| 摘要 |
PURPOSE:To improve the gripping power on hard road and the traction power on soft ground in a motocross tire which conforms to given effective area rate and given block height by making the block composed of inner and outer layer rubbers with respective required fixed properties. CONSTITUTION:In a pneumatic tire for a motorcycle, with a tread having effective ground contact area of 15-30% of its appararent ground contact area, with blocks 7 of which projection height (h) above skid base 8 is 10-18% of the tire height H, and with block type tread pattern which is applied to the portion near the maximum width position of a side wall 4, the block 7 is made to have a structure that 30-65% of apparent volume of the block 7 is made of an inner layer hard rubber having dynamic elastic modulus of more than 200kgf/ cm<2>, and its ground contact portion is covered by an outer layer rubber having dynamic elastic modulus equal to 0.4-0.85 times of that of the inner layer rubber and less than 200kgf/cm<2> and is more than 3mm. in gage thickness. By the above, it becomes possible to improve gripping power and traction and to prevent breakage of the block. |
