A chain guide for a bicycle having may include a base frame and a height adjustment member connected to the base frame and slidable relative to the base frame and lockable in a first position by engaging a first locking member. A retaining member may be pivotally connected to the height adjustment member and may be pivotable about a pivot axis a retaining position, in which the retaining member is positioned to obstruct lateral movement of the chain away from the chainring thereby preventing lateral misalignment between the chain and the chainring, and a removal position, in which the retaining member does not obstruct lateral movement of the chain away from the base frame while the height adjustment member is locked in the first position. The pivot axis may be spaced apart from the first locking member.

A chain guide for a bicycle having may include a base frame and a height adjustment member connected to the base frame and slidable relative to the base frame and lockable in a first position by engaging a first locking member. A retaining member may be pivotally connected to the height adjustment member and may be pivotable about a pivot axis a retaining position, in which the retaining member is positioned to obstruct lateral movement of the chain away from the chainring thereby preventing lateral misalignment between the chain and the chainring, and a removal position, in which the retaining member does not obstruct lateral movement of the chain away from the base frame while the height adjustment member is locked in the first position. The pivot axis may be spaced apart from the first locking member.

The disclosure provides a bicycle front derailleur including a fixed component, a chain guide, a first link, a second link, and a driving assembly. Two opposite ends of the first link are respectively disposed on the fixed component and the chain guide. The two opposite ends of the second link are respectively disposed on the fixed component and the chain guide. The driving assembly includes a driving shaft, a push component, an output gear and a power source. The push component and the output gear are fixed on the driving shaft, the power source is disposed on the fixed component and connected to the output gear, the push component is in contact with the first link, and the power source is configured to drive the push component to pivot the first link with respect to the fixed component via the output gear and the driving shaft.

A gear change mechanism for a bicycle may involve a tensioner that has a wheel engaged with a chain in a bicycle drivetrain. This tensioner may be configured to rotate or otherwise change orientation in response to slack in the chain to maintain tension in the chain. A sensor may be used to measure the orientation of a tensioner of a chain in a bicycle drivetrain, and/or the physical orientation of components indicative thereof. Actions may be triggered by signals generated by the sensor.

A gear change mechanism for a bicycle may involve a tensioner that has a wheel engaged with a chain in a bicycle drivetrain. This tensioner may be configured to rotate or otherwise change orientation in response to slack in the chain to maintain tension in the chain. A sensor may be used to measure the orientation of a tensioner of a chain in a bicycle drivetrain, and/or the physical orientation of components indicative thereof. Actions may be triggered by signals generated by the sensor.

An electrical seatpost assembly comprises a first cylinder, a second cylinder, a positioning structure, an electrical actuator, and a power supply. The second cylinder is telescopically received in the first cylinder. The positioning structure is to adjustably position the second cylinder relative to the first cylinder in a telescopic direction. The electrical actuator is to actuate the positioning structure in accordance with an electrical signal. The power supply is to supply electrical power to the electrical actuator. The power supply and the electrical actuator are disposed in one of the first cylinder and the second cylinder to at least partly overlap with each other when viewed from a direction perpendicular to the telescopic direction.

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 rocker for a bicycle gear that has an inner plate, an outer plate, a pair of pins integral with said inner and outer plates and a pair of toothed wheels arranged between them. Each toothed wheels is rotatably mounted on a respective pin. At least one pin is inserted in non-threaded through holes formed in the inner and outer plates and is defined by a screw with an outer threading and a female screw with an inner threading engaged with the outer threading.

A rocker for a bicycle gear that has an inner plate, an outer plate, a pair of pins integral with said inner and outer plates and a pair of toothed wheels arranged between them. Each toothed wheels is rotatably mounted on a respective pin. At least one pin is inserted in non-threaded through holes formed in the inner and outer plates and is defined by a screw with an outer threading and a female screw with an inner threading engaged with the outer threading.

A bicycle bracket element connects a bicycle frame to a rear gearshift mechanism of a derailleur system. The bracket element includes a first portion which has a cutout for receiving a portion of a bicycle rear wheel axle and a second portion which has a mounting opening to which the rear gearshift mechanism can be secured. The bracket element is formed with a region made from plastic and a region made from metal. The region made from plastic is fixedly connected to the region made from metal.