A method of building a sequence of tyres (2) different from each other, comprises generating a first deposition surface (22) by a first series of consecutive circumferential sectors (21). The first deposition surface is selected as a function of the type of a first tyre to be built. Each circumferential sector (21) of the first series is removably coupled to a central body (20) of a forming drum (16). The method further comprises 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 (22) of the forming drum (16), removing said at least one component from the forming drum (16) and replacing each circumferential sector (21) 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. The replacement comprises uncoupling each circumferential sector (21) of the first series from the central body and removably coupling each circumferential sector of the second series to the same central body (20).