A pneumatic tire has a single carcass ply, at least one belt ply disposed radially outward of the carcass ply in a crown portion of the tire, and at least one insert located adjacent the carcass ply in a sidewall portion, the insert providing support for the tire load to enable the tire to operate in underinflated conditions. The carcass ply is comprised of at least one composite cord. The composite cord is formed of at least two first yarns twisted helically about at least one second yarn. The first yarns and the second yarn having different modulus of elasticity, the first yarns having a modulus greater than the modulus of the second yarn.