I just *HAVE* to respond to 'UNISCAPER'. You referred to 'torque bar' axles. I'm assuming you mean a rubber torsion spring axle? I thought you might like to know for future reference that Dexter Axle makes what they call a 'Torflex' axle. I don't know if this is what you've used in the past or not. (There are quite a few manufacturers making torsion axles now) Dexter however, gives an incredible warranty with their products and they stand behind them like no one else I've ever dealt with. The Torflex axles should NEVER become loose in ANY way, much less enough so that they create abnormal tire wear! If these are what you've used, PLEASE call Dexter. They WILL make it right!
I build trailers for a living, and while I don't do many light trailers such as those being discussed here, I have about 200 on the road now that I have built since 1993, and I have never had one come back for the problem you stated. (probably 95% of them have the Torflex axle)
Hope this has helped in some way.