Abstract: A radial aircraft tire has a casing with a belt reinforcing structure overlying a carcass reinforced with radially extending cord reinforced plies and a tread. The tread has four main grooves extending circumferentially continuously around the tire defining five ribs. The main grooves include two inner main grooves disposed on each side of a central rib Y and two outer main grooves defining a pair of intermediate ribs between inner and outer main grooves and a pair of shoulder ribs, X, Z; in each shoulder region of said tire axially outward of an outer main groove. The invention teaches superior tread wear is achieved when the following relationships are fulfilled when the tread surface of the normally rated inflated tire under rated load contacts with a flat surface: 1. ( XA + XD ) + ( ZA + ZD ) ( XB + XC ) + ( ZB + ZC ) = 0.5 ? ? ? to ? ? ? 1.05 2. ( XA + XB + XC + XD ) + ( ZA + ZB + ZC + ZD ) TotalNetArea = 0.34 ? ? ? to ? ? ? 0.