A ring device for running with a flat tire and having articulated sectors is disclosed for a vehicle wheel equipped with a tubeless tire mounted on a one-piece rim with drop center, housed inside said tire and molding itself at least partially to the shape of the rim, the external surface of said ring being distant from the internal surface of the tread of the tire as long as the latter is in its normal operating condition, wherein said ring made from a composite material with a reinforced thermoplastic resin basis is formed so as to have in its part intended to come into contact with the rim drop center a stop lip for holding a bead of the tire in position, the other bead of which is subjected to the action of an elastomer wedge provided on the diametrical face of the ring opposite that carrying the stop lip, the articulated sectors being assembled together by mechanical fixing means providing positioning of the assembly of the ring and its component parts (elastomer wedge and stop lip) during actuation thereof.