bighatnohorse - I got excited when I saw a sticker in the glove box that said - For Truck Campers -This is the cargo weight rating- I need to do more research on that number so that I can reconcile it in my head with the tire thing - the tire thing is so much easier I guess I was just worried that the trucks may have had different rating tires placed in the past 10-15 years. The tire trick is producing numbers that sound much more reasonable than the sticker.
So dually = tire rating x2
bjbear -yes I will weigh it eventually, but don't want to spend a lot of time inspecting vehicles just to get to the scale and find out they aren't going to work.