| 摘要 |
PURPOSE:To effectively prevent exfoliation of rubber at end parts of a belt layer by making the largest breadth of a belt layer reinforcing a crown part of a carcass ply layer larger than a tread grounding breadth and specifying the thickness of rubber adjacent to the end parts of the belt layer. CONSTITUTION:A radial tyre 1 for a heavy car consisting of reinforcement ply whose cord is arranged at about 90 deg. with respect to the tyre equator surface V-V' is equipped with a toroidal carcass ply layer 3 left and right ends of which are stopped at bead wires 2, a belt layer 4 reinforcing a crown part of said layer 3 and a tread rubber layer 5 arranged outside of the layer 4. In this case, the largest breadth BW of the belt layer 4 is made larger than a tread grounding breadth TW, and further, the smallest rubber thickness (b) between the belt layer end part BE of the biggest breadth and an outer wall 6 of the buttless part is set within 0.2-0.5 of the rubber thickness (a) on the tyre equator surface V-V'. |
