HEAVY DUTY PNEUMATIC RADIAL TIRE

摘要

A pneumatic radial tire for a heavy duty vehicle, in which durability of belts is improved. The pneumatic radial tire has a pair of bead sections in which bead cores are embedded individually, and also has a radial carcass layer (1) extending from one bead section to the other and folded back around the bead core of the other bead section from the inside to the outside. At least six belt layers are formed on the outside of the radial carcass layer (1). The radial tire satisfies the relation of W₅₆ > W₃₄ > W₁₂, where W₁₂ is the maximum width of the first and second belts (2a) of the belt layer (2), W₃₄is the maximum width of the third and fourth belts (2b), and W₅₆ is the maximum width of the fifth and sixth belts (2c). The radial tire also satisfies the relation of 1 > D₁₂/D₃₄ > 0.6, where D₁₂ is_{the diameter of the cords of the first and second belts and the D34 is the diameter of the cords of the third and fourth belts. The steel cord of each belt layer is formed in a double twisted structure in which two to ten cables each formed by twisting multiple steel filaments around each other are further twisted around each other.}