| 摘要 |
Provided is a run-flat tire which has an excellent run-flat performance and at the same time excels in high-speed straight running stability in the non-punctured state, a steering stability on both of a dry road surface and a wet road surface and a fuel efficient performance. A run-flat tire is provided wherein at least two crossing belt layers which are composed of rubberized steel cords and a tread rubber are disposed in the mentioned order, and wherein a reinforcing rubber is provided in the inside portion of carcass. The steel cords have a single-twisted structure or a core/single layer sheath structure with 6 to 10 steel wires having a wire diameter of 0.10 to 0.20 mm, the end count of the steel cords is not smaller than 40 cords/50 mm, the distance between the adjacent steel cords in the belt layer is not smaller than 0.3 mm, and the dynamic storage modulus E′ (MPa) at a temperature of 30° C. and the loss tangent tan δ at a temperature of 60° C. of the tread rubber respectively satisfy the relationships represented by the following formulae: 5.0≦̸E′ and 0.050≦̸tan δ≦̸0.240. |
