Originally Posted by
carleton
Leverage is one thing, but there is also footspeed.
Footspeed is the speed at which your foot is traveling in a circle. For a given cadence (say 100RPM) the foot must travel faster using longer cranks because the circumference of the pedal stroke is bigger. It will require less torque in the process, but the foot must travel faster.
I'll try to do the math...one sec...
That was the cadence difference I was referring to. Now that I know the term for it, I can better put it in words.
Given a the same footspeed on 170's, and applying it to 165's, it results in a ~3% faster cadence.