A hub-bearing unit (10) is provided with a bearing unit (30) having a radially outer ring (31), stationary, a radially inner ring (32), rotatable, and a double row of rolling bodies (33, 34), the first row of rolling bodies (33), axially outwards, being interposed between the radially outer ring (31) and a rotor-hub (20) and whose centers of the rolling bodies are located along a first circle having a radius (R), with respect to a symmetry axis (X) of the hub-bearing unit (10) and the second row of rolling bodies (34), axially inwards, being interposed between the radially outer ring (31) and the radially inner ring (32); the rotor-hub (20), rotatable, on top of which the radially inner ring (32) is assembled, the rotor-hub provided with a tubular portion (21), to which is steadily fixed a flange portion (23), axially external and provided with a plurality of fixing holes (24), whose axes are located along a second circle having a radius (r), with respect to the symmetry axis (X) of the hub-bearing unit (10); the radius (R) of the first circle of the rolling elements (33) centers is greater than the radius (r) of the second circle of the fixing holes (24) axes.
