Run-flat tire and method for mounting the same on four-wheeled vehicle

A run-flat tire comprising:

• a carcass extending between bead cores each disposed in a first bead portion and a second bead portion, through a tread portion and sidewall portions,
• a pair of side reinforcing rubber layers made of rubber having a high hardness, and each having a crescent cross-sectional shape and disposed axially inside the carcass in each sidewall portion, and
• a pair of sidewall rubber components each disposed axially outside the carcass in each sidewall portion in such a manner that the sidewall rubber components are directly adjacent to the carcass and form part of the outer surface of the tire,
• wherein the side reinforcing rubber layers comprise a first side reinforcing rubber layer disposed in the side of the first bead portion, and a second side reinforcing rubber layer disposed in the side of the second bead portion,
• wherein the sidewall rubber components comprise a first sidewall rubber component disposed in the side of the first bead portion, and a second sidewall rubber component disposed in the side of the second bead portion,
• wherein at a tire maximum-width position in a tire cross section including a tire axis under a standard condition in which the tire is mounted on a standard rim and is inflated to a standard pressure, but no tire load is loaded, the first side reinforcing rubber layer has a thickness B1 greater than a thickness B2 of the second side reinforcing rubber layer, and the first sidewall rubber component has a thickness A1 smaller than a thickness A2 of the second sidewall rubber component, and
• wherein the respective thicknesses A1, A2, B1 and B2 satisfy the following relationships:
• 1.4≦A2/A1≦2.0;
• and
• 1.15≦B1/B2≦1.4.