| 摘要 |
A pneumatic radial tire, particularly a large-size and low-section profile pneumatic radial tire for trucks and buses, develops improved bead portion durability by providing a stiffener (7) disposed between a main body portion (5a) and a turnup portion (5b) of a carcass (5) as a one-piece molded body of two or more rubber compositions having different hardnesses, in which a rubber composition (7-1) having a highest hardness is arranged near to the main body portion (5a) of the carcass (5) at least at the side of the tread portion (3) as a deformation-isolating rubber member having a greatest thickness (Tmax) at a position separated from a line (Lv) drawn from an end (5bE) of the turnup portion (5b) toward an outer surface of the carcass main body portion (5a) in the tire section, and a rubber composition (7-2) having a lower hardness is arranged along an inner surface of the turnup portion (5b). <MATH> |
