Safety tire having defined carcass curvature from the point of maximum width to the bead

Claim 1

A pneumatic tire having a tread portion, a pair of bead portions, a pair of sidewall portions therebetween, a pair of bead cores one disposed in each bead portion, a carcass extending between said bead portion through said sidewall portions and said tread portion and turned up in both edges around said bead cores to be secured thereto and to form carcass turnup portions and a carcass main portion therebetween, a tread disposed on said carcass, a belt disposed between said tread and said carcass and having cords laid at a relatively small angle to the tire equator, and a pair of bead apexes one disposed between said carcass main portion and each of said carcass turnup portions, wherein, in a state that the tire is assembled on a specified rim and inflated to a specified pressure, the aspect ratio of the tire defined as the tire sectional height/the tire maximum width is not more than 80%, the axial width WT of said tread is greater than the maximum width WC of the carcass, each edge of said tread is positioned at a height within a range 50 to 100% of the sectional height HC of said carcass, said carcass being provided on each side of the tire equator with a convex arc part with a radius R1 and a concave arc part with a radius R2, said arc parts smoothly contacting each other at an inflection point therebetween, said convex arc part having the center of curvature positioned inside the tire and extending radially inwardly from the point of the maximum width WC of said carcass to said inflection point, said concave arc part having its center of curvature positioned outside the tire and extending radially inwardly from said inflection point to the vicinity of a contact point at which the carcass contacts with the bead core, the radius R2 of said concave arc part is greater than the radius R1 of said convex arc part, and at least one of said bead portions being provided with a radially inwardly extending toe located axially inside said bead core to be inserted into an annular groove formed on the rim, and a groove located axially outside said toe to be fitted into a hump formed on the rim.