RUBBER PRODUCT REINFORCING STEEL CORD, RUBBER AND STEEL CORD COMPOSITE MATERIAL, RADIAL TIRE, MOTOR CYCLE RADIAL TIRE AND TIRE

The durability is improved by using as a carcass ply cord or a belt cord of a tire a cord formed by twisting plural steel filaments having a tensile strength of not less than 2700 N/mm, and a total elongation at break of the cord of 3.0-7.0% without sacrificing the excellent ride comfort.