A sprocket assembly (1) to be mounted on a driver body (4) of a bicycle wheel with a truncated cone shell (2) having a first opening (21) in its small base and a second opening (22) in its large base, both openings being coaxial with the central axis (10) of said shell; a plurality of toothed sprockets (20) having different numbers of teeth for engagement with a chain; an axial fixing member (23), a radial load transmission profile (24) and a toothed torque transmission profile (25); wherein the truncated cone shell (2), the toothed sprockets (20), the axial fixing member (23), the radial load transmission profile (24) and the toothed torque transmission profile (25) are configured in a single piece; being the axial fixing member (23), the radial load transmission profile (24) and the toothed torque transmission profile (25) all disposed towards the inside of the truncated cone shell (2).