Trailers are built using torsion or leaf spring axles. Unlike leaf spring axles that have curved metal leafs stacked on top of each other, torsion axles have a straightforward, attached construction with adjustable ride height and a rubberized suspension system. Four rubberized cords are inside the axle housing which handle suspension travel and shock absorption. As each wheel moves up and down, the rubber cords compress offering an even wheel suspension system for a smooth ride.
In addition, this provides more trailer rigidity since the axle is bolted to the trailer frame. The frame is stiff and this reduces flex in cross winds and on rough roads. Torsion axles are less likely to corrode as each torsion axle tube is galvanized inside and out and there is no metal-to-metal contact.