A pneumatic radial tire having an improved durability in the running on bad road is disclosed, which comprises a carcass composed of at least one rubberized cord ply containing cords arranged substantially perpendicular to the equatorial plane of the tire and a belt superimposed around the crown portion of the carcass and composed of at least two rubberized cord layers each containing cords inclined at a relatively small angle with respect to the equatorial plane of the tire, the cords of which being crossed with each other. In this tire, the outermost layer of the belt contains cords having a flexural rigidity lower than that of the remaining layer and arranged at an end count higher than that thereof.
