A derailleur comprises a base member, a movable member, a linkage structure, a pulley assembly, and a rotational force control structure configured to control rotational force of the pulley assembly relative to the movable member. The pulley assembly is pivotally movable relative to the movable member about a pivot axis in first and second directions. The pulley assembly is configured to move in the first direction upon moving from a second pivotal position toward a first pivotal position. The rotational force control structure includes a cam member having a first cam surface, an abutment member configured to abut the first cam surface, and a biasing member configured to bias the abutment member. The abutment member is configured to abut the first cam surface by the biasing member to apply first additional force to the pulley assembly in the first direction while the pulley assembly is in the first pivotal position.

A derailleur comprises a base member, a movable member, a linkage structure, a pulley assembly, and a rotational force control structure configured to control rotational force of the pulley assembly relative to the movable member. The pulley assembly is pivotally movable relative to the movable member about a pivot axis in first and second directions. The pulley assembly is configured to move in the first direction upon moving from a second pivotal position toward a first pivotal position. The rotational force control structure includes a cam member having a first cam surface, an abutment member configured to abut the first cam surface, and a biasing member configured to bias the abutment member. The abutment member is configured to abut the first cam surface by the biasing member to apply first additional force to the pulley assembly in the first direction while the pulley assembly is in the first pivotal position.

Chips removably attached to a bicycle frame allow different size hubs and axles to be connected to a frame. As the frame represents a major part of the investment in a bicycle, the chips allow a single frame to accommodate different wheels. The user can then use a wheel having the appropriate tire and attachments for the terrain to be traversed. For instance, a particular wheel and tire would be used for a downhill mountain trail, another wheel used for riding on paved surfaces and a third wheel hub would be used for loose surfaces, such as sand or gravel. Therefore, the user is able to adapt the bicycle for a variety of different terrains and uses.

Chips removably attached to a bicycle frame allow different size hubs and axles to be connected to a frame. As the frame represents a major part of the investment in a bicycle, the chips allow a single frame to accommodate different wheels. The user can then use a wheel having the appropriate tire and attachments for the terrain to be traversed. For instance, a particular wheel and tire would be used for a downhill mountain trail, another wheel used for riding on paved surfaces and a third wheel hub would be used for loose surfaces, such as sand or gravel. Therefore, the user is able to adapt the bicycle for a variety of different terrains and uses.

A rear sprocket assembly comprises a first sprocket, a second sprocket, and at least one tooth-position maintaining member. The at least one tooth-position maintaining member is configured to maintain a relative position between a plurality of first sprocket teeth and a plurality of second sprocket teeth in a circumferential direction with respect to a rotational center axis. The at least one tooth-position maintaining member includes a fixed portion and at least one guide portion. The fixed portion is configured to be fixed to one of the first sprocket and the second sprocket. The at least one guide portion is configured to engage with the other of the first sprocket and the second sprocket such that the other of the first sprocket and the second sprocket is slidable relative to the one of the first sprocket and the second sprocket in the axial direction.

A rear sprocket assembly comprises a first sprocket, a second sprocket, and at least one tooth-position maintaining member. The at least one tooth-position maintaining member is configured to maintain a relative position between a plurality of first sprocket teeth and a plurality of second sprocket teeth in a circumferential direction with respect to a rotational center axis. The at least one tooth-position maintaining member includes a fixed portion and at least one guide portion. The fixed portion is configured to be fixed to one of the first sprocket and the second sprocket. The at least one guide portion is configured to engage with the other of the first sprocket and the second sprocket such that the other of the first sprocket and the second sprocket is slidable relative to the one of the first sprocket and the second sprocket in the axial direction.

A bicycle gearshift mechanism has a base element, a pivot mechanism, a movable element, and a chain guide arrangement. The pivot mechanism connects the base element to the movable element. The chain guide arrangement is connected, rotatably about a rotary axle, to the movable element. The base element comprises a first attachment end, which is coaxial with respect to the rear-wheel axle or axis, and a second attachment end for coupling to the pivot mechanism

A bicycle gearshift mechanism has a base element, a pivot mechanism, a movable element, and a chain guide arrangement. The pivot mechanism connects the base element to the movable element. The chain guide arrangement is connected, rotatably about a rotary axle, to the movable element. The base element comprises a first attachment end, which is coaxial with respect to the rear-wheel axle or axis, and a second attachment end for coupling to the pivot mechanism

A bicycle rear derailleur includes a base member including a mounting portion configured to be attached to a bicycle frame, the mounting portion having a mounting opening through which a central axis of a hub axle passes in a mounting state of the bicycle rear derailleur. The mounting portion includes a single joint or is free of any joint. Also included is a movable member movably coupled relative to the base member and a linkage structure operatively connecting the movable member to the base member. Also included is at least one of a motor, a first wireless communication unit, and an electrical connector. The at least one of the motor, the first wireless communication unit, and the electrical connector are disposed on at least one of the base member, the movable member, and the linkage structure.

A bicycle derailleur comprises a circuit board, an electrical user interface, a motor housing, and a motor unit. The electrical user interface includes a user accessing portion configured to receive a user input. The motor housing includes a motor accommodating space. The motor unit is provided in the motor accommodating space and configured to generate rotational force and configured to be electrically connected to the circuit board. A first direction is defined from the circuit board toward the electrical user interface or from the electrical user interface toward the circuit board. The plurality of second directions is defined to be perpendicular to the first direction. The motor unit is at least partly provided between the user accessing portion of the electrical user interface and the circuit board when viewed in at least one of the plurality of second directions.