My swag, the big three could easily come up with 7500-8500 grawr setups, have 500 min more lbs of payload than an equal dw setup. My 286 65 18 tires on my 1500 are close to 4000 per tire. A 305 or 315 should put one over 8000.
Marty
Last winter I checked in on one of the Dodge/Ram diesel forums where one forum member does a talk with a Ram engineer topic every so often.
The very question came up why doesn't Ram uprate their 3500 srw 11.5" AAM rawr to 7.8k-8k + lbs.
Engineer covered a few reasons but the main one being new OEM uprated wheels (load and diameter) would have to be mfg'ed and the tire industry would have to come up with tire lines to meet 4k-4.5k tire diameter and load ratings/psi rating and possible a F load range for the new OEM wheels.
GM may be the first to upgrade their 3500 srw to the 8k +/- range. They sure made a good move on the 10500 rawr on their drw trucks.