A vehicle step tube comprising a one-piece elongated extrusion having a plurality of vertical ribs extending from the upper surface, the ribs define a plurality of channels between the ribs. The ribs may be relatively short in a step portion of the extrusion to form a step platform, and may be relatively tall in the flanking portions flanking the step portion. The ribs may further define transverse recesses in the step portion to enhance traction and aesthetics. A pair of end caps may be provided to cover the ends of the extrusion. The ends caps include openings aligned with the channels to allow fluid flow through the channels and the openings and into an environment.