Abstract: A cover is provided to protect a bicycle from exposure to environmental conditions during transport on a roof-top rack of automobile. Fasteners are used to secure the cover about bicycle. An aperture is located at the rear of the cover, i.e., the aperture opens in a direction opposite the forward motion of automobile as represented by arrow. As a result of a difference in air pressures between the interior and exterior of the cover, a pressure drop occurs at aperture which in turn creates a suctioning effect to inhibit undesirable buffeting and possible tearing of the cover.