Pneumatic radial tires with at least two monofilament cord belt layers

In a pneumatic radial tire comprising an innerliner, a carcass toroidally extending between a pair of bead portions and externally contacting with the innerliner, a belt arranged at an outer circumference side of a crown portion of the carcass, one or more cap layers covering the belt over substantially a full width thereof, and a tread arranged at an outer circumference side of the cap layer, an improvement wherein the belt is comprised of at least two belt layers each formed by covering metal monofilament cords or organic fiber monofilament cords with a coating rubber, and a rubber gauge between the monofilament cords located in the adjacent belt layers is made 1.5-5 times of a diameter of the monofilament cord,

• wherein each belt layer is constituted by arranging a plurality of cord groups, each of which are comprised of plural monofilament cords arranged side-by-side, in parallel and spaced apart with respect to each other,
• wherein the cords of the at least two belt layers are crossed with each other,
• wherein the carcass is comprised of at least one carcass ply containing polyethylene naphthalate cords therein, and
• wherein the cap layer contains at least one polyethylene naphthalate cord extending substantially in a circumferential direction of the tire.