| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the occurrence of cracking at groove bottom by restricting a shape of a groove outline of a longitudinal major groove. <P>SOLUTION: A groove outline of a longitudinal major groove 9 is formed of an inner wall portion 13 extending to the inside in a tire radial direction from an outer edge 9i on a tire equator side, an inner arc portion 14 continuous with the inner wall portion 13 and formed by an arc having a radius smaller than the curvature radius of the inner wall portion 13, an outer wall portion 15 extending to the inside in the tire radial direction from an outer edge 9t on a tread end Te side of the longitudinal major groove 9 and having a smaller length than the inner wall portion 13, an outer arc portion 16 continuous with the outer wall portion 15 and formed by an arc having a radius smaller than the curvature radius of the outer wall portion 15, and a groove bottom portion 17 extending straight toward the inner arc portion 14 from the outer arc portion 16 while being inclined inward in the tire radial direction. A groove bottom deepest portion 18 of the longitudinal major groove 9 is provided on the tire equator side from the center position G1 of the width of the groove. The curvature radius R1 of the inner arc portion 14 and the curvature radius R2 of the outer arc portion 16 satisfy the relationships of R1≥0.6 mm and R2≥2×R1. <P>COPYRIGHT: (C)2012,JPO&INPIT |
