| 摘要 |
A crank assembly for a bicycle uses a chain and a plurality of auxiliary sprockets to achieve high ratios of wheel speed to pedal-rotation speed. The crank assembly is designed for use on a full-suspension bicycle, as the relative motion of the drive sprockets (22) of the transmission is isolated from the motion of the rear suspension arms (18, 20), which form the chain stays of the bicycle, and whose pivot is co-axial with the axle of the pedal cranks (14). Motion of the suspension arms about the pivot induces rotation by an equal angular measure of the drive sprocket of the transmission. So no relative motion of the drive sprocket and suspension arms occurs except that which is induced by the pedal cranks.
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