It all comes down to whether you go with Ratings, a little over on Trucks GVWR and under the others OR just hook up and go!
Personally I pay attention to Tire Ratings/Loading.
What the ole biscut said. My F 250 came with 17 inch tires. if I would have had an accurate crystal ball, I would probably went with an F 350 SRW. Last winter i had one of those General Grabbers separate on me. i just weighed the thing again and am 530 lbs under the max on each tire. Just got back from the tire shop yesterday and put two Firestone Transforce on the back for the hey of it and good luck. Course my dog is overweight and that little margin will be shaved. :h
I can't help but think about that tire rating when I go around the curves in the Smokies.