Abstract: The tire vulcanizing mould includes a plurality of segments for molding the outside of the tire tread. The segments are able to move radially between a position in which the mold is open and a position in which the mold is closed. The segments have frustoconical bearing surfaces that are placed radially on the outside. An axially mobile external ring, which acts on the frustoconical bearing surfaces, is placed radially on the outside of the segments in order to cause them to close and to move back from their position of closure in the mold. The external ring is radially preloaded towards the inside when the mold is in the open position.