A rear sprocket assembly comprises a first sprocket, a second sprocket, and at least one tooth-position maintaining member. The at least one tooth-position maintaining member is configured to maintain a relative position between a plurality of first sprocket teeth and a plurality of second sprocket teeth in a circumferential direction with respect to a rotational center axis. The at least one tooth-position maintaining member includes a fixed portion and at least one guide portion. The fixed portion is configured to be fixed to one of the first sprocket and the second sprocket. The at least one guide portion is configured to engage with the other of the first sprocket and the second sprocket such that the other of the first sprocket and the second sprocket is slidable relative to the one of the first sprocket and the second sprocket in the axial direction.

A transmission mechanism includes a chain. The chain includes a plurality of inner link units and a plurality of outer link units. Each of the inner link units includes two inner chain plates. Each of the inner chain plates has an inner waist section. At least one of the outer link units includes two outer chain plates. Each of the outer chain plates has an outer waist section that has a protruding part and a recessed part. A distance between the inner waist sections of each of the inner link units is smaller than a distance between the protruding parts of the outer chain plates of the at least one of the outer link units, and is equal to or smaller than a distance between the recessed parts of the at least one of the outer link units.

A bicycle component controller is basically provided with a data storage device and a processor. The data storage device contains sprocket assembly information of at least one sprocket assembly. The processor is configured to perform a gear shift control based on the sprocket assembly information. The sprocket assembly information of the at least one sprocket assembly at least includes a total sprocket number and shifting gate information. The single shifting distance of the sprocket assembly information corresponds to an axial spacing between adjacent sprockets of the at least one sprocket assembly.

A bicycle sprocket wheel unit includes multiple section units connected to each other. Each section unit has teeth formed on the outer periphery thereof. Each section unit has at least one fixing device that is connected to a mounting unit. The mounting unit is made by way of pressing to form an integral ring plate which includes a hub connection hole defined in the center thereof. A first disk, a second disk and a third disk are connected to the mounting unit and share the center of the hub connection hole. A first sprocket wheel and a second sprocket wheel are respectively located on two sides of the third disk. The second disk is connected to a third sprocket wheel and a fourth sprocket wheel. The third disk is riveted to the first and second sprocket wheels along the whole face thereof to reinforce lateral strength of the sprocket wheels.

A bicycle sprocket wheel unit includes multiple section units connected to each other. Each section unit has teeth formed on the outer periphery thereof. Each section unit has at least one fixing device that is connected to a mounting unit. The mounting unit is made by way of pressing to form an integral ring plate which includes a hub connection hole defined in the center thereof. A first disk, a second disk and a third disk are connected to the mounting unit and share the center of the hub connection hole. A first sprocket wheel and a second sprocket wheel are respectively located on two sides of the third disk. The second disk is connected to a third sprocket wheel and a fourth sprocket wheel. The third disk is riveted to the first and second sprocket wheels along the whole face thereof to reinforce lateral strength of the sprocket wheels.

Provided is a strong and lightweight sprocket. A sprocket according to one aspect of the present invention comprises: attachment holes 20 formed at equal intervals in the circumferential direction; a plurality of sprocket teeth 30 provided to the outer periphery; first openings 40 formed into substantially triangular shapes of which two corners each face an attachment hole 20 and the remaining corner is positioned toward the outer periphery; and second openings 50 that are formed into substantially triangular shapes of which one corner faces an attachment hole 20 and the remaining two corners are positioned toward the outer periphery, and that, with the first openings 40, demarcate first crossbars 70 with which driving force and load reaction force align and second crossbars 80 with which driving force and load reaction force conflict.

Provided is a strong and lightweight sprocket. A sprocket according to one aspect of the present invention comprises: attachment holes 20 formed at equal intervals in the circumferential direction; a plurality of sprocket teeth 30 provided to the outer periphery; first openings 40 formed into substantially triangular shapes of which two corners each face an attachment hole 20 and the remaining corner is positioned toward the outer periphery; and second openings 50 that are formed into substantially triangular shapes of which one corner faces an attachment hole 20 and the remaining two corners are positioned toward the outer periphery, and that, with the first openings 40, demarcate first crossbars 70 with which driving force and load reaction force align and second crossbars 80 with which driving force and load reaction force conflict.

A bicycle sprocket comprises a sprocket body and a plurality of chain-driving teeth. The plurality of chain-driving teeth comprises a first tooth and a second tooth. The first tooth has a first radial length radially defined from a reference line to a first radially outermost end. The second tooth has a second radial length radially defined from the reference line to a second radially outermost end. The second radial length is in a range of 1.5 mm to 2.9 mm. A shortest distance is defined between the downstream circumferential surface and a first intersection point of the circumferential center plane and an additional reference line. The shortest distance is equal to or larger than 2.0 mm. The additional reference line is defined at a reference position radially outward spaced apart from the reference line by 1.5 mm.

A bicycle sprocket comprises a sprocket body and a plurality of chain-driving teeth. The plurality of chain-driving teeth comprises a first tooth and a second tooth. The first tooth has a first radial length radially defined from a reference line to a first radially outermost end. The second tooth has a second radial length radially defined from the reference line to a second radially outermost end. The second radial length is in a range of 1.5 mm to 2.9 mm. A shortest distance is defined between the downstream circumferential surface and a first intersection point of the circumferential center plane and an additional reference line. The shortest distance is equal to or larger than 2.0 mm. The additional reference line is defined at a reference position radially outward spaced apart from the reference line by 1.5 mm.

A first sprocket includes a first opening having a first diameter smaller than a radially outer diameter of a sprocket support portion of a bicycle rear hub assembly. A lock member includes a main body, a male thread portion, and a radial projection. The main body has a first axial end configured to pass through the first opening and a second axial end opposite to the first axial end in an axial direction. The male thread portion is provided to the first axial end and configured to engage with a female thread portion of the bicycle rear hub assembly in a state where a bicycle rear sprocket assembly is mounted to the bicycle rear hub assembly. The radial projection extends radially outwardly from the second axial end to restrict axial displacement of the first sprocket with respect to the sprocket support portion in the state.