US Patent 6895834 Adjustable crank for bicycles

A crank arm of a bicycle having an effective crank arm length that can be selectively adjusted for increasing the comfort and performance of the rider. The crank arm includes a crank arm member rotatably connected about a crank arm member rotational axis to a base member. The base member includes a spindle bore defining a spindle rotational axis, which is eccentric with respect to the crank arm member rotational axis. The opposite end of the crank arm member includes a pedal bore defining a pedal rotational axis. The crank arm further includes a fastener to selectively couple the base member to the crank arm member for rotation therewith.