Terry similar thing happened to us.. Must have tweaked the axle down here before a trip to Atikokan. Got there noticed really abnormal wear on the tires, didn't really clue into it to be honest, I thought maybe the tires were messed up. Finally had a brain fart just outside of the Sault on 17, pulled over did some measurements and we were a 1/4in out. Made it just south of Parry Sound before the tire blew taking out the plastic fender and marker light with it. Luckily I had CAA + RV, got the boat on a flat bed and back to Coldwater. Pulled the axle brought it into a shop and had it straightened.
I'm a lot more cautious when loading/unloading the boat now, it didn't take much to bend that axle when putting the boat in (high sided it on a rock at one of the launches we use all the time)..