Patent ID: 6408909
Filing Date: 2002-06-25
Classification: B60C,Y10T

Abstract:
A pneumatic radial ply runflat passenger tire having a tread, two sidewalls, one or more plies extending from and wrapped about two annular bends and a belt structure located radially between the tread and the plies,the tread having a center rib and a pair of side ribs separated from the center rib by a circumferential decoupling groove and a circumferential second decoupling groove; the center rib having a first axial contour having a first radius, and the pair of side ribs each having a second axial contour sharing the same second radius; the tire characterized by; the first radius being larger than the second radius; the first axial contour intersecting the second axial contours nontangentially at first and second meeting points, each of which meeting points forms a circle around the tread that is on a plane that is parallel with a equatorial plane of the tire; the first and second decoupling grooves each having a pair of sides that are either zig-zag or sinusoidal and are suitably disposed and spaced from each other such that the circle of the first meeting point is axially between the pair of sides of the first decoupling groove, and the circle of the second meeting point is axially between the pair of sides of the second decoupling groove; and the sidewalls having at least a first ply reinforced with cords having a modulus of at least 10 GPa and a second ply reinforced with cords having a modulus greater than the modulus of the cords of the first ply, and an insert disposed in the sidewalls between the first and second plies.