A sprocket guard assembly comprising a sprocket having sprocket radial spokes, and having teeth on an outer perimeter, the teeth disposed in a plane CL1, each sprocket radial spoke communicating with a first cylindrical surface, a circular member having circular member radial spokes, and each circular member radial spoke communicating with a second cylindrical surface, a collar having an outer cylindrical surface, a fastener engaging the collar, the first cylindrical surface and the second cylindrical surface engaging the outer cylindrical surface, all coplanar in a plane CL2, and plane CL1 is offset from plane CL2.

A bicycle chain comprises a first outer link plate and a second outer link plate. A first outer-link longitudinal axis extends through a first outer-link center axis and a second outer-link center axis to divide a first outer surface into a first side and a second side when viewed in an axial direction. A second outer-link longitudinal axis extends through a third outer-link center axis and a fourth outer-link center axis to divide a second outer surface into a third side and a fourth side when viewed in the axial direction. The fourth side includes a first circumferential area and a first chamfer free area. The first circumferential area has a first angle equal to or larger than 20 degrees. The first chamfer free area is adjacent to the first circumferential area. At least one second chamfer is provided outside the first chamfer free area.

A bicycle chain comprises a first outer link plate and a second outer link plate. A first outer-link longitudinal axis extends through a first outer-link center axis and a second outer-link center axis to divide a first outer surface into a first side and a second side when viewed in an axial direction. A second outer-link longitudinal axis extends through a third outer-link center axis and a fourth outer-link center axis to divide a second outer surface into a third side and a fourth side when viewed in the axial direction. The fourth side includes a first circumferential area and a first chamfer free area. The first circumferential area has a first angle equal to or larger than 20 degrees. The first chamfer free area is adjacent to the first circumferential area. At least one second chamfer is provided outside the first chamfer free area.

A bicycle sprocket is basically provided with a sprocket body and a plurality of chain-driving teeth. The sprocket body includes a central portion, an annular portion and an intermediate portion. The central portion has a central opening through which the rotational center axis passes and a plurality of internal splines for engaging external splines of a crank arm. The annular portion is disposed radially outward from the central portion with respect to the rotational center axis. The intermediate portion extends between the central portion and the annular portion in a radial direction about the rotational center axis. The plurality of chain-driving teeth extends radially outward from the annular portion of the sprocket body to engage with a bicycle chain. The sprocket body and the plurality of chain-driving teeth are formed as a one-piece, unitary member.

A bicycle sprocket is basically provided with a sprocket body and a plurality of chain-driving teeth. The sprocket body includes a central portion, an annular portion and an intermediate portion. The central portion has a central opening through which the rotational center axis passes and a plurality of internal splines for engaging external splines of a crank arm. The annular portion is disposed radially outward from the central portion with respect to the rotational center axis. The intermediate portion extends between the central portion and the annular portion in a radial direction about the rotational center axis. The plurality of chain-driving teeth extends radially outward from the annular portion of the sprocket body to engage with a bicycle chain. The sprocket body and the plurality of chain-driving teeth are formed as a one-piece, unitary member.

A velocipede includes a pedal crank for pedals to allow an operator to power the velocipede, and a transmission hub or component that is coupled to the pedal crank by a first chain or belt. The transmission component is located rearward of the pedal crank in the frame of the velocipede, such as under a seat position, and is further connected to a rear wheel at an output of the transmission component by a second chain or belt. The transmission has an output that is coupled to a rear wheel assembly. In some embodiments the rear wheel assembly can be mounted in a swingarm that pivots about a transverse axis defined by the output of the transmission. In some embodiments the rear wheel assembly can include an electric motor to drive a rear wheel.

A bicycle chain device that includes a mounting bracket configured to be affixed to a bicycle. The bicycle has a solitary bicycle front sprocket. A cage is movably mounted to the mounting bracket so that the cage is positioned adjacent to the front sprocket. The cage has a chain-receiving slot, through which a bicycle chain passes. The cage is configured to move in accordance with a shifting operation of a bicycle rear derailleur to maintain alignment with a chain to prevent the chain from falling off the sprocket.

An individual chain wheel for a bicycle front crank arrangement for engaging in a drive chain includes a plurality of teeth formed on a circumference of the chain wheel and having a first and a second group of teeth. The teeth of the second group of teeth are arranged in an alternating manner between the teeth of the first group of teeth. Each tooth has a load flank via which force is transmitted between an adjacent roller of the drive chain and the respective tooth. Each tooth of the first group may also have at least one profile with an opening in the vicinity of the flank, in which a portion of an inner link plate of the drive chain, which portion protrudes beyond the roller, engages.

An individual chain wheel for a bicycle front crank arrangement for engaging in a drive chain includes a plurality of teeth formed on a circumference of the chain wheel and having a first and a second group of teeth. The teeth of the second group of teeth are arranged in an alternating manner between the teeth of the first group of teeth. Each tooth has a load flank via which force is transmitted between an adjacent roller of the drive chain and the respective tooth. Each tooth of the first group may also have at least one profile with an opening in the vicinity of the flank, in which a portion of an inner link plate of the drive chain, which portion protrudes beyond the roller, engages.

A chainring installation structure includes a crank, a spindle, and a swing assembly. The spindle includes a first rotational axis, and one end of the spindle is connected to the crank. The crank drives the spindle to cause the spindle to rotate about the first rotational axis. The swing assembly is disposed at one end of the spindle adjacent to the crank without contacting the crank. The swing assembly can shift axially relative to the spindle. The swing assembly includes a second rotational axis that crosses the first rotational axis, in which the swing assembly can rotate about the second rotational axis.