US Patent 9932090 Bicycle rear sprocket assembly

A bicycle rear sprocket assembly has a rotational center axis. The bicycle rear sprocket assembly comprises a first sprocket and a second sprocket. The first sprocket includes a first sprocket body and a first chain-engagement structure. The first sprocket body is made of a non-metallic material. The first chain-engagement structure is made of a metallic material and is configured to engage with a bicycle chain. The second sprocket includes a second sprocket body and a second chain-engagement structure. The second sprocket body is made of a non-metallic material and attached to the first sprocket body. The second chain-engagement structure is made of a metallic material and is configured to engage with the bicycle chain.