| 摘要 |
PROBLEM TO BE SOLVED: To prevent the development of a crack on a narrow groove and its vicinity portion, by reducing the produced quantity of distorsion on the narrow groove and its vicinity portion provided on a shoulder rib. SOLUTION: A narrow groove 4 continuing in a tread peripheral direction is provided on a shoulder rib 3, demarcated on a tread side end portion by a peripheral direction main groove 2, and the depth (d) of the groove 4, formed toward the normal line direction of a tread, is made within a range of 0.3-1.5 times of the depth D of the peripheral direction main groove 2 and an width W is within a range of 0.3-5.0 mm. Moreover annular grooves 6 continuing toward the tread peripheral direction are provided on the tread center side groove wall 5 in the depth direction halfway of the groove 4. |
