Abstract: A method and apparatus (10) is disclosed for covering a cavity (11) of a wheel of a long-haul tractor-trailer, truck or the like for decoration, streamlining, and/or advertising display. Such wheels have a face, a rim, the interior of the rim defining the cavity, a boss (30) on the rim having a relatively smaller diameter and spaced from the face. The disclosed method includes providing a device (10) comprising a generally flat cover portion sized to cover the outwardly facing opening of the wheel cavity, an opening through the device, and a releasable fastener (15) for selectively closing the opening through the device, and an attachment system (12) that is sized to extend axially across the boss of the wheel to the covered, accessing the attachment system through the opening, positioning the attachment system over the boss of the wheel by way of the opening, and closing the opening, such that the cover portion closes substantially all the outwardly facing opening of the wheel.