I posted the following on the Ranger board but thought maybe I might get a few more responses here. The one thing I should add to what I posted below is that I fill my tires to 50psi before each trip.
I own a 2007 619 Fisherman that sits on a dual axle trailer. I've owned the boat since new. The front axle was replaced, along with the tires, under warranty in the spring of 2009. The symptom at that time was severe inside tire wear. The tires are on a 5 year replacement plan, so 2 of the tires are 5 years old and 2 are 3 years old. While spending some time clean up the boat for my October trips I noticed that the inside tire treads on all 4 tires were worn pretty unevenly compared with the other sections of the tires. I've run Marathons since new and never had any problems with them and plan on replacing all of them next spring with the new Endurance tire from Goodyear. The boat has a 45 gallon gas tank and when full I'm sure it's adding around 300lbs to the boat and thus more weight for the trailer to handle. So as I scratch my head and wonder if i now need two new axles is it possible the trailer needs nothing more than alignment. I was under the impression that trailer tires cannot be aligned. I want to think that others have experience this same tire issue and wonder what was the cause was in your case and what did you do to correct the problem.
Thanks