Abstract: An apparatus for reducing aerodynamic drag in a gap between a tractor and a trailer comprises a frame assembly and a panel assembly. The frame assembly includes a vertical member extending upwardly from a base, and two arms extending horizontally from the vertical member. The horizontal arms support a cylindrical member which rotates about its longitudinal axis and is biased by a biasing member so as to apply torque to the cylindrical member. The panel assembly is attached to the cylindrical member proximate a leading edge of the panel and includes a wheel offset from a trailing edge of the panel and gliding strips on an inner surface of the panel body. The inner surface of the panel body is in contact with a surface of the trailer proximate the wheel when the tractor is attached to and pulling the trailer.