Tire pressure does depend on GVW also the type of tire, manufacturer, etc.
We have 19.5 inch tires, our sticker inside says 80 psi, the tire says 95 psi max. According to the manufacturer's inflation chart, 80 psi is fine for the weights we got when we weighed the coach, however, I like to run the tires at about 90 psi. The coach actually rides smoother at that pressure then at 80. Sounds strange, but all i know is at 80 the bumps hit a lot harsher than at 90. The tire wear so far at 90 seems OK as well and not wear the center of the tire because of over inflation and tire temperatures are good also.
2010 Georgetown 330