A sprocket assembly includes a sprocket body preferably made of aluminum and at least one sprocket preferably made of steel. The sprocket assembly may include one, two, three, or more than three sprockets assembled around a central axis in the sprocket body. The sprockets have an internal design shaped to transfer the torque and the teeth on the sprocket transfer the torque to a chain or toothed belt. The steel sprockets are preferably co-molded with the aluminum sprocket body. In some embodiments, the sprocket assembly also includes at least one steel insert for each steel sprocket.

The present application describes a transmission system, including a certain tooth profile of toothed wheel and its use. This transmission system enables an improved guidance of the chain by using a non-normative tooth profile, to avoid that when the vehicle is exposed to extreme situations disengagements of the chain may occur. This transmission system applies to vehicles, preferably bicycles.

A bicycle sprocket arrangement comprises a smaller sprocket and a larger sprocket. The larger sprocket has at least one upshifting facilitation area configured to facilitate an upshifting operation in which a bicycle chain is shifted from the larger sprocket toward the smaller sprocket. The at least one upshifting facilitation area includes an upstream tooth, an intermediate tooth, and a downstream tooth. The upstream tooth has a first recessed portion. The intermediate tooth has a second recessed portion. The downstream tooth has at least one of a third recessed portion and a chamfered portion. The at least one of the third recessed portion and the chamfered portion are separated from the second recessed portion.

A bicycle sprocket arrangement comprises a smaller sprocket and a larger sprocket. The larger sprocket has at least one upshifting facilitation area configured to facilitate an upshifting operation in which a bicycle chain is shifted from the larger sprocket toward the smaller sprocket. The at least one upshifting facilitation area includes an upstream tooth, an intermediate tooth, and a downstream tooth. The upstream tooth has a first recessed portion. The intermediate tooth has a second recessed portion. The downstream tooth has at least one of a third recessed portion and a chamfered portion. The at least one of the third recessed portion and the chamfered portion are separated from the second recessed portion.

A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, an axially outward protuberance, and an axially inward protuberance. The axially outward protuberance is disposed on an outward facing side of the sprocket body to overlap at least partly with a bicycle chain engaging with a neighboring bicycle sprocket when viewed along a rotational center axis. The axially inward protuberance is disposed on an inward facing side of the sprocket body to overlap at least partly with the axially outward protuberance when viewed along the rotational center axis.

A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, an axially outward protuberance, and an axially inward protuberance. The axially outward protuberance is disposed on an outward facing side of the sprocket body to overlap at least partly with a bicycle chain engaging with a neighboring bicycle sprocket when viewed along a rotational center axis. The axially inward protuberance is disposed on an inward facing side of the sprocket body to overlap at least partly with the axially outward protuberance when viewed along the rotational center axis.

A bicycle chain ring for engaging a chain link of a bicycle chain, the bicycle chain ring including an inner edge fully circumscribing both an opening and an axis of rotation, an inner surface extending between the inner edge and an outer edge where a plurality of chain ring teeth emanate, and a plurality of ramps disposed about the inner surface, wherein at least one of the plurality of ramps includes a lifting surface for initiating lift of a bicycle chain without assistance from the plurality of chain ring teeth. The lifting surface extends radially along the inner surface toward the outer edge, and the at least one ramp has a first end proximate the inner edge and a second end proximate the outer edge. The second end of the at least one lifting surface terminates before reaching the bottom of a trough positioned between two or more of the plurality of chain ring teeth.

A bicycle chain ring for engaging a chain link of a bicycle chain, the bicycle chain ring including an inner edge fully circumscribing both an opening and an axis of rotation, an inner surface extending between the inner edge and an outer edge where a plurality of chain ring teeth emanate, and a plurality of ramps disposed about the inner surface, wherein at least one of the plurality of ramps includes a lifting surface for initiating lift of a bicycle chain without assistance from the plurality of chain ring teeth. The lifting surface extends radially along the inner surface toward the outer edge, and the at least one ramp has a first end proximate the inner edge and a second end proximate the outer edge. The second end of the at least one lifting surface terminates before reaching the bottom of a trough positioned between two or more of the plurality of chain ring teeth.

The present disclosure describes a gearshift mechanism for adjusting a gear ratio between a traction means, such as a chain, and a multi-sprocket gear set which can be rotated around an axle. The gearshift mechanism is configured to move the traction means in relation to the sprockets, such that an adjustment element is moved into the rolling motion of the traction means, thereby causing movement off of one sprocket and movement onto another sprocket.

The present disclosure describes a gearshift mechanism for adjusting a gear ratio between a traction means, such as a chain, and a multi-sprocket gear set which can be rotated around an axle. The gearshift mechanism is configured to move the traction means in relation to the sprockets, such that an adjustment element is moved into the rolling motion of the traction means, thereby causing movement off of one sprocket and movement onto another sprocket.