Ebay Staton Gear/Chain Motorized Bike Kit



LR Jerry

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Mar 14, 2011
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1,230
What you have is an 18.75:1 gearbox driving a 15:16 ratio sprocket/freewheel. This gives you a total reduction of 20:1. The 7 speed freewheel (not a cassette) on the other side of the SI hub will determine the amount of pedal assist ratio you can give to the engine.

Most of the 4 strokes one could attach to the gearbox obtain max horsepower around 7000 rpm. Therefore with this setup max speed on level ground would be around 27 mph.
 
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