Patent ID: 7918259

Claim:
A pneumatic tire comprising: a pair of bead portions; a pair of sidewall portions; a tread portion continuing to both of the sidewall portions; a carcass toroidally extending between the pair of bead portions and reinforcing the bead portions; a belt portion disposed on a crown portion of the carcass outward in a radial direction of the tire and including at least two belt layers; and a reinforcing layer formed by spirally winding a strip-shaped triaxial fabric or triaxial fabric-rubber composite having a width W in a circumferential direction of the tire a plurality of times, the reinforcing layer disposed at one or more of the bead portion, the sidewall portion and the belt portion, and the width W in mm of the strip-shaped triaxial fabric or triaxial fabric-rubber composite satisfies a relation of the following formula (I): W≧ 2/3×3 1/2 ×(2 b/a+d ) (I) wherein d=4×(D/(πp)) 1/2 ×10 −2 , D is a thickness in total dtex of cord constituting the triaxial fabric, p is a density in g/cm 3 of the cord constituting the triaxial fabric, and a is weaving density in cords/b mm in one axis constituting the three axes, and wherein the reinforcing layer is formed by spirally winding the strip-shaped triaxial fabric or triaxial fabric-rubber composite in the same plane the plurality of times.