Shaft-hub connection, adapter and geared motor, wherein a shaft, in particular motor shaft, is introduced into a receptacle region (13) of a hub, in particular an adapter shaft (1), and is connected in a frictionally locking fashion, in particular connected by clamping, wherein the hub has three flattened portions, spaced apart from one another regularly in the circumferential direction, at least in one axial region, wherein a first screwed part (3), in particular a first preferably radially acting threaded pin (3), is screwed into a clamping ring (2) and presses onto a region of the hub in order to bring about the frictionally locking connection, in particular by clamping the clamping ring against the hub, wherein, in particular,, the region covers a circumferential angular region which is smaller than the angular distance in the circumferential direction between two flattened portions which are next to one another in the circumferential direction.