Pneumatic radial tires with stiffener rubber having hard and soft stiffener rubber members

摘要

A pneumatic radial tire comprises a carcass of at least one rubberized cord ply having a main carcass body and a turnup portion, and a stiffener rubber taperingly extending between the main carcass body and the turnup portion toward an end of the tread portion, wherein the stiffener rubber comprises a hard stiffener rubber member located near to the main carcass body and a soft stiffener rubber member located along the turnup portion over the hard stiffener rubber member, and the hard stiffener rubber member convexly projects toward the outside of the tire at a cross-section of the tire in a region between a normal line L_V and a line segment L_H, and a height of the hard stiffener rubber member from the outer surface of the main carcass body on a normal line L is maximum in a region from the line segment L_H toward the end of the tread portion.