A device for mounting a pneumatic tire onto a vehicle wheel rim comprises a handling robot, including a robot hand (7), which is movable about a plurality of axes and comprises a rotationally drivable flange (8) and a gripper (2) attached thereto, the gripper including a base element (10) and at least two gripper arms (15) which are movable radially relative to the centre axis of the gripper (2). The gripper arms (15) are coupled to a synchronization device, which synchronizes the radial movement of the gripper arms (15) and includes a disc (23), mounted on the base element (10) of the gripper (2) so as to be rotatable about the centre axis of the gripper and rotationally drivable via a motor, and coupling members (25) fixed to the disc (23) and the gripper arms (15) via hinged joints (26,27) in such a way that a rotation of the disc (23) produces a synchronous radial movement of the gripper arms (15).