To provide a run-flat radial tire having a comparatively large tire sectional height which improves run-flat durability.SOLUTION: A run-flat radial tire includes a carcass, a side reinforcement rubber which is provided on a tire side part and extends in a tire radial direction along an inner surface of the carcass, and a belt layer 16 that is provided on the outside in the tire radial direction of the carcass and is formed of a plurality of belt plys in which a plurality of cords arranged in parallel with each other are embedded in a coating rubber, where the belt layer 16 has a main crossing layer 16D having two layers of belt plys 16B and 16C with mutually different inclination angles to a tire equator surface of the cord and an outside layer (belt ply 16A) which is provided on the outside the tire radial direction than the main crossing layer 16D and has an absolute value of the inclination angle to the tire equator surface of the cord of 35° or more, and has a length in a tire width direction of 50% or more and less than 75% of the length in the tire width direction of the main crossing layer 16D, and the tire sectional height is 145 mm or more.SELECTED DRAWING: Figure 3
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