Patent ID: 7441575

Claim:
A pneumatic runflat tire having an equatorial plane (EP), a pair of opposing bead portions, a pair of opposing sidewalls, at least one carcass reinforcing plies, a sidewall insert axially inward of at least one of the carcass reinforcing plies in each sidewall portion, and a belt structure located radially outward of the carcass reinforcing plies, the tire being characterized by the bead portions being symmetrically distanced from the equatorial plane (EP) of the tire, and the tread on each side of the equatorial plane (EP) having different radius of curvature and different widths with the tread curvature on one side of the equatorial plane (EP) defined by continually decreasing radii of curvature, the widths being measured perpendicular to the equatorial plane (EP) to a line tangent to the maximum width of the belt structure the sidewall insert comprising a rubber composition, the rubber composition comprising a diene based elastomer and 10 to 100 parts by weight, per 100 parts by weight of elastomer, of a nanozeolite having a particle size of less than 1000 nm and a negative coefficient of thermal expansion over at least part of the temperature range of 0° C. to 200° C.