PNEUMATIC RADIAL TIRES FOR PASSENGER CARS USED UNDER HIGH INTERNAL PRESSURE

摘要

A pneumatic radial tire for passenger cars used under a high internal pressure of 2.0-3.0 kg/cm2 is disclosed, which comprises a body reinforcement including in combination of a carcass composed of at least one rubberized ply containing organic fiber cords arranged in a substantially radial plane of the tire and wound around a bead core from the inside toward the outside thereof and a belt composed of at least two rubberized layers superimposed about a crown portion of the carcass, each of which containing high elasticity cords inclined at a relatively small angle with respect to the circumferential direction of the tire and the cords of these layers being crossed with each other, and further comprising sidewall rubbers disposed at both sides of the carcass and a tread rubber with a two layer structure composed of an under-tread rubber completely covering the outer surface of the belt and a top-tread rubber superimposed thereabout. In this tire, the undertread rubber has a modulus at 25% elongation of 2.0-8.0 k.g/cm2 and a dynamic modulus of 8.2-33.0 kg/cm2.