Patent ID: 8701729

Claim:
A pneumatic radial tire comprising: a carcass ply which extends between bead cores arranged in a pair of bead portions, and is wound up to an outer side in a tire radial direction around the bead cores; and a chafer which is arranged in such a manner as to wrap around the carcass ply from an inner side to an outer side in a tire width direction, around the bead core, wherein an inner end of the chafer positioned in the inner side in the tire width direction is arranged in the outer side in the tire radial direction than a winding end of the carcass ply, and a reinforcing rubber tapering off toward the outer side in the tire radial direction provided adjacently to the outer side in the tire radial direction of the inner end of the chafer and further wherein the reinforcing rubber has a triangular portion which is adjacent to the inner end of the chafer from the outer side in the tire radial direction, an extension portion which extends from the inner end toward the inner side in the tire radial direction along the chafer and is adjacent to the chafer from the inner side in tire width direction, and an extension portion which extends from the inner end toward the inner side in the tire radial direction along the chafer and is adjacent to the chafer from the outer side in the tire width direction wherein a thickness of the reinforcing rubber is equal to or more than 3 mm at a position in the inner end of the chafer, and a distance from the inner end of the chafer to a leading end of the reinforcing rubber is equal to or more than 30 mm.