A tire having a radial carcass reinforcement, composed of at least one layer of metal reinforcing elements, the said tire comprising a crown reinforcement, itself topped radially by a tread, the said tread being joined to two beads via two sidewalls. The metal reinforcing elements of at least one layer of the carcass reinforcement are cords exhibiting, in the permeability test, a flow rate of less than 20 cm.sup.3/min and at least one layer of the carcass reinforcement is provided, on at least one face, with textile threads exhibiting, in the permeability test, a flow rate of between 1 and 3 cm.sup.3/min.