Abstract: A structure and method for securing an aerodynamic cover to a wheel of a roadway vehicle comprises fitting keyhole openings in a base plate or sectors thereof about at least some of the lug nuts holding the wheel to the hub of the vehicle axle, and rotating the base plate to engage portions thereof beneath or behind the lug nut heads or flanges, A locking bar is attached to the base plate or one of the sectors to prevent reverse rotation thereof. The wheel cover is placed over the wheel, engaged at the cover's periphery against the rim of the wheel, and attached to upstanding brackets carried by the base plate or sectors.