Radial tire with high angle, low elongation plies and low angle, high elongation plies in belt

Claim 1

A tire, particularly for heavy and very heavy carrier vehicles traveling off the road, having a tread, a carcass reinforcement formed of at least one ply of radial wires or cables anchored to at least one bead ring in each bead and a tread reinforcement arranged radially outward of the carcass reinforcement and formed of at least three superimposed plies of wires or cables parallel in each ply and crossed from one ply to the next forming different angles less than 90° with the longitudinal direction of the tire, the carcass reinforcement having an equatorial zone of low meridian curvature connnected on both sides to the sidewalls by a transition zone of high meridian curvature, characterized by the fact that the tread reinforcement is formed of (a) at least one ply of elastic wires or cables which are parallel to each other in said ply and form an angle of between 5° and 15° with the longitudinal direction of the tire, said ply having an axial width less than that of the tread, and (b) two superimposed plies of wires or cables of very low elongation which are parallel to each other in each ply and crossed from one ply to the next forming angles of between 50° and 70° with the longitudinal direction of the tire; that ply of wires or cables of very low elongation which is closest to the carcass reinforcement has an axial width greater than the axial width of the tread and extends into said transition zone and is separated from the carcass reinforcement in said transition zone by a layer of rubber whose thickness increases axially in the direction away from said equatorial zone.