Whoa! something is bigtime out of whack! caster, camber, toe in or something like that... looks like more than just riding on the inside a bit. Is the tread cupped or anything?
The way I see the picture. it looks like there is too much pressure in the tire. I have a utility trailer that did the same thing, I replaced the tires, set the pressure correctly and have not had a problem since. And the utility trailer also had torsion axles.