A vehicle safety support system including a rim having an annular drop center portion straddled by a pair of radially outwardly projecting flange portions each having an annular outer edge of greater diameter than a minimum diameter of the drop center portion; a pneumatic tire mounted on the rim and comprising a pair of annular bead portions, each of the bead portions being sealably seated on a different one of the flange portions, and with the drop center portion of the rim and an inner surface of the tire defining an annular cavity. Also included are a plurality of circumferentially spaced apart elements each comprising an inner portion supported by the drop center portion and an outer portion adapted for movement between an inactive position in which the outer portion does not project into the cavity radially outside the annular edges and an active position in which the outer portion projects into the cavity radially outside the annular edges. In their inactive positions, the elements permit mounting of the tire on the rim and in their active positions, provide support in the event of inadvertent tire deflation.