US Patent 9016169 Bicycle sprocket

A bicycle sprocket is provided that includes an external peripheral edge part and an internal peripheral edge part. The external peripheral edge part has a plurality of metal sprocket teeth. The internal peripheral edge part is positioned radially inward of the external peripheral edge part. The internal peripheral edge part is integrally formed as a one-piece unit with the external peripheral edge part. The internal peripheral edge part has at least one recess that extends radially outward from an inner edge of the internal peripheral edge part toward the external peripheral edge part.