PURPOSE: To obtain the comfortable riding of a car and improve its durability, by forming a carcass with a rubberized cord layer comprising a ply cord consisting of polyester of low polymerization degree with a prescribed component and a coating rubber consisting of a prescribed composite of rubber.

CONSTITUTION: A carass 5 of a radial tire 1 is formed into a rubberized cord layer by the conventional method from a ply cord, consisting of polyester of low polymerization degree mainly composed of polyethylene terephthalate with limiting viscosity η=0.45W0.8 (measured by orthochlorate phenol as solvent) at measuremet temperature 25°C, and a coating rubber, consisting of a rubber composite with swelling reticulate concentration νs=25×10-5W60×10-5mol/g at not more than 85wt% natural rubber. In this way, the radial tire 1 can obtain its quality of comfortable riding, rolling resistance, crack resistance at its ply end part, better holding rate of exfoliation resistance and cord strength.