Originally Posted by MuddauberE
...It does matter if you change tire ratings and even size as mentioned by OldCoot and Pap. recommended tire pressure is based on factory tires for your vehicle. So if you did upgrde, then your door jam is probably wrong. But even with factory tires, look at the door jam, and then look at the MAX PSI. they are not the same. Usually about 20 lbs off. Your max air pressure is just a safety rating. go above that and your being dangerous. Always check with the dealer if there is a question and they will tell you the same thing. Always get more than one "opinion".
If you change tires to a different LR, the factory door sticker means nothing. Tow Vehicle mfgrs are not interested in anything but the "Ride" of the vehicle, not tire wear or performance when loaded. On the trailer, I inflate to max sidewall pressure in the morning and go with it. If it happens to be colder and the pressure is less than I set it for the morning before, I air them up. If it is warmer and the pressure is above the max, I lower the pressure to max. I never adjust pressure during the day while towing. The tires are built to withstand the temperature/pressure change while running. The TST TPMS has warnings you can set to alert you to a % increase in pressure and an alert on the temperature that you can set.