Heavy-duty pneumatic radial tire

Abstract

A heavy-duty radial tire having a belt layer comprising at least four metallic cord layers of first, second, third, and fourth belts in that order from the carcass layer towards the tread. The first belt has a cord angle of 40.degree. to 75.degree. relative to the circumferential direction of the tire and is split into left and right portions provided on left and right shoulder portions, respectively, so as to provide a space in the central region of a crown portion provided with either at least one organic fiber cord layer having a total tensile strength per unit width of at least 240 kgf/cm and a cord angle of 0.degree. to 10.degree. or an inextensible fiber cord layer having a two-layer structure wherein the sum of the tensile moduli per unit width in the initial tension of all the cords is at least 1.3.times.10.sup.3 kgf/cm, the cord angle is larger than 0.degree. and two layers in the two-layer structure cross each other at an absolute angle smaller than the cord angle of the second and third belts. The second belt comprises cords provided at a cord angle of 22.degree. to 30.degree.. The third belt comprises cords crossing the cords constituting the second belt and provided at a cord angle of 10.degree. to 16.degree.. The fourth belt comprises cords provided at a cord angle of at least 18.degree..