My father bought a used 3/4, long wheel base, diesel truck with a $2,000+ anti sway system (can't remember brand) to tow his 6,500lb TT. No brainer right? Surely he has twice the TV and equipment needed to tow this light weight TT?
After he got the truck home and was going over it he decided he wanted to get bigger tires to improve his unloaded mpg and after inspecting the tires that came on the truck he noticed they were load range C!
LOAD RANGE C ON A 3/4 TON DIESEL? The truck by itself likely exceeded the tire load rating and at 6 ply with weak sidewall strength it was an accident waiting to happen.
A lot of emphasis gets put on tongue weight and sway control for very gopod reason, but don't overlook those tires.