I'm 100% in agreement with Lou here, and in disagreement with Sheldon. I ride about the same size frames as Lou and have had basically the same experience regarding crank length - if you ride hills, you want them as long as can be without causing discomfort. Well, maybe not *you*, but that's how it works for me.
And since we're not speaking of classic lightweights but we ought to be, did anyone else read the piece in the most recent Cycle Sport about Brett Beau (I *know* I'm misspelling his name), a short, light climber of a few decades back who used to ride 177.5mm cranks? It sounds like he may have gone to excess in this regard.
Saddle height and crank length are, for me (as I just mentioned on the tandem list) two things to be increased to the point of discomfort (through gradual changes over a long period of time) then backed off slightly - that's the place where I'm most comfortable _and_ most efficient.
In the end I think it's all about one's personal biomechanics, and everyone should experiment for themselves, riding each possible crank length for at least a few weeks, preferably a few months, to see what the best compromise is.
Steve "I'd climb steps with shorter risers happily, thank you" Freides
LouDeeter@aol.com wrote:
>
> "This is a common misunderstanding. The "leverage" of a bicycle drive
> train, also known as "gain ratio" depends on the crank length, wheel
> diameter and the sizes of both sprockets."
>
> May not be leverage, but if I'm in a 39x26 gear with no lower gear, then that
> 172.5 crank sure feels better on a steep hill to me than a 170. If you don't
> change gears, then I just believe that if the lever arm is longer, then the
> force being applied at the pedals will create 'leverage'. At least that is
> the way the physics works for me. Lou Deeter, Orlando FL