Patent ID: 7168470

Claim:
A pneumatic radial tire, comprising a carcass extending between bead portions, a belt layer arranged inside a tread portion and radially outside the carcass, and a band layer arranged outside the belt layer, the band layer comprising a band ply formed by winding spirally a belt-form ply including one or plural band cords being arranged and embedded in a topping rubber, the band cord being made of polyethylene naphthalate having a sectional area in a range of from 0.13 to 0.35 mm 2 and a 2% modulus of not less than 10000 N/mm 2 , wherein when the sectional area of the band cord is represented by S (unit: mm 2 ), the 2% modulus thereof is represented by M (unit: N/mm 2 ), and the band cord arrangement density per cm of the band ply is represented by D (unit: cord number/cm), the elongation resistance value K (unit: N′ cord number/cm) specified by the following equation is set within the range of 99 to 700 in the band ply: K=S×M×D/ 100 (1).