Run-flat tire

A run-flat tire comprising a tread portion, a pair of sidewall portions continuous on both sides of the tread portion, bead portions continuous on each sidewall portion, side reinforcing rubbers with crescent-like cross section disposed on the sidewall portions, a carcass formed of plies of radially arranged cords extending toroidally between the pair of bead portions, wherein:

• when the tire is mounted to a rim, and an internal pressure of 250 kPa or more is applied to the tire,
• in a case where a sectional width SW of the tire is less than 165 mm, a ratio of the sectional width SW to an outer diameter OD of the tire, SW/OD, is 0.26 or less;
• and
• in a case where the sectional width SW of the tire is 165 mm or more, the sectional width SW and the outer diameter OD of the tire satisfy a relation expression
• OD≧2.135×SW+282.3 (mm);
• the bead portions have bead cores, and further have bead fillers on a tire radial outer side of the bead cores;
• and
• when H1 is a tire radial maximum length of the side reinforcing rubber in a tire widthwise cross section in a reference state where the tire is mounted to a rim and filled with a predetermined internal pressure with no load applied thereon, and H2 is a length of a line segment connecting a tire radial outermost point of the bead filler and a tire radial outermost point of the bead core, H1 and H2 satisfy
• 1. 8≦H1/H2≦3.5.