RADIALER LUFTREIFEN

摘要

A pneumatic radial tire wherein a carcass comprising plies of cords extending in a toroidal fashion between a pair of bead portions and radially arranged constitutes a framework of said tire, wherein a belt is disposed radially outwardly of said carcass, and wherein a belt reinforcing layer comprising organic fiber cords is provided radially outwardly of said belt, said pneumatic tire being characterized in that said organic fiber cords constituting said belt reinforcing layer are of folding-twist construction and have a twisting multiplier Nt set between 0.06 and 0.30 to thereby improve its high speed durability, said twist coefficient being defined by the expression (1): Nt = T x (0.139 x D/ rho )<1/2> x 10<-><3>, where T is the number of twists (per 10 cm), D is the total denier, rho is the specific gravity (g/cm<3>).