WTF happened to my post?

I had commented that in the MPH lines, you're gearing was different by about a factor of 2. I.E. 48/18 in the first case and 48/9 in the second.

Gear inches: http://www.sheldonbrown.com/gloss_g.html#gearinch

Although they're more popular than sheldon would have you believe .

The main thing crank length is going to give you is a change in the way your legs work the pedals. Mathematically it's no different than changing the gearing, but practically it is a question of how big a circle do your legs "like" to move in? Finding that will result in your body producing the optimal amount of torque applied to the crank.