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Old 02-16-06, 12:18 PM
  #21  
beppe
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Originally Posted by vomitron
Just to clarify things, frame flex (specifically rear triangle/bb flex) does not "rob" you of power. As Klein pointed out, the rear triangle of a bike is a very efficient spring. If it flexes in a hard sprint, the energy will be returned to you on the next pedal stroke.
I call shenanigans. When you sprint, almost all of the force is applied on the downstroke. Even if Klein is correct, you still lose the energy on the downstroke, since the frame flexes (i.e., bends).

You get the power "back" (according to Klein) at the top and bottom of your pedal stroke, that is, when the pedals are at 6 and 12. This is also when you are pushing the frame to the opposite side, assuming you are out of the saddle. The power is essentially useless to you then--it won't back the bike go any faster.

I went from an incredibly flexy steel road bike -- though I didn't realize it at the time -- to a super-stiff aluminum-carbon frame, with all the components transferred over. I started climbing hills much faster than I could before.


Originally Posted by vomitron
Now, flex in wheels (lateral) makes a difference in power transfer. Stiff bars help you use your arms to stabilize yourself, thus letting you utilize your lower spinal erectors and hip flexors more in a sprint, which is what you want- look at how keirin racers sprint.
Agreed. Wheel flex is more of a big deal than frame flex.


/edited for prettiness

Last edited by beppe; 02-16-06 at 05:26 PM.
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