The present invention relates to a method and an apparatus for producing tyres. The apparatus comprises a mixing extruder (1) including a suction pump (24) in fluid connection with an inner chamber (17) of the mixing extruder (1) at a sector of the mixing extruder (1) close to an extruder head (19), such a suction pump (24) being suitable to operate at a suction pressure (Pa) preferably lower than about 150 mbars. This suction pressure enables the processing ability features of the elastomeric compound, as well as the performances findable in a tyre obtained from semimanufactured products produced with said elastomeric compound, to be improved.