RUN-FLAT TIRE

Provided is a run-flat tire in which the ride quality and the run-flat durability during normal running are highly combined. The tire is provided with a reinforcing cord layer covering the radial carcass at least from the belt end to the maximum width portion of the tire side portion; the cord constituting the reinforcing cord layer is nylon 66 cord, cellulose fiber cord, PET cord, PEN cord or aramid/nylon 66 hybrid cord, and has a cord angle of less than 10° with respect to the tire radius direction; and the elastic modulus of the cord pulled out from the tire at a temperature of 25°C under the conditions of a load of 3 N is not higher than 40 cN/dtex, and the thermal shrinkage stress à (cN/dtex) at a temperature of 177°C and the elastic modulus E (cN/dtex) at a temperature of 177°C under the conditions of a load of 10 N satisfy the following conditions: à + 0.025E ¥ 0.36,40 ¥ E ¥ 8, and Ã¥ 0.05