Patent ID: 8215357

Claim:
A pneumatic tire comprising a pair of bead portions, a pair of sidewall portions, a tread portion continuing to both the sidewall portions, a carcass toroidally extending between the pair of bead portions to reinforce these portions and comprised of one or more carcass plies, and a pair of side reinforcing rubber layers each having a crescent shape in section and disposed at an inside of the carcass in the sidewall portion, wherein the carcass ply is formed by covering plural reinforcing cords arranged in parallel with a coating rubber, and the reinforcing cord is a cord formed by twisting a filament bundle(s) including not less than 50% by mass of a polyketone fiber and satisfies conditions of the following equations (I) and (II): σ≧−0.01× E+ 1.2 (I) σ≧0.02 (II) [wherein σ is a heat shrinkage stress (cN/dtex) at 177° C. and E is an elastic modulus (cN/dtex) at 25° C. under a load of 49 N] and as the coating rubber is used a rubber composition having a loss tangent (tan δ) at 25° C. and 1% strain of less than 0.12 and a viscosity (G′), measured under conditions that a measurement temperature is 130° C., a strain is 100% and a frequency is 1 Hz, during the unvulcanization of not less than 50 MPa.