My Haulmark two place enclosed snowmobile trailer has a trailing torsion bar axle and it doesn't bounce empty or loaded. It is a heavybuilt trailer though. Twin steel 8" I-beam frame rails, steel cargo box frame, aluminum skinned and plywood lined with a 3/4" plywood floor...heavy built! Probably close to a thousand pounds empty, so the wind doesn't seem to have it's way with it. That is the curse of any light, high-sided enclosed trailer, the wind, especially a cross-wind. If your intended cargo is low-profile, stick with the lowest profile enclosed trailer possible. I've seen some new aluminum low-profile U-Haul tailers that look pretty slick, I don't know who makes 'em though...