I just changed out my Goodyears to Bridgestones due to a steer wheel blow out. When roadside assistance arrived all they had was a Bridgestone, not my first choice but when stuck in the middle of nowhere I'll take it! I always rode on 80 PSI on the front and 85 PSI on the back due to weights taken on the 2 axles. Rode nice. However, when I tried to do the same on the Bridgestones, road play and loose tires seemed to get me. Felt like there was so much play side to side in the tires, very loose, I upped them to 90 in the front and 95 in the back. Much better handling and no real difference in the ride. 110 is the max sidewall limit, 85 is the house placard suggestion, 90 is on the chassis sticker. So many different variations, as long as I'm in between, not under according to the charts and over according to the tire manufacturer...ride and handling dictate it all.
Weight of vehicle ready to roll and the tire manufacturer's chart recomendation is the only "accurate" way to decide. Now if you get a weight for each tire position and apply that to the chart you will have the best setting, along with may find a loading problem with overloading one position!
Next best is axle weights, make sure you have your exact model and size of tire along with load rating, a letter. While you may put the same tire size on as a replacement the manufacturer may rate the tire lower or higher than originial tire so the placard may not be any help.
The only exception is if the recommended pressure is above the wheel rating, which means you have the wrong tires or wheels on.
Ray, Cheryl & of course Miss Molly the four-legged child
I’ve found the information contained in the references listed below to be very informative. They will answer many of the questions being discussed in this thread. It requires a little knowledge of the DOT regulations but most readers can put the two and two together.