RUN FLAT TIRE

We provide a run flat tire capable of ensuring high resistance to coming off of a bead portion from a rim in run flat running, while maintaining high durability of a side-reinforcing rubber. Specifically, a run flat tire, has a tread portion, a pair of sidewall portions continuous with respective sides of the tread portion, bead portions continuous with the respective sidewall portions, bead cores each embedded in the corresponding bead portion, and a side-reinforcing rubber having a crescent-shaped cross section and provided in each sidewall portion, wherein in a cross section in the tire width direction thereof: diameter of an annular inner end in the tire radial direction of the bead core is larger by 3.0-4.5 mm than rim diameter of a prescribed rim; and diameter of a circle collectively formed by the bead heal point is smaller by 1.7-2.9 mm than the rim diameter of the prescribed rim.