| 摘要 |
PROBLEM TO BE SOLVED: To restrain occurrence of cracking effectively, which is generated at the bottoms of fine grooves in the circumferential direction formed at both the axial ends of a tread part. SOLUTION: By forming a plurality of slits 36 extending from respective circumferential fine grooves 33 toward the axial inside so as to be separate form each other in the circumferential direction, the rigidity of a tread part 15 in the section where the slits 36 are formed is lowered, so that deformation of the section becomes easy. As a result, large strain generated near the axial inside corners of the circumferential fine grooves 33 are dispersed and reduced, so that strain at the groove bottom of the circumferential fine grooves 33 becomes approximate to each other at any position. |
