Two things that I've been told and/or read about torsion axles:
1. They provide a smoother ride and are better for critters.
2. Tires wear better (more evenly) with sprung axles.
Are either of those statements not true?
All of our horse and cattle trailers have torsion axles and all of our flatbeds (gooseneck and bumper bull) have leaf springs.
The leaf sprung trailers handle weight better off-road as the hangers in between pivot to distribute the weight better between the axles.
The torsion axles allow for a lower deck height, but they do have a more pronounced empty "bounce" to them.
I don't see an appreciable difference in tire wear between the two, most of your damage is done while turning on hard surfaces and they're both going to slide the tires.
As far as tires go, I've had the best luck with Carlisle radial trailer tires on the lighter stuff (10k gross and below) and BFG Commercial T/A Radial truck tires on the heavier trailers. I just picked up 8 of the latter last night to put on a dual tandem gooseneck flatbed. Had to replace the set of Coopers that came on it, 5 of the original 8 had experienced tread separations while driving and two more were starting to oval. The tires had 50% treadlife remaining and there are other instances online of that particular Cooper tire giving other people the same problem, yet Cooper refused to talk with me about the tires. Needless to say, they just lost a customer for life.
