Universal aerodynamic wheel cover

An adapter assembly that allows a wheel cover to be attached to a wheel has an insert, a plug, a key and a wrench. The insert attaches through a hole in the wheel cover and has prongs that lock behind a cap lip of the wheel. The plug is screwed into the insert via the wrench, and plug threads push out on the prongs, securing them behind the cap lip. The key is inserted into a locking space between the outer surface of the plug and the inner surface of the insert.