A sprocket assembly includes a sprocket including a center orifice and a bearing located in the center orifice with an outer part of the bearing fixed in relation to the sprocket. The sprocket assembly also includes a dust cover fixed in relation to an inner part of the bearing. An outer cover diameter of the dust cover is bigger than an outer bearing diameter of the bearing, so that an outer periphery of the dust cover extends radially past the outer part. The sprocket also includes an impeller arranged at the outer periphery of the dust cover. The impeller is fixed in relation to the sprocket.

A crank apparatus equipped with a labor-saving mechanism and a bicycle crank assembly are disclosed. The crank apparatus includes a crank mechanism, a transmission mechanism, a supporting module and a rotating arm module. The crank mechanism includes a crank, an axle-end gear and a pedal-end gear. The transmission mechanism includes a rotating axle having a circular groove. The supporting module is adapted to sheathe the rotating axle and includes an outer ring and rollers received inside the circular grooves and clamped between the rotating axle and the outer ring. The rotating arm module includes a first rotating arm and a second rotating arm. One end of the second rotating arm is connected to the first rotating arm, and another end of the second rotating arm is connected to the pedal-end gear. Accordingly, the transmission stability and useful lifetime of the crank apparatus and bicycle crank assembly are increased.

A rotating bicycle joint assembly includes a rotating joint part, a fixed joint part, and a bearing located between the rotating joint part and the fixed joint part. An outer part of the bearing is fixed in relation to one of the rotating joint part or the fixed joint part. An inner part of the bearing is fixed in relation to the other of the rotating joint part or the fixed joint part. A dust cover has an outer cover diameter that is bigger than an outer bearing diameter of the bearing, so that an outer periphery of the dust cover extends radially past the outer part. The rotating bicycle joint assembly also includes an impeller arranged at the outer periphery of the dust cover. The impeller is fixed in relation to the rotating joint part. The dust cover is fixed in relation to the inner part of the bearing.

A bottom bracket assembly with interconnected axle and crank arms. Each end of the axle has a plurality of angled surfaces and a recess formed with a depth through at least the axle perimeter and at least partially around the perimeter of the axle. Each crank arm has a slot formed a distance along the length such that the end of the crank arm is separated into two deflectable jaws. A bore is formed orthogonal to the slot and a fastener is installed in the bore, wherein the fastener has a length to span the slot in the crank arm to engage both deflectable jaws. The fastener has a shank radius that extends to a depth of the recess. Removal of the crank arm from the axle end is opposed when the fastener is in the bore.

A vehicle may include a pedal assembly, a motor assembly, and a drive unit that may be used to allow selective usage of one or both of the pedal assembly and the motor assembly to convey power to a driven wheel of the vehicle. The drive unit can include a gearbox that may enclose components which form at least part of a first power path between the pedal assembly and the driven wheel and a second power path between the motor assembly and the driven wheel. The first and second power paths can converge at a component within the gearbox. One-way bearings at points in the first and second power paths prior to the convergence of the power paths can inhibit or prevent the pedal assembly from being affected by operation of the motor assembly, and vice versa.