A tire manufacturing method and plant, in which: a naked casing without any tread is provided; a winding system winds a green rubber cushion and a pre-cured tread strip about the surface of the casing; and a curing system cures the green rubber cushion inserted within the tire between the casing and the tread strip. In the curing system the tire is inserted inside a sealed curing chamber which is pressurized over the ambient pressure and is inflated. The curing chamber is delimited by two opposite base walls having a circular shape and by a lateral wall having a cylindrical shape and connecting the two base walls one to the other. The lateral wall is moved axially, by means of a displacing device, to and from the two base walls respectively to close and to open the curing chamber.