Who should he sue? Some guy sold a car for $250, you can pretty much expect it to need some work/new parts before long. A mechanic pointed out the size difference in his tires.
A part broke (cheep tire), which in turn broke other stuff. Sh*t happens. It wasn't anyone's fault, though it does suck.
The OP gave the best advice. When something changes (vibration) pull over and check it out. Just last week that's how I noticed one of my front wheels had somehow gotten loose, which could have been very expensive if it had fallen off.
EDIT: on the subject of filling to maximum, it was probably a non-factor in your tire failure. Personally I don't go to max for better wear characteristics and ride.
__________________
|