In an automotive road milling machine (1) for milling ground surfaces (3), with a machine frame (2), a milling drum (4) with a quick-change system arranged at the machine frame (2) in a drum housing (11), a driving device (6) for driving the milling drum (4), a reduction gear (8) arranged between the driving device (6) and the milling drum (4), where the milling drum (4) is arranged between drum housing walls (12,13) of the drum housing (11) running orthogonally to the axis of rotation of the milling drum (4), where the quick-change system is provided with a basic drum body (14) and at least one milling tube element (10) capable of being pushed onto the basic drum body (14), where the drum housing wall (13) opposite the drive-side drum housing wall (12) is easily removable for the quick exchange of alternatively usable milling tube elements (10), it is provided for the following features to be achieved: the housing (9) of the reduction gear (8) is attached to the machine frame (2) in a torsionally rigid fashion, inside the machine frame (2), between the driving device (6) and the drum housing wall (12) at the drum housing (11).