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MT(5 posts)

MTGear ratio and torque question
Apr 3, 2001 11:24 AM
IF the gear ratios are the same when using a 39 or a 53 tooth chainring (changing only the rear cogs) will the rider feel any difference in pedal force required to maintain a speed or accelerate. when everything is the same.

SAme crank same bike same rider.
re: MTgrz mnky
Apr 3, 2001 12:27 PM
If I understand your question correctly you're asking that with the same drive ratio will there be any difference between using a 39 vs. a 53 up front? The answer is yes and no. No in the sense that since the drive ratios are the same then for all practical purposes the force/torque transmitted is the same. The no answer comes when you do a detailed analysis of a chain drive and realize that there is a littl e bit more ineffiency and loss when smaller gears are used. The chain is not a continuous belt, but rather a series of short segments with some very slight geometry changes as it enters and leaves the tooth of the gear. This is a very small difference and not likely to be noticed at the practical level. You could also have some loss if a high chain angle is used between front and rear gears, but this could happen in either chainring.
Grz mnky is right, smaller gears are less efficient in ...jimbob
Apr 3, 2001 3:40 PM
transfering power for the same given ratio. Less friction I would guess. I dont know about the "high angle" thing grease monkey mentioned.
re: MTDug
Apr 3, 2001 12:57 PM
Gear Ratios are NOT the same with a 39 and a 53. Therefore your question is moot.
re: MTLazy
Apr 3, 2001 1:34 PM
Does that mean that 1/2 is not the same as 50/100?