A tire having a radial carcass reinforcement, including at least one layer of reinforcing elements, said tire comprising a crown reinforcement, which is itself covered radially with a tread, said tread being joined to two beads via two sidewalls, wherein at least 85% of the reinforcing elements of at least one layer of the carcass reinforcement are non-wrapped metal cords having in what is called the permeability test a flow rate of less than 20 cm3/min, and in that at least 5% of the reinforcing elements of said at least one layer of the carcass reinforcement are cords comprising at least one strand consisting of textile multifilament yarns.