No Rocket Surgeon
Join Date: Jan 2005
Location: Corona and S. El Monte, CA
Bikes: Cannondale D600, Dahon Speed T7
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Well, your knees and body don't see a torque, they see force. Torque applied to your knees is really bad!
Bearing see very little torque, providing the drag due to lubrication or binding is neglegible.
Chains see no torque, only force.
For the purposes of a chain-driven bicycle, torque is the tangential force times the radius at which it is applied. For example, a force of 10 lbf applied tangentially to a sprocket at a distance 2" will give you a torque of 20 in-lbf.
(For the time being, please don't argue with me about in-lbf, vs. lbf-in as a unit of torque. That's another discussion
If you want to apply a specific torque to the rear wheel, the tangential force would be less the further it is from the center of rotation. Hence, for the same torque, the larger sprocket on the rear cluster will require a lower tangential force than your smallest sprocket would. For example:
2" * 10 lbf = 20 in-lbf = 4" * 5 lbf
Does this answer your question?
I think the short answer to your question is yes. Proper gearing will reduce the force you have to apply to the pedals. Unless you're really strong, don't push those tall gears. Your knees will thank you.
Fewer Cars, more handlebars!
Last edited by eubi; 10-24-07 at 10:16 AM.