Patent ID: 6427743
Filing Date: 2002-08-06
Classification: B60C,Y10T

Abstract:
A pneumatic tire comprising:a tread portion, a pair of sidewall portions, a pair of bead portions each with a bead core therein, a carcass ply made of cords extending between the bead portions and turned up around the bead cores from the axially inside to the outside of the tire to form a turnup portion in each said bead portion and a main portion there between, a bead apex disposed between said main portion and the turnup portion in each said bead portion and tapering radially outwardly from the bead core to its radially outer end, at least one pair of an axially outer cord layer and an axially inner cord layer each extending radially outwardly from each bead portion, said axially outer cord layer terminating at a radial height not more than 50% of the section height of the tire, said axially inner cord layer extending radially outwardly beyond the radially outer end of said axially outer cord layer, a cord spacing between said axially outer cord layer and said axially inner cord layer decreasing radially inwardly from the radially outer end of the axially outer cord layer so that a minimum value (tmin) thereof is in the range of from 0.15 to 7.0 times the diameter of the carcass cords, said axially outer cord layer being the turnup portion of the carcass ply, the turnup portion sandwiched between an axially inner insulation rubber and an axially outer insulation rubber, each of the axially inner insulation rubber and axially outer insulation rubber having a 100% modulus higher than that of a sidewall rubber disposed axially outside the axially outer insulation rubber, and the 100% modulus of the axially outer insulation rubber being higher than the 100% modulus of the axially inner insulation rubber.