A bicycle derailleur apparatus for controlling bicycle speed includes a bicycle chain guide and a pair of moldable wires. The guide has opposite sides receiving a bicycle chain therebetween and is pivotally movable in a lateral direction toward and away from a bicycle frame portion mounting the guide. The moldable wires, disposed side-by-side and spaced apart, are mounted to the bicycle frame portion and have respective outer end portions attached to one guide side. By applying a predetermined electric current to the moldable wires at separate times their outer end portions deform from pliable states to respective acute and obtuse angular shapes relative to respective main portions thereof and thereby move the guide to shift the bicycle chain into engagement with one or the other of inner and outer derailleur sprocket gears of different diameter sizes to change the bicycle speed relative to the pedal cadence of a rider.

A transmission device for a bicycle includes a housing, a mandrel, an assembling member, a transmission assembly, a derailleur assembly and a clutch assembly. The mandrel is rotatably disposed on the housing and extends along an axial direction. The assembling member has a driving gear. The transmission assembly is rotatably disposed on the housing and engaged with the driving gear. The derailleur assembly includes a first derailleur gear and a second derailleur gear. The transmission assembly is engaged with the first derailleur gear and the second derailleur gear. The clutch assembly includes a clutch member.

A bicycle derailleur apparatus for controlling bicycle speed includes a bicycle chain guide and a pair of moldable wires. The guide has opposite sides receiving a bicycle chain therebetween and is pivotally movable in a lateral direction toward and away from a bicycle frame portion mounting the guide. The moldable wires, disposed side-by-side and spaced apart, are mounted to the bicycle frame portion and have respective outer end portions attached to one guide side. By applying a predetermined electric current to the moldable wires at separate times their outer end portions deform from pliable states to respective acute and obtuse angular shapes relative to respective main portions thereof and thereby move the guide to shift the bicycle chain into engagement with one or the other of inner and outer derailleur sprocket gears of different diameter sizes to change the bicycle speed relative to the pedal cadence of a rider.

A bicycle derailleur for operating a chain guide. The derailleur has primary actuator that imparts a primary displacement on the chain guide that has at least a component in an axial direction with respect to an assembly of toothed wheels. The derailleur also has secondary actuator that imparts a secondary displacement on the chain guide that has at least a component in a radial direction with respect to the assembly of toothed wheels. The secondary actuator can operate independently of the primary actuator.

A bicycle derailleur for operating a chain guide. The derailleur has primary actuator that imparts a primary displacement on the chain guide that has at least a component in an axial direction with respect to an assembly of toothed wheels. The derailleur also has secondary actuator that imparts a secondary displacement on the chain guide that has at least a component in a radial direction with respect to the assembly of toothed wheels. The secondary actuator can operate independently of the primary actuator.

A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.

A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.

A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.

A bicycle derailleur is basically provided with a base member, a movable member and an electric actuator. The base member is configured to rotate together with a bicycle sprocket apparatus about a rotational axis of the bicycle sprocket apparatus. The movable member is movable relative to the base member to displace a bicycle chain. The electric actuator is configured to electrically actuate the movable member.

A bicycle derailleur is basically provided with a base member, a movable member and an electric actuator. The base member is configured to rotate together with a bicycle sprocket apparatus about a rotational axis of the bicycle sprocket apparatus. The movable member is movable relative to the base member to displace a bicycle chain. The electric actuator is configured to electrically actuate the movable member.