Originally Posted by dustman_stx
I don't think I'd go that far. They make 4500 and 5500 andů.. for a reason.
Around here it's at least enough to pull anything that you can legally pull with a standard Class G license. Max towed vehicle in Ontario is 4600 kg (10141.3 lbs). Max combined weight is 11000 kg (24250.849 lbs).
There's provisions for fivers to go over that 4600 kg, as long as the GVWR of the truck is under 6000 kg (13227.74 lbs) but still subject to the max 11000 kg combined weight limit.
So, given the Ram dually's are between 7-8k lbs, you'd be looking at max trailer in the 16-17k lbs range (when loaded).
Again, that'd only be here in Ontario. No idea what the local laws are for his state.