A method of building a sequence of tyres different from each other, comprising: - generating a first deposition surface by a first series of consecutive circumferential sectors, said first deposition surface being selected as a function of the type of a first tyre to be built; each circumferential sector of the first series being removably coupled to a central body of a forming drum; - manufacturing at least one component (3; 8; 8a, 8b) of said at least one first tyre by deposition of said at least one component at a radially external position to said first deposition surface of the forming drum; - removing said at least one component from the forming drum; - replacing each circumferential sector of the first series with a circumferential sector of a second series for generating a second deposition surface selected as a function of the type of a second tyre to be built which is different from said first tyre; - said replacement comprising uncoupling each circumferential sector of the first series from the central body and removably coupling each circumferential sector of the second series to the same central body, - modifying the radial position of the circumferential sectors coupled to the central body before manufacturing at least one component of said at least one first tyre, by translating the circumferential sectors from a first diameter in which said first deposition surface is generated to a second diameter greater than said first diameter, - modifying the radial position of the circumferential sectors coupled to the central body before replacing each circumferential sector of the first series with a circumferential sector of the second series by translating the circumferential sectors from said second diameter to a third diameter smaller than said second diameter. - generating a first deposition surface by a first series of consecutive circumferential sectors, said first deposition surface being selected as a function of the type of a first tyre to be built; each circumferential sector of the first series being removably coupled to a central body of a forming drum; - manufacturing at least one component (3; 8; 8a, 8b) of said at least one first tyre by deposition of said at least one component at a radially external position to said first deposition surface of the forming drum; - removing said at least one component from the forming drum; - replacing each circumferential sector of the first series with a circumferential sector of a second series for generating a second deposition surface selected as a function of the type of a second tyre to be built which is different from said first tyre; - said replacement comprising uncoupling each circumferential sector of the first series from the central body and removably coupling each circumferential sector of the second series to the same central body, - modifying the radial position of the circumferential sectors coupled to the central body before manufacturing at least one component of said at least one first tyre, by translating the circumferential sectors from a first diameter in which said first deposition surface is generated to a second diameter greater than said first diameter, - modifying the radial position of the circumferential sectors coupled to the central body before replacing each circumferential sector of the first series with a circumferential sector of the second series by translating the circumferential sectors from said second diameter to a third diameter smaller than said second diameter.