A bracket includes a fixing piece on a rotation element (3), said fixing piece comprising a body (22) in the general form of a ring, provided with an annular radial projection (23). The body includes an opening (33) which permits a variation in the diameter of said body (22) on assembly with engagement of the projection (23) in a corresponding groove (9) on the rotation element (3) to give a radial interference fit. A bar (28) prevents a variation in the diameter of the body (22) as above after the assembly thereof.