Radial-ply tire having low rolling resistance

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