Abstract: A tire building drum (10) has a central shaft (13) and a pair of end drum assemblies (12) mounted for axial movement along the shaft. The end drum assemblies (12) include a main sleeve (19) slideable on the shaft (13), and an annular housing (24) mounted on the sleeve to form an annular chamber (32) surrounding the sleeve (19) which houses an annular piston (31). There is an annular expansion means (bead seating segments) (27) mounted on the housing (24) which are moved radially by a ramp means (35) attached to the piston (31). This ramp means (35) have a cam surface (29) thereon comprising an inclined radially outer portion (29a) and a convex arcuate radially inner portion (29b). Further, the end drum assemblies have annular bladders (39), (41), (42), and (44) thereon that each have solid annular lip portions (51, 52) (61, 62), (63), (64 ) respectively, by which they are secured to the end drum assemblies.