If I may contribute my own anecdote: after a fitter recommended that I try longer cranks (am tallish at 6'1" and was riding 170's), I fooled around with 172.5's and 175s for two years, and had trouble with knee pain on and off during that time (am also a wannabe ultra-distance rider). I am now back on 170s and will likely stay there---although of course I can't be sure about this, the shorter length just seems to make it easier to achieve an ergonomic position given my own anatomical quirks.
Andrew Hartline Vancouver, British Columbia Canada
On 24-Jul-10, at 1:14 PM, John Wood wrote:
> On Sat, Jul 24, 2010 at 1:41 PM, verktyg <email@example.com> wrote:
>> I think that starting off with lower gears, lowering your seat and
>> pedals that allow your feet to move around are far more important
>> than crank
>> arm length.
> Good advice. Lower saddle, lower gears, and lots of float are no
> important, but I also know that switching to shorter cranks made a
> noticeable improvement for me. It was the final piece of the
> puzzle, and
> for me, seemed to have the greatest effect.
> John Wood
> Open Road Bicycles
> Missoula, Montana, USA