This discussion of torsion axles raises the question of whether it is prudent to put new torsion axles on an older trailer that exceed the GVW rating of the trailer. Let's say the trailer is rated at 5,200lbs max and it has two Dexter torsion axles. If one never intends to exceed the rated weight of the trailer, does it make sense to install 2 new axles that have a much higher load rating combined than the trailer's gross weight rating? I always had the impression the higher rated axles are "stiffer" than lower rated ones and that they can be "overkill" and actually cause more damage to a trailer vs ones that are more closely matched to the gross weight capacity of the trailer. Does that concept apply to torsion axles?
This is a good question. An example is the Xplore X22 with torsion suspension. The trailer weighs just about 5,300 lbs empty, but the tandem axles are rated for 5,000 lbs each. It is stiff riding. On the highway, that is a desirable trait as it doesn't lean on turns and is quite stable. But off road, it can be too rough. Answer: Air down. When aired down, you actually get several more inches of travel with a softer suspension. It is designed that way and works well. With the hydraulic adjustable torsion suspension system, you can adjust ride height, but not stiffness, or the ratio of compression to top-out travel. This means you could add ride height and still be near the suspension stops. The ride height is independend of the suspension travel.
The Cruisemaster swingarm system on the X195 and Roamer 1 have ride height adjustment with air. They seem to ride pretty well with a reasonable compromise on stiffness. You can't adjust the stiffness, but you can add more air to carry the load at a good point in the suspension travel, so you get proper suspension at various overall weights. They also seem to have good shocks with lots of damping. And Cruisemaster offers a sway bar option that should help with cornering, if needed.
Everyone should remember that torsion is independent, and swing arm is independent, but they are not the same. The torsion gets its spring action by twisting an axle shaft inside a tube to crush rubber strips, and no shocks Swing arms us springs made of coiled wire, air bags or rubber donuts that get squeezed as the swing arm travels upward. Swing arm systems use shocks. Swing arm systems have alignment adjustments and torsion doesn't. it is also important to note that swing arm and torsion systems should be towed level because they have no equalizers like leaf spring systems do. This makes the tandem tires carry equal weight and may help stability. Leaf spring suspension is fine for a dump trailer, but I have no interest in it for a travel trailer.
