A power unit includes a drive unit and a power sprocket for engaging the transmission band of a bicycle. The power unit includes a first free-wheeling sprocket arranged on a first side of the power sprocket and a second free-wheeling sprocket arranged on a second side of the power sprocket. The power sprocket receives the transmission band from the first free-wheeling sprocket on the first side and passes the transmission band to the second free-wheeling sprocket.

A power unit includes a drive unit and a power sprocket for engaging the transmission band of a bicycle. The power unit includes a first free-wheeling sprocket arranged on a first side of the power sprocket and a second free-wheeling sprocket arranged on a second side of the power sprocket. The power sprocket receives the transmission band from the first free-wheeling sprocket on the first side and passes the transmission band to the second free-wheeling sprocket.

A swing arm includes an arm main body formed of a pipe member, and a reinforcement member configured to reinforce an axle support region of the arm main body. The arm main body has a notch formed by cutting out a portion of a region of a circumferential wall facing in a vehicle width direction. The reinforcement member is joined to the notch of the circumferential wall.

A swing arm includes a tubular arm main body and an axle support member configured to support an axle of a rear wheel, wherein a fixing surface for fastening and fixing the axle support member in the arm main body together with the axle is provided at an inner side-surface of the arm main body in a vehicle width direction, and an opening for inserting the axle support member is provided at an outer side-surface of the arm main body in the vehicle width direction.

An electronic automatically decoupling hub assembly is disclosed herein. The decoupling hub assembly has an axle and a hub shell rotationally positioned about the axle. A controller provides automatic activation/deactivation signals to an inductor. The decoupling hub assembly has a bearing rotationally positioned about the axle and a cassette body assembly, having a plurality of teeth, rotationally positioned about the bearing. One or more pawls are provided to engage with at least some of the teeth of the cassette body assembly and a seal is used to contain the pawls within the decoupling hub assembly. A cassette body assembly is coupled with the ratchet ring and an end cap is used to prevent a contaminant from entering into the decoupling hub assembly.

A bicycle derailleur pulley comprises a bearing region rotatable about an axis of rotation, a tooth region with teeth formed thereon for engaging into the chain, and a supporting structure that connects the bearing region and the tooth region. On at least one tooth of the chain-guiding pulley, on each of the inboard-side and outboard-side side surfaces thereof, there are formed guide regions for lateral guidance of the chain substantially parallel to the axis of rotation. At least one inboard-side guide region of the at least one tooth has an at least regionally reduced thickness dimension, relative to a central plane of the chain-guiding pulley, in relation to at least one outboard-side guide region, such that a chain section running substantially tangentially off the chain-guiding pulley can assume a greater skew angle in an outboard direction than in an inboard direction.

A bicycle derailleur pulley comprises a bearing region rotatable about an axis of rotation, a tooth region with teeth formed thereon for engaging into the chain, and a supporting structure that connects the bearing region and the tooth region. On at least one tooth of the chain-guiding pulley, on each of the inboard-side and outboard-side side surfaces thereof, there are formed guide regions for lateral guidance of the chain substantially parallel to the axis of rotation. At least one inboard-side guide region of the at least one tooth has an at least regionally reduced thickness dimension, relative to a central plane of the chain-guiding pulley, in relation to at least one outboard-side guide region, such that a chain section running substantially tangentially off the chain-guiding pulley can assume a greater skew angle in an outboard direction than in an inboard direction.

A belt tensioner for use with a bike is provided. The bike includes a frame and a belt. The frame includes a chain stay and a seat stay having a top surface and bottom surface. The belt tensioner includes a tensioner skeleton, a roller and a tension regulator. The tensioner skeleton is pivotally connected to the chain stay or the seat stay. An included angle is formed between the tensioner skeleton and chain stay or the seat stay. The roller is pivotally connected to the tensioner skeleton and in contact with the belt. The tension regulator presses against the belt to adjust tension of the belt. The tension regulator is disposed at an end of the tensioner skeleton, and the end of the tensioner skeleton is positioned distal to the bottom surface.

A belt tensioner for use with a bike is provided. The bike includes a frame and a belt. The frame includes a chain stay and a seat stay having a top surface and bottom surface. The belt tensioner includes a tensioner skeleton, a roller and a tension regulator. The tensioner skeleton is pivotally connected to the chain stay or the seat stay. An included angle is formed between the tensioner skeleton and chain stay or the seat stay. The roller is pivotally connected to the tensioner skeleton and in contact with the belt. The tension regulator presses against the belt to adjust tension of the belt. The tension regulator is disposed at an end of the tensioner skeleton, and the end of the tensioner skeleton is positioned distal to the bottom surface.

A bicycle rear derailleur has a base member mountable to a bicycle frame, a movable member movably coupled to the base member, a chain guide assembly rotatably connected to the movable member for rotation about a rotational axis, a biasing element configured and arranged to bias the chain guide assembly for rotation in a first rotational direction with respect to the movable member, and a fluid damper having a fluid cavity containing a volume of fluid. The fluid damper is operatively disposed between the chain guide assembly and the movable member to apply a damping force to the chain guide assembly when the chain guide assembly rotates in a second rotational direction opposite to the first rotational direction. The fluid damper has a guide wheel configured to route a chain and rotatable about the rotational axis.