| 摘要 |
PURPOSE:To reduce partial wear of a tread surface by setting the position of a boundary point between a center rubber layer and a shoulder rubber layer on the tread, the rubber-composition of the shoulder rubber layer and the difference in hardness of the shoulder rubber layer from the center rubber layer within a fixed range respectively. CONSTITUTION:On the tread part 5 of a radial tire 1, a center rubber layer 10 and a shoulder rubber layer 11 are formed in the tire axis direction separately inside and outside a point P on a tread 9 being 1.5-0.3 times the tread width W apart from a tire-equator C in the tire-axis direction. The shoulder rubber layer 11 is then formed by a rubber-composite body mixed with butadiene rubber in which the content of natural rubber(NR) and trans 1.4 bond is 54-70% at a weight part ratio of 85/15-20/, and containing 20-70 weight parts of carbon blacks of 10-30mum particle size. Further, Shore A hardness of the shoulder rubber layer 11 is set to be 2-6Hs more than the Shore A hardness of the center rubber layer 10. |
