| 摘要 |
PURPOSE:To secure high sipe tear resistance without heightening heat build-up so as to improve wear resistance by specifying the sulfur quantity in the outermost layer of a tread cap part, the thickness ratio of the outermost layer to the depth thickness and also the sulfur quantity in the inner layer of the tread cap part. CONSTITUTION:A tread 10 is formed in such a way that the sulfur quantity Ts (phr) in the outermost layer 12 of a cap part C formed together with a base part B is 0.5-1.0 and that the thickness ratio of the outermost layer 12 to the depth thickness 18 is 0.2-0.5 Ts+0.2. When the thickness of the tread part corresponding to the depth of the depth 16 is made the depth thickness 18, and the sulfur quantity in an inner layer adjacent to the outermost layer 12 is made Ns (phr), Ns-Ts is to be 0.4-1.2. High sipe tear resistance can be thereby secured without heightening heat build-up so as to improve wear resistance. |
