Patent ID: 6695025
Filing Date: 2004-02-24
Classification: B60C,D07B,Y10S,Y10T

Abstract:
A pneumatic radial ply runflat tire having a tread, two inextensible annular beads, a carcass comprising a radial ply structure having at least an axially inwardmost ply and an axially outwardmost ply, a belt structure located between the tread and the radial play structure, an inner liner, and two sidewalls each being reinforced by at least one wedge insert, the tire being characterized by:the axially inwardmost ply and the axially outwardmost ply being separated by the wedge insert in each sidewall; the axially inwardmost ply is reinforced by reinforcing cords having a substantially constant modulus of elasticity; and the axially outwardmost ply is reinforced by reinforcing cords having a modulus of elasticity that varies with strain, wherein said reinforcing cords in the axially outwardmost ply are constructed of multiple cords having different moduli of elasticity that operate within their respective elastic ranges during all conditions of operation of the tire.