| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire capable of ensuring a high-level compatibility between wandering resistance and belt durability of the pneumatic radial tire by optimizing a grounding shape of a tread part stepping surface and a circumferential groove. SOLUTION: This tire 1 includes a pair of circumferential grooves 3a, 3b positioned at an equal distance through a tire equatorial plane E on a tread part 2. In the circumferential grooves 3a, 3b, a groove wall 4 on an inner side in the tire width direction is inclined to the inner side in the tire width direction, and a groove 5 on an outer side in the tire width direction is aligned with a normal line n<SB>2</SB>lined on a stepping surface of the tread part 2 or is inclined to the outer side in the tire width direction. An angleθ<SB>1</SB>formed by the groove wall 4 on the inner side in the tire width direction of the grooves 3a, 3b and a normal line 1 is larger than an angleθ<SB>2</SB>formed by a groove wall 5 on the outer side in the tire width direction and the normal line n<SB>2</SB>. Under a predetermined static load condition, a rectangular rate SR of a tread surface is within a range of 85 to 100%, and distances la, lb measured along in the tire width direction between a width center position of the grooves 3a, 3b and the tire equatorial plane E is within a range of 20 to 25% of a tread grounding width TW. COPYRIGHT: (C)2006,JPO&NCIPI |
