| 摘要 |
PURPOSE:To improve the water excluding function as well as to suppress an unblanced abrasion by making the small groove at the shoulder side edge of a rib neighboring the inner side of the outermost main groove at the right side and at the left side, and inclining the direction of the groove depth to the normal line of a tread surface to the inner side of the tire. CONSTITUTION:At the shoulder side edge of a rib 4 neighboring the inner side of the outermost main groove 2b, a small groove 4a continued in the tire circumferential direction is provided, and while the groove width W4 of the small groove 4a is made within 0.5 to 1mm, the groove depth direction is inclined to the inner side of the tire to the normal line of a tread surface. And a rib main body 4c and a small rib 4b which has the height lower than the rib main body 4c are formed, and the main groove side of the small rib 4b is made in a zigzag form. Furthermore, the largest width W2 of the small rib 4 to the whole width W1 of the rib 4 is made W2/W1<=0.3, and the angle alpha1 a side wall facing the main groove at the largest width part of the small rib 4b makes to the normal line of the tread surface is made smaller than the angle alpha2 made at the smallest width part, as alpha1<alpha2. |
