We have been running 19.5 Michelin's on Rickson rims for about 4 years.
I bought them for the increased weight limits on the rear axle and also just as important to us, the straight, stiff sidewalls, less tearing of the sidewalls in rocky conditions.
I am somewhat concerned about the increased weight on the weak Dodge front end suspension, when we hit pot holes there is a lot of crashing, pounding and banging. So far only had to replace the front sway bar end links a few times...
Fronts are around 80 pounds PSI, about as low as I would take them down.