| 摘要 |
PURPOSE:To reduce a strain at the ends of a belt without the rigidity of the belt being lowered in an off-road running heavy-duty tire, by providing a maximum width first main base layer and a narrow second base layer outside of the former among belt layers and by setting the widthwise step amounts of both base layers and the cord crossing angles between both base layers to predetermined values. CONSTITUTION:A first main base layer 22 having a maximum width and a second main base layer 23 having a width narrower than that of the first main base layer 22 and being laid radially outside of the same are provided among belt layers 21-24. Further, the widthwise step widths W of both first and second main base layers satisfy the equation I. Further, the crossing angle alpham between the cords in the first main base layer 22 and the cords in the second main base layer 23 is set to be greater than 32 deg. but less than 52 deg.. With this arrangement, it is possible to reduce strain at the ends of the belt without the belt rigidity being lowered.
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