Originally Posted by
elTwitcho
48x18 with 165 cranks will require more torque in a given rotation than 48x18 with 170 cranks to move the exact same speed.
not to be picky or anything, but the torque is also identical. T = F*r, where F is your leg pushing the pedal ('effort'), and r is crank length. keep T (ie: gear inches) constant...if r goes up, F goes down. which is the whole point...longer cranks provide more leverage ant the expense of pedal strike and/or lack of spin.