A drive device is configured to drive a drive part. The drive device includes a fluid coupling, an electric motor, and a human-powered drive unit. The electric motor is configured to drive the drive part through the fluid coupling. The human-powered drive unit is configured to drive the drive part through the fluid coupling.

A drive device is configured to drive a drive part. The drive device includes a fluid coupling, an electric motor, and a human-powered drive unit. The electric motor is configured to drive the drive part through the fluid coupling. The human-powered drive unit is configured to drive the drive part through the fluid coupling.

A device for retaining a bicycle chain on a sprocket includes a base plate defining a plurality of fastener openings centered on an origin. A center of each of the plurality of fastener openings is disposed at a first radial distance from the origin. The origin defines an axis extending substantially orthogonally from a plane defined by two lines extending from the origin and at least two centers of the centers of the plurality of fastener openings. A first guard is secured to the base plate and includes a first guard retaining surface including a first curved surface defined by a second radial distance from the axis that is greater than the first radial distance and a first guard guiding surface having a first end adjacent the first guard retaining surface and a second end distal from the first end. The first end is disposed at the second radial distance from the axis. The second end is disposed at a third radial distance from the axis. The third radial distance is greater than the second radial distance. A second guard is secured to the base plate and includes a second guard retaining surface including a second curved surface defined by the second radial distance from the axis. A second guard guiding surface has a first end adjacent the second guard retaining surface and a second end distal from the first end. The first end is disposed at the second radial distance from the axis. The second end is disposed at a fourth radial distance from the axis. The fourth radial distance is greater than the second radial distance.

A device for retaining a bicycle chain on a sprocket includes a base plate defining a plurality of fastener openings centered on an origin. A center of each of the plurality of fastener openings is disposed at a first radial distance from the origin. The origin defines an axis extending substantially orthogonally from a plane defined by two lines extending from the origin and at least two centers of the centers of the plurality of fastener openings. A first guard is secured to the base plate and includes a first guard retaining surface including a first curved surface defined by a second radial distance from the axis that is greater than the first radial distance and a first guard guiding surface having a first end adjacent the first guard retaining surface and a second end distal from the first end. The first end is disposed at the second radial distance from the axis. The second end is disposed at a third radial distance from the axis. The third radial distance is greater than the second radial distance. A second guard is secured to the base plate and includes a second guard retaining surface including a second curved surface defined by the second radial distance from the axis. A second guard guiding surface has a first end adjacent the second guard retaining surface and a second end distal from the first end. The first end is disposed at the second radial distance from the axis. The second end is disposed at a fourth radial distance from the axis. The fourth radial distance is greater than the second radial distance.

A sprocket and chain assembly for bicycles is revealed. The sprocket and chain assembly for bicycles includes a bicycle sprocket and a bicycle chain. A contact part of the bicycle sprocket and a contact part of the bicycle chain in contact with each other are made of a multi-layer clad metal which is composed of a first metal and a second metal. The first metal has higher hardness and density than the second metal. A surface material for the contact parts of the bicycle sprocket and the bicycle chain is the first metal for providing sufficient wear resistance and ensuring service life of both the bicycle sprocket and the bicycle chain. Moreover, the lightweight design of the bicycle sprocket and the bicycle chain is achieved and sufficient structural strength is provided by the contact parts made of the multi-layer clad metal.

A sprocket and chain assembly for bicycles is revealed. The sprocket and chain assembly for bicycles includes a bicycle sprocket and a bicycle chain. A contact part of the bicycle sprocket and a contact part of the bicycle chain in contact with each other are made of a multi-layer clad metal which is composed of a first metal and a second metal. The first metal has higher hardness and density than the second metal. A surface material for the contact parts of the bicycle sprocket and the bicycle chain is the first metal for providing sufficient wear resistance and ensuring service life of both the bicycle sprocket and the bicycle chain. Moreover, the lightweight design of the bicycle sprocket and the bicycle chain is achieved and sufficient structural strength is provided by the contact parts made of the multi-layer clad metal.

A bicycle chain lubricant that may be applied as a coating on a bicycle chain is a crystalline solid at ambient temperatures, yet when the chain is in motion the forces around internal components locally transforms the coating to a lubricous fluid. This increases chain efficiency in the drive train and reduces ware by limiting water and dirt access to chain internal components.

A drive sprocket can include a plurality of teeth for meshing with a drive member to transmit rotary motion. The drive member can include a plurality of engagement pockets engaging the teeth of the drive sprocket, where each tooth has a tooth profile defined by a first side comprising a first engagement surface and an opposite second side comprising a second engagement surface, which engagement surfaces are configured such that when driven, a tooth meshes to the engagement pocket at a first contact location on the first engagement surface and also at a second contact location on the second engagement surface.

The present disclosure relates to a chain ring having teeth positioned in one of three lateral positions. At least one tooth may be placed in each lateral position. At least half the teeth may be positioned in a middle lateral position. The teeth in the first and third lateral positions may apply opposing lateral forces to a bicycle drive chain.

The present disclosure relates to a chain ring having teeth positioned in one of three lateral positions. At least one tooth may be placed in each lateral position. At least half the teeth may be positioned in a middle lateral position. The teeth in the first and third lateral positions may apply opposing lateral forces to a bicycle drive chain.