| 摘要 |
PURPOSE:To maintain excellent traction performance for a long term by providing a siping independent of a main groove at a rib on a tread surface or on the surface of a block, specifying its depth and length and forming a cross section into a shape widening toward the end in the direction of its depth. CONSTITUTION:In a pneumatic tire having four main grooves 2 arranged annularly in a tire peripheral direction on a tread surface 1, and ribs 3, 4, 5 provided on a shoulder part, a central part and between them on the tread surface 1 respectively, a siping 7 independent of the main groove 2 is provided on the surface of the rib 3 forming a tread pattern of the tread surface 1, and its depth is established to be 70-120% as much as the depth of the main groove 2. Length in the tire axial direction of the siping 7 is established to be 10-35% as much as the width in the tire axial direction of the rib 3 to which the siping belongs. In addition, a shape in the cross sectional direction including a tire axis of the siping 7 is formed into a shape widening toward the end in the direction of its depth. |
