HUB-BEARING UNIT FOR A WHEEL OF A MOTOR VEHICLE

A hub-bearing unit with an axis of rotation includes a stationary, radially external ring, a radially internal flanged hub, rotatable about the axis and including a first shoulder, a second shoulder, a first relief groove, and a section (SR) radially opposite the first relief groove. At least one row of rolling bodies is interposed between the external ring and the flanged hub. The hub-bearing unit includes a first radial ball bearing and a second radial ball bearing interposed between a stem of a constant velocity joint and the flanged hub and opposite the first shoulder and the second shoulder. The second ball bearing mounts inside a seat of the flanged hub and a spacer axially abuts the second shoulder and mounts inside the seat between the second shoulder and the second ball bearing. The seat includes a second relief groove formed in an axially external position relative to section (SR).