Abstract: A relatively simple and highly efficient safety system for retaining the tires, which are mounted on the front wheels of heavy, over-the-road vehicle such as trucks, buses and the like, in the event of gradual or sudden deflation of the tires. Such tires are locked onto rims of the two or three-piece types, mounted on disc or spoked wheels. The important and essential features of the present invention reside in the provision of a radially - extending locking lug detachably mounted on and rigidly secured to a spoke of the wheel or in the ventilating holes in disc wheels and which terminates at its outer end in a position to contact the outer flange of a two-piece rim installation, or in the case of a three-piece rim installation, to contact the outer flange and to overlie the radially-split locking ring.