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 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.

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 rear derailleur of a bicycle includes a fixing portion connected to a frame of the bicycle, a linkage assembly pivotally connected to the fixing portion, a moving portion pivotally connected to the linkage assembly, a chain guide assembly connected to the moving portion, a driving assembly, a rechargeable battery for providing an electrical energy required for the motor, a coil, and a wireless charging circuit for receiving an electric power of the coil for charging the rechargeable battery. The driving assembly includes a motor including and a driving gear assembly connected to the linkage assembly. The motor includes an output shaft for driving the driving gear assembly and for driving the linkage assembly to pivot via the driving gear assembly, thereby to drive the moving portion and the chain guide assembly to move. The coil receives an external charging power and is disposed on the fixing portion, the moving portion, or the linkage assembly.

A rear derailleur assembly for mounting to a bicycle having a frame. The rear derailleur assembly includes an upper body portion configured to operationally engage the rear derailleur assembly to the frame, a controller portion pivotally connected to the upper body, a lower body portion pivotally connected to the upper body and pivotally connected to the controller portion, and a chain cage assembly. The chain cage assembly includes at least two pulleys configured to engage a chain of the bicycle, and a one-piece chain cage configured to retain each pulley at a particular fixed position. Each pulley is rotatable relative to the one-piece chain cage at the particular fixed position of the pulley. The lower body portion is operationally connected to the one-piece chain cage and configured to allow the one-piece chain cage to pivot relative to the lower body portion.

A rear derailleur assembly for mounting to a bicycle having a frame. The rear derailleur assembly includes an upper body portion configured to operationally engage the rear derailleur assembly to the frame, a controller portion pivotally connected to the upper body, a lower body portion pivotally connected to the upper body and pivotally connected to the controller portion, and a chain cage assembly. The chain cage assembly includes at least two pulleys configured to engage a chain of the bicycle, and a one-piece chain cage configured to retain each pulley at a particular fixed position. Each pulley is rotatable relative to the one-piece chain cage at the particular fixed position of the pulley. The lower body portion is operationally connected to the one-piece chain cage and configured to allow the one-piece chain cage to pivot relative to the lower body portion.

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 derailleur system is provided that moves the derailleur cage in a substantially rectilinear path. The derailleur is mounted to a frame having a gear cassette mounted thereon. The gear cassette includes an axis of rotation. The derailleur includes a drive member engaging the gear cassette. The derailleur is positioned on the frame adjacent the gear cassette, and including a spatial linkage having a stationary link, a floating link, and a cage assembly having two pulleys each defining an axis of rotation. The drive member engages each of the pulleys. The path of the floating link is substantially linear through substantially its entire range of motion and variously aligns at least one of the pulleys with the gear cassette.