| 摘要 |
PURPOSE:To secure operation stability and wear-resistance and to improve performance on snow and ice by setting the pattern rigidity in the circumferential direction of a block and the pattern rigidity in the lateral direction of a tread pattern within a designated range. CONSTITUTION:When the pattern rigidity Ky in the circumferential direction of a pattern block 3 formed into a tread 2 and the pattern rigidity Kx (unit: kgf/mm) in the lateral direction of a tire are calculated according to the expression I, each rigidity is set in such a manner that Ky is 100-300, Kx is more than 150 and less than 350, and a difference Kx-Ky therebetween is Kx-Ky>50. The ratio SL/SS of the actual ground contact area SL of the tread 2 to the apparent ground contact area SS to which non-ground contact portion is added is set at 0.5-0.8. Further, the tensile elastic modulus E of the tread rubber is set at 120kgf/cm<2>-200kgf/cm<2> By this arrangement, performance on snow and ice can be improved without damaging operation stability and wear-resistance. |
