Tread and heavy duty tire

Claim 1

A tread for a non-driving axle tire for transport vehicles, the tire comprising a tread, two sidewalls and two beads, a radial carcass reinforcement and a tread reinforcement formed of at least two plies of wires or cables parallel in each ply and crossed from one ply to the next, characterized by the fact that the tread comprises in each of its two lateral zones a narrow, substantially circular circumferential groove defining a lateral rib, said narrow groove having a width of between 0.5% and 4% of the width of the tread and said lateral rib having a sloping shoulder, the meridian profile of the lateral rib being substantially parallel to and inward of the meridian profile of the geometrical envelope of the principal median zone of the tread, said principal median zone having a sharp, non-rounded edge where it intersects the tread surface, the sharp edge being maintained during the life of the tire by the lateral rib, the width of the lateral rib at its crown being at most equal to the maximum depth of the narrow groove, and the difference in level between the meridian profile of the lateral rib and the meridian profile of the geometrical envelope of the principal median zone of the tread is such that under normal conditions of travel both the lateral rib and the principal median zone are in contact with the ground and the ground contact pressure of the former is less than the ground contact pressure of the latter, whereby said lateral rib and principal median zone wear at rates resulting in the maintenance of said difference in level during the life of the tire.