A pneumatic radial tire has a carcass structure, a belt structure, and a tread. The belt structure has at least two plies of reinforcing cords, the cords in the at least two plies being inclined at angles greater than 5.degree. relative to the tire centerline. The cords in the belt plies are inclined at equal but opposite directions relative to the tire centerline. The belt plies have a stiffness variation in the circumferential and meridional directions of the belt plies wherein the stiffness variation is in the range of 12 to 25% between a radially outermost belt ply and a radially innermost belt ply.