Belt drum (1), particularly for shaping a belt layer and/or a tread layer or another tyre component provided with metal parts and the like into a circumferential whole, wherein the drum is rotatable about a centre line, comprising a number of support members (2) having a rigid support surface for the tyre component and situated at the circumference of the drum, wherein considered in a cross-sectional plane containing the centre line, the support members comprise middle support sections (7) and side support sections (8a, 8b) movably connected thereto, wherein the middle sections of the supportmembers are moveable by first movement means (11, 12) between a first position, in which the respective support member forms a support surface that is parallel to the centre line, and at least one second position, in which a substantially convex support surface is formed by the respective support member, wherein the fBelt drum, particularly for shaping a belt layer and/or a tread layer or anothertyre component provided with metal parts and the like into a circumferential whole, wherein the drum is rotatable about a centre line, comprising a number of support members having a rigid support surface for the tyre component and situated at the circumference of the drum, wherein considered in a cross-sectional plane containing the centre line, the support members comprise middle support sections and side support members are moveable by first movement means between a first position, in which the respective support member forms a support surface that is parallel to the centre line, and at least one second position, in which a substantially convex support surface is formed by the respective support member, wherein the first movement means are connected to the middle support sections in order to at least keep them parallel to the centre line in at least the one second position.