Torsion axle v spring axle

Torsion axles (rubber dampened) don't have anywhere near the suspension travel a leaf sprung axle has. Not to mention if the trailer is not perfectly level when towing one axle will be loaded more than the other. I would take the heavier duty leaf spring system and add a rubber isolated equalizer system then you will have the best of both worlds. More suspension travel and smoother ride.

Much of the torsion travel is dictated by the length of the arms used. In the leaf spring world, longer springs typically allow for more travel.

One advantage of the torsion axle with swing arm is lack of "bump steer". When the lead wheel on one side of the trailer encounters a bump that the other side's lead wheel doesn't run over on irregular road surface, the wheel in it's "Up" travel is steered out. This is because the leaf spring, as it's arch is straightened from the bump, effectively gets longer from pivot point and axle attachment point. This may cause the trailer to steer slightly to one side or another and it's compounded when the second axle does the opposite as it encounters the same bump. How much this may contribute to overall trailer "sway" is dependent on other factors as well but it's part of the overall issue.

Torsion axles with swing arms hold the wheel in the same direction as it goes through it's entire "bump travel".

To me the torsion spring equipped trailer tracks far better than leaf springs with equalizers.

Dexter now has a series of axles that are approved for triple axle use. They are designated with "T" at the end of their axle size, such as 12T, 13T and 14T.