Abstract: A tread for a pneumatic tire featuring generally zig-zag ribs defined by wide grooves. Circumferentially extending slots in the ribs are located near the wide grooves. The circumferentially extending slots define an edge zone between the slots and the nearest wide groove and a primary-load zone on the opposite side of the slot. Located in the edge zone there is means for reducing the unit tread pressure in the edge zone as compared to such pressure in the primary-load zone. The circumferential slots together with the means for reducing the unit tread pressure act to provide a breakwater against the spread of irregular wear known as "river wear".

Abstract: A pneumatic tire has first and second carcass plies. The first carcass ply has outer portions that are folded around axially spaced annular tensile members (bead cores) and terminate under a belt structure. A pair of shoulder plies are disposed in the upper sidewalls of the tire between the central portion of the second carcass ply and the lateral edge portions of the first carcass ply. A pair of lower sidewall plies are disposed in the lower sidewalls, and are folded around their respective annular tensile members, terminating radially inwardly of the axially widest part of the tire.