... . Axle Tube: One piece type, axle if fabricated from one steel tube without welding E. Air suspension system, most parts imported ... " or 3.5", welded or bolted in type. H. Fifth wheel. 2" or 3.5", forged or casting type. Can be ... dolly connection or full trailer M. Full series of Wheel & rim: Tube disc wheel 5.5-15, 5.5-16, 6.5 ... , 8.0-20, 8.5-20, 8.5-24 Tubeless disc wheel 6.0-17.5, 6.75-17.5, 7.5 ...