| 摘要 |
PURPOSE:To prevent generation and growth of cracks from the bottoms of sipes by forming a tread rubber with two layers of a wear resistant rubber layer and a crack grow resistant rubber layer while specifying the cut depth of sipes in the crack grow resistant rubber layer. CONSTITUTION:A tire is provided with numerous sipes 4 formed in the tread part 3 having numerous ribs 2 divided by numerous main grooves 1 in peripheral direction while both ends of respective sipes 4 are opened to buttress parts 5. In the above mentioned constitution, a tread rubber 6 for forming the tread part 3 is formed with a wear resistant rubber layer 7 positioned on the surface side of the tread part 3 and a crack grow resistant rubber layer 8 positioned on at least side end parts of the tread part 3 and stuck to a belt 9. The cut depth of respective sipes 4 mentioned above in the crack grow resistant rubber layer 8 is set 10% or more of full depthes of respective sipes 4. Generation and growth of cracks from the bottoms of respective sipes are prevented thereby. |
