Radial-ply tire having low rolling resistance

摘要

A pneutmatic radial-ply tire in which the rubber portion of at least one of a carcass ply and an undertread constituting the tire is made of a rubber which has a viscoelastic property of loss tangent, tan delta , of 0.2 or lower (tan delta /=120 kg/cm2), so that the rolling resistance of the tire is reduced without being accompanied by degradation of braking performance, control stability, comfortableness and wear resistance of the tire.