Re: tire ware !
Um, not to be simple, but check that all tires are the same, and have the same outside diameter. I picked up an old boat last year, dragged it home and rolled it into the garage for a closer inspection. Well, heck, one tire was almost completely bald on the inside....but pretty much new on the outside. I hummed and hawed, checked the axle to make sure it was square to the tongue, checked the frame to make sure it wasn't twisted on jack stands, checked to make sure the boat was centered on the trailer, and of course checked air pressure. Huh, no problems here...time go get a beer and think this one over. Standing on my driveway I noticed the boat sat lower on one side then the other, I began to worry that the boat was sagging on one side, becuase it was most certainly center. Well after much panic, it occured that I should check the tires again. Sure enough the right tire was two inches smaller then the left, and the spare was 1 inch larger! Went out to Princess Auto, got 3 new tires with rims...and voila..no more uneven tire wear!
Different tire manufacturers, even with the same size stamp, can vary slightly in outside diameter.
Ian