A mold and a method for manufacturing a support to be mounted on a rim of a vehicle by injection or transfer molding in which the molding material is force fed into a closed molding cavity. The mold includes an internal core for molding the inner surface of the support, upper and lower platens or shells for molding the body of the support and segments for molding the outer bearing surface. The mold includes a mechanism capable of imparting relative movement to the platens or shells which not only permits opening and closing of the mold but also ensures the specific movements of the core. The core includes at least three separable rigid parts: a center part and at least two complementary parts. The center part has two flat bearings, inclined at the same angle relative to the axis of the mold. These flat bearings are designed to cooperate with corresponding bearings arranged on each of the complementary parts to place the mold in a molding condition or in a stripping condition.