Abstract: Heavy goods vehicle tire, having a crown portion covered radially on the outside by a tread, this tread having at least two cut-outs, the central portion of the tread having a width Lc of between 35% and 70%, the crown portion comprising a reinforcement having at least two working layers having reinforcing elements, these reinforcing elements consisting of UHT-grade threads, having a mechanical breaking strength R satisfying the following relation: R?(4180?2130×D), where D is the diameter of the thread expressed in millimetres, this tread being formed of at least two layers of superimposed material, the material forming the first layer with a breaking elongation of more than 600% at a temperature of 60° C., this tread being such that, in the central portion, the cavity ratio per unit volume is not more than 10% and the surface cavity ratio as new is not more than 10%.