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Old 02-25-10, 10:54 PM
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old's'cool 
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Originally Posted by Sixty Fiver View Post
The SA AW is considered to be one of the most efficient drives of any type with a 97% efficiency... because of cross chaining and their susceptibility to contamination a derailer system can lose efficiency very quickly.

This only speaks to the drive's efficiency... a wider gearing range can make a rider more efficient even if the drive is not.
Yeah, I figured that would draw some controversy. Needless to say, I am not one to cross-chain or let my chain & sprockets get appreciably contaminated. If I remember my mechanical engineering classes, planetary gears losses (compared to a chain drive) come from sliding action of gears (i.e. when not in direct drive) plus the multiplicity of gears.
bikcamper, great link!, I really enjoyed the tech article by Jim Gill.
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