Turn-up section and tire building drum comprising said turn-up section

A first drum half for together with a second drum half forming a tire building drum, wherein the first drum half comprises the turn-up section comprising a plurality of turn-up arms distributed circumferentially about a central axis (X) and an arm support configured for supporting said turn-up arms with respect to a base, wherein the turn-up arms are rotatable with respect to the arm support from an arms-down position towards an arms-up position in response to the movement of the arm support in an arm drive direction (D), wherein the arm support comprises a hinge seat configured for removably receiving the respective turn-up arm, wherein the respective turn-up arm is retained in the hinge seat by one or more biasing members, wherein the respective turn-up arm is removable from the hinge seat in a radial direction (R) with respect to the central axis (X) by counteracting the bias of the one or more biasing members, wherein each turn-up arm is provided with a cam surface that is configured for lifting the respective turn-up arm out of the respective hinge seat when the respective turnup arm is rotated radially outwards beyond the normal arms-up position.