Disclosed is a run-flat tire that strikes an even higher degree of balance between run-flat durability and ride quality during normal driving situations. The run-flat tire is equipped with a reinforcing cord layer (5) that covers along a radial carcass (2) from at least a belt end to the section of a tire side section with maximum width. The cords that form the reinforcing cord layer are either nylon 66 cords, cellulose fiber cords, PET cords, PEN cords, or hybrid cords of an aramid and nylon 66, and are provided with a cord angle of less than 10° to the radial direction of the tire; wherein the elastic modulus at 25°C and under 3N load of a cord that has been pulled out from the tire is no more than 40 cN/dtex, and the heat-shrinkage stress (σ) at 177°C and the elastic modulus (E) at 177°C and under 10N load of the same satisfy the following conditions: σ+0.025E ≧ 0.36, 40 ≧ E ≧ 8, and σ ≧ 0.05.
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