| 摘要 |
PROBLEM TO BE SOLVED: To improve performance on an icy road surface, by attaining the uniformity of a grounding pressure in a tire block surface, in a pneumatic tire. SOLUTION: In this pneumatic radial tire, a radius of curvature r1 in a peripheral direction of a tire external peripheral length of a block surrounded by a groove engraved on a tire surface makes a shape having a relation of r1>=2R or r1<=-2R by making R a radius of curvature in the tire external peripheral length. In addition, a radius of curvature r2 in a tire sectional direction of a block surrounded by a groove engraved on the tire surface makes a shape having a relation of r2>=3R or r2<=-3R by making R the radius of curvature in the tire external peripheral length. |
