I had a similar problem years back with my Trailstar trailer. Tires wearing on the outside edge only - and wearing very quickly. Tire pressure was good, boat trailer is level, camber right on, etc. after a number of calls to BPS, where I bought the boat, they replaced the tires. Finally got Tracker to admit the tires supplied with the trailer were bad. Even the replacements wore the same way. Heck with BPS and Tracker. I went to a local tire dealer and picked up a good set of radial tires. Three years now and no sign of un-even wear. I keep mine filled to the recommendation is on my trailer - and that is 50 PSI Cold. I check them before each trip and periodically when the boat is not being used.