Run flat tire

A run flat tire comprising:

• a tread portion;
• a pair of sidewall portions connected to both sides of said tread portion;
• bead portions connected to each of said sidewall portions;
• a side-reinforcing rubber having a crescent-shaped cross section disposed in said sidewall portion;
• and
• a carcass straddling toroidally between a pair of said bead portions, the carcass having a carcass body portion, which is fastened to a bead core, and a carcass fold portion, which extends from the carcass body portion and is folded around the bead core;
• wherein,
• said side-reinforcing rubber-is a consists of only one low elastic portion and an other portion, the low elastic portion extending between an outer end and an inner end in the tire radial direction and having a lower elastic modulus than the other portion,
• said outer and inner ends of said low elastic portion are disposed along the carcass body portion and located in an area, in the tire radial direction, of 50% or more and 80% or less of the tire cross-sectional height from the bead baseline, in a reference condition with said run flat tire mounted on an applicable rim, filled with prescribed internal pressure, and unloaded,
• an elastic modulus of said low elastic portion is 80% or less of an elastic modulus of said other portion,
• when a maximum thickness of said low elastic portion, measured in the direction of a perpendicular line from said carcass down to a tire inner surface, is t1 and a thickness of said other portion, measured in the direction of said perpendicular line, is t2, the ratio t1/t2 is 0.2 or more and 3 or less,
• a tire maximum width in said reference condition is a center value or more and a upper limit or less of the tire maximum width associated with a given rim construction, and
• a tire maximum width position in said reference condition is located at the position, with a distance of more than 50% of the tire cross-sectional height, outward in the tire radial direction from the bead baseline.