In a process for manufacturing, moulding and curing tires for vehicle wheels without a vulcanization bladder, many drawbacks can result from a direct contact between the green tire and the fluid under pressure admitted in order to create the necessary pressing of the elastomer material against the vulcanization mould walls. In accordance with the present invention, said drawbacks are avoided by including in the tire manufacturing process a step of treating the inner surface of the green tire in order to prevent the permeation of the fluid under pressure into the inside of the tire structure. Said treatment can be carried out by associating at least one layer of prevulcanized elastomer material with the inner surface of the green tire.