| 摘要 |
A pneumatic radial tire (1) has a double crown structure such that an annular recess portion (7) is arranged in the tread (6) at a given region in the widthwise direction thereof, in which the tread is divided into a central region (8), a middle region (9) and a side region (10), and at least one auxiliary reinforcing layer (5) is arranged on a belt (4) to as to substantially envelop a crown portion of the carcass (2) and the full outer surface of the belt, provided that a stretching ratio of cord in the auxiliary reinforcing cord layer (5) at positions corresponding to the central region (8) and side region (10) is equal to or greater than that at a position corresponding to the middle region (9), whereby the high-speed durability is improved together with the drainage property while controlling the increase of tire weight and cost as far as possible. <IMAGE> |
