I got 110 psi from the tire manufacturer as max PSI for max loading (about 3500 lbs per tire). According to that logic I could put about 8 tons on my flat bed.
Just checking to see if anyones listening. I believe my shop manual (it just arrived) says somewhere around 40 psi for the fronts and 60 for the rears. Lets see... at 9600 max gvw (lets assume 5000 lb truck) I've got 4600 lb of load I can haul. Lets stay on the safe side and call it 2 tons max.
Anyway, I'll not be hauling 2 ton loads of whatever any day soon, if ever.