A wheel for at least partially muscle-powered vehicles and two-wheeled vehicles includes a hub and a rim having a plurality of spoke holes and a plurality of spoke systems for connecting the hub with the rim. A spoke system includes a spoke and a spoke nipple. A reinforcing unit with a through hole between the rim and the spoke nipple is provided. The reinforcing unit is a disk-type and is configured curved about at least one longitudinal axis. The reinforcing unit has a convex inner rim contact surface for bearing against a concave orientation area of the rim matched thereto. The reinforcing unit has a concave outside surface at which a nipple accommodation is provided at a depression having a concave nipple contact surface with a narrower curvature for accommodating a matching, convex supporting area of the spoke nipple.