Hankook 19.5 Tires on Your Pickup Tires?

My F250 had 245/70R19.5 tires that were LRH 16PR. Although I did not need all the capacity (I was usually close to 8k lbs on the rear axle), I was able to run these tires at less pressure than than typical LRG 14PR and still have the same weight rating. The reduced pressure helped the ride a little and made it easier on the compressor when I went from the 70 PSI unloaded configuration to 100 PSI which gave me 4500 lbs per rear tire.

Your GM may have some slight fitment problems with the 245's in the front. You may need to cut back your fender liner, crank up your torsion bars or run a leveling kit to keep them from rubbing.