a removable wheel covering to improve the aerodynamic profile of a motor vehicle tire comprising means for fastening the wheel covering to a wheel rim , the rim having a first axis about which the rim is rotatable ; means for flexibly adhering the wheel covering to a tire side wall ; and an air engaging circular surface that is rotatable about the axis , that is convex with respect to the tire , and that has a diameter that is proximal to the diameter of the tire at the side wall .