| 摘要 |
PURPOSE:To improve driving stability and a performance in winter, by forming a plurality of blocks provided with a tread to an inverted regular frustum shape, specifying an angle of its wall surface with a groove bottom surface and specifying an elastic ratio of tread rubber. CONSTITUTION:A tread pattern comprising blocks 2 sectioned by a plurality of grooves 1 is formed on a tire tread, each of blocks 2 being formed to an inverted regular frustum shape. More particularly, the area of a tread surface 2' is made larger than a base block area 2''. With this arrangement, the rigidity of the blocks 2 is reduced to increase a partial pressure in contact with the ground. In addition, the angle of the wall surface 3 of the block 2 with a groove bottom surface 4 is set at 85 deg.-60 deg. and an elastic ratio of the tread rubber at 0 deg.C is set to 10MPa-25MPa. With this arrangement, driving stability and a performance in winter are improved. |
