Systems and methods are provided for actively controlling a derailleur. A derailleur system includes a cassette including a number of sprockets, a drive unit that drives the cassette, and a chain linking the drive unit with the cassette. A derailleur is configured to guide the chain around the cassette, the derailleur including a swing arm rotatable at a pivot assembly to maintain tension on the chain. A lock selectively locks the swing arm from rotating.

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.

Systems and methods are provided for actively controlling a derailleur. A derailleur system includes a cassette including a number of sprockets, a drive unit that drives the cassette, and a chain linking the drive unit with the cassette. A derailleur is configured to guide the chain around the cassette, the derailleur including a swing arm rotatable at a pivot assembly to maintain tension on the chain. A lock selectively locks the swing arm from rotating.

Systems and methods are provided for actively controlling a derailleur. A derailleur system includes a cassette including a number of sprockets, a drive unit that drives the cassette, and a chain linking the drive unit with the cassette. A derailleur is configured to guide the chain around the cassette, the derailleur including a swing arm rotatable at a pivot assembly to maintain tension on the chain. A lock selectively locks the swing arm from rotating.

A rear derailleur of a bicycle is disclosed. The rear derailleur includes a four-bar linkage. A fixing pin is received in a blind inner cavity of a base body and a fixing screw is constrained to a frame. A spring loading insert is arranged in the blind inner cavity. The base body is rotatable with respect to the spring loading insert. Connection members are inserted in seats formed on the fixing screw and on the spring loading insert to axially constrain the fixing screw and the spring loading insert. A toothed sector is mounted coaxially to the spring loading insert and is active on a sprocket which is active on the base body. A torsion spring is active between the spring loading insert and the toothed sector and is configured to constrain the spring loading insert and the toothed sector in rotation during controlled movements of the chain guide.

A rear derailleur of a bicycle is disclosed. The rear derailleur includes a four-bar linkage. A fixing pin is received in a blind inner cavity of a base body and a fixing screw is constrained to a frame. A spring loading insert is arranged in the blind inner cavity. The base body is rotatable with respect to the spring loading insert. Connection members are inserted in seats formed on the fixing screw and on the spring loading insert to axially constrain the fixing screw and the spring loading insert. A toothed sector is mounted coaxially to the spring loading insert and is active on a sprocket which is active on the base body. A torsion spring is active between the spring loading insert and the toothed sector and is configured to constrain the spring loading insert and the toothed sector in rotation during controlled movements of the chain guide.

A bicycle drive includes a multi-sprocket arrangement for rotatable mounting on a rear-wheel axle an engagement with a bicycle chain having inner link plate pairs and chain outer link plate pairs. The multi-sprocket arrangement includes a sprocket having, between an axial inner side and an oppositely situated axial outer side, a flat sprocket body and a plurality of teeth formed on a circumference of the sprocket. The plurality of teeth include at least one tooth of a first tooth group, the axial width of which is dimensioned to be greater than a chain inner link plate spacing and smaller than a chain outer link plate spacing, and a second tooth group, the axial width of which are dimensioned to be smaller than the chain inner link plate spacing.

A bicycle drive includes a multi-sprocket arrangement for rotatable mounting on a rear-wheel axle an engagement with a bicycle chain having inner link plate pairs and chain outer link plate pairs. The multi-sprocket arrangement includes a sprocket having, between an axial inner side and an oppositely situated axial outer side, a flat sprocket body and a plurality of teeth formed on a circumference of the sprocket. The plurality of teeth include at least one tooth of a first tooth group, the axial width of which is dimensioned to be greater than a chain inner link plate spacing and smaller than a chain outer link plate spacing, and a second tooth group, the axial width of which are dimensioned to be smaller than the chain inner link plate spacing.

A rear derailleur of a bicycle is disclosed. The rear derailleur includes a four-bar linkage. A fixing pin is received in a blind inner cavity of a base body and a fixing screw is constrained to a frame. A spring loading insert is arranged in the blind inner cavity. The base body is rotatable with respect to the spring loading insert. Connection members are inserted in seats formed on the fixing screw and on the spring loading insert to axially constrain the fixing screw and the spring loading insert. A toothed sector is mounted coaxially to the spring loading insert and is active on a sprocket which is active on the base body. A torsion spring is active between the spring loading insert and the toothed sector and is configured to constrain the spring loading insert and the toothed sector in rotation during controlled movements of the chain guide.