An embodiment of the invention provides an electromechanical rear derailleur for a bicycle including a base member that is configured to be coupled to a frame member of a bicycle. The derailleur includes a movable member and a link mechanism that movably couples the movable member to the base member. A motor is positioned at the movable member to move the movable member.

An embodiment of the invention provides an electromechanical rear derailleur for a bicycle including a base member that is configured to be coupled to a frame member of a bicycle. The derailleur includes a movable member and a link mechanism that movably couples the movable member to the base member. A motor is positioned at the movable member to move the movable member.

A bicycle rear sprocket assembly comprises at least one sprocket. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.

A bicycle rear sprocket assembly comprises at least one sprocket having a total tooth number that is equal to or larger than 15. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.

A bicycle rear sprocket assembly comprises at least one sprocket having a total tooth number that is equal to or larger than 15. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.

A bicycle hub assembly comprises a hub axle, a hub body, a sprocket support body, and a freewheel structure. The sprocket support body includes at least ten external spline teeth configured to engage with a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external-spline driving surface and an external-spline non-driving surface. The freewheel structure includes a first ratchet member and a second ratchet member. The first ratchet member includes at least one first ratchet tooth. The second ratchet member includes at least one second ratchet tooth configured to engage with the at least one first ratchet tooth in a torque transmitting manner.

A bicycle hub assembly comprises a hub axle, a hub body, a sprocket support structure, and a brake-rotor support structure. The sprocket support structure includes a first torque-transmitting profile and a first externally-threaded portion. The first torque-transmitting profile is configured to transmit a rotational force between the sprocket support structure and a bicycle sprocket assembly. The first externally-threaded portion is configured to threadedly engage with a first internally-threaded portion of a first lock member. The brake-rotor support structure includes a radially external surface, a radially internal surface, and a second torque-transmitting profile configured to transmit a rotational force between the brake-rotor support structure and a brake rotor. The second torque-transmitting profile is provided on the radially external surface.

A bicycle hub assembly comprises a hub axle, a hub body, a sprocket support structure, and a brake-rotor support structure. The sprocket support structure includes a first torque-transmitting profile and a first externally-threaded portion. The first torque-transmitting profile is configured to transmit a rotational force between the sprocket support structure and a bicycle sprocket assembly. The first externally-threaded portion is configured to threadedly engage with a first internally-threaded portion of a first lock member. The brake-rotor support structure includes a radially external surface, a radially internal surface, and a second torque-transmitting profile configured to transmit a rotational force between the brake-rotor support structure and a brake rotor. The second torque-transmitting profile is provided on the radially external surface.

A clutch unit of a bicycle derailleur includes a main body, a cover for the main body, a positioning assembly, and a pressure-applying assembly. Both assemblies are received in a space between the main body and the cover. The main body has a top side with a receiving groove and is pivotally connected with a rotating shaft, which extends out of a bottom portion of the receiving groove. The positioning assembly includes a ratchet, a pawl, and an elastic member. The ratchet is pivotally connected in the receiving groove, can rotate with the rotating shaft, and has ratchet teeth annularly arranged at an equal spacing. The pawl is adjacent to and can move toward and away from the ratchet, has a meshing tooth for meshing with the corresponding ratchet tooth, and is elastically biased toward the ratchet by the elastic member. The pressure-applying assembly applies resistance to the ratchet.

A clutch unit of a bicycle derailleur includes a main body, a cover for the main body, a positioning assembly, and a pressure-applying assembly. Both assemblies are received in a space between the main body and the cover. The main body has a top side with a receiving groove and is pivotally connected with a rotating shaft, which extends out of a bottom portion of the receiving groove. The positioning assembly includes a ratchet, a pawl, and an elastic member. The ratchet is pivotally connected in the receiving groove, can rotate with the rotating shaft, and has ratchet teeth annularly arranged at an equal spacing. The pawl is adjacent to and can move toward and away from the ratchet, has a meshing tooth for meshing with the corresponding ratchet tooth, and is elastically biased toward the ratchet by the elastic member. The pressure-applying assembly applies resistance to the ratchet.