A hitch adapter comprises an inner square tube member for receiving Class-II 1.25'' drawbars and an outer U-channel member for plugging into a Class-III 2'' receiver. The inner square tube and outer U-channel members are welded together such that one wall of the inner square tube bridges the gap between the distal edges on opposite legs of the outer U-channel. One such leg of the outer U-channel is longer than the other and is positioned and aligned to protrude about 1/16'' beyond the adjacent outer corner of the inner square tube member. Such protrusion nests into the respective inside corner of the particular Class-III 2'' receiver it is mated to. The protrusion provides a camming action to take up any looseness and slack, and thereby eliminate wobble and rattle when installed by a user. A series of hitch pin holes allows a threaded hitch pin to pass through the adapter, a Class-II 1.25'' drawbar and a Class-III 2'' receiver. Threads inside the Class-II 1.25'' drawbar engage the hitch pin threads and provide the user a way to secure the whole assembly.