| 摘要 |
PURPOSE: To reduce dragging generated in the axial direction of a tire on a tread grounding face of a rib pattern, and restrain partial wear without reducing the effective grounding area of the tread. CONSTITUTION: An intermediate rib M12 is provided with a thin groove 5 of which the groove depth direction is slanted from a tread surface to the tread center side, and the intermediate rib M12 is divided into a wide width rib 12a on the tread center side and a narrow width rib 12b on the tread shoulder side each having the same tread height. The ratio W2 :/W1 of the width W2 of the narrow width rib 12b to the width W7 of the wide width rib 12a is set to be 1<=W2 /W1 <0.25, the slant angleαin the groove depth direction of the thin groove 5 against the direction of a tread face normal line and the slant angle,5 of the groove wall on the tread center side of the wide width rib 12a against the direction of a tread face normal line are set in the relation of 0<α<β, and the slant angleθof the tread face of the wide width rib 12a against the axial direction of a tire satisfies the relation of 3.4θ<=(a+β/2<=6.4θ. |
