stable again, and raising the saddle such that there's a little space, maybe a centimeter, between the bottom of the rider's foot if it's flexed and the leg's straight and the pedal. This guy wanted my knee to have a 30° angle between my upper and lower leg at the bottom of the stroke. I didn't let him put my saddle that low because it made the top of the stroke feel really cramped, especially in my right knee, which tends to be a little worse, but even though it feels really wierd to be so much lower over the pedals, I'm going to try it for a while. If my bike fit had worked, I wouldn't be having problems with longer rides, so it's time to try someone else's technique.

On thinking about it further, the "high as possible" method of saddle placement makes more sense on an old-style platform pedal, or one with loose toeclips. My leg pushes down most strongly when it's almost straight, so if the downstroke is the only part of my pedal stroke that generates power, a higher saddle position is more efficient.

I ride with clipless pedals, and can exert force on them in any direction. If my leg is almost straight, my hamstrings are in a position in which they have very little leverage, so the transition from the downward part of the circle to the upward part is going to be pretty inefficient. If the saddle position is lower, then my hamstrings are already in a position to do some good. Frequently, with physical performance stuff, inefficient and unhealthy are the same thing. So since I pedal in a circle, as opposed to alternate pushes on either side, the new position will, hopefully, be much better for me. Anyway, I'll try it for a while and see how it goes.

We also added some shims between the pedal axles and the crank to put the pedals out further. I think it'll need to go further still, but the shop would need to special order a part for that, so I'm going to put some mileage on the bike and see how I feel.

The last adjustment was just to change the stem. Since the saddle is lower, the handlebars need to be lower too, and the stem I had was too long to go low enough.

On my way out of the shop, I got a call for some work. So I haven't had a chance to try the bike over some actual mileage with the new fit. I think that I definitely deserve hotness points for driving a cargo van through Manhattan and then into Brooklyn in heavy traffic.

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