Stage Right, this is a good thread topic and thanks for raising. Factories and dealers set the pressures high (usually at 40 psi or higher because the car will often sit in one spot on a cargo ship or parking lot for a long while and a higher inflation will reduce the potential for flat-spotting the contact patch while parked. It's frustrating that they let customers test drive these cars with over-inflated tires because it really does change the handling feel in a negative way, potentially turning buyers off. I always take my Longacre Race gauge with me to dealers and deflate the tires to door label spec before I drive to get accurate handling feel. I typically follow the Porsche rule of 69 degrees F as the setting temp and calculate one PSI per 10 degrees F up or down from there.
As for following the door label, it's good to adhere to this as a starting point, even when staggered - the manufacturers factor in all the testing and development data on front/rear weight bias of the vehicle, which wheels are driven (an added vector) and what the legal/mechanical strategy is regarding how much they want to dial out oversteer (rear-end slide). However, these are only starting figures, and if you read deeper into the owner's manual, you will often find a clause that states "inflate tires to higher PSI when vehicle is loaded. Load means cargo weight and it really does require (for tire bead and sidewall safety) a higher PSI to offset the higher load. **Also note that high speed is a factor here too. If you plan to do a run over 100mph or more, the rotational forces on the tire bead and sidewall are immense, creating enormous heat. A higher PSI will help reduce the strain on the tire - if you read any BMW Owner's Manual, there's a whole section on how to inflate tires for speeds over 100 mph. BMW, to their credit, recognize many owners will often do this, regardless of the local laws in any country they sell cars in.
So, if you're riding by yourself in the Durango with minimal load, simply follow the door pressures and you'll be good. If you pack the family and dog in and add 600-800 lbs to the car's gross weight, go ahead and add a few PSI to each tire. Yes, the tires will heat up from use and heat causes the pressures to rise, usually by 2-4 PSI depending on conditions.
Lastly, and the Challenger and Charger guys know this, if you track your car (meaning you're lapping at the limit for 20 minute sessions in a run group) then you should lower the pressures way below door label specs because in about 4 hard laps on a 1-3 mile circuit, your tires' PSI will jump up 7-8 PSI, easy. And if you started at door label, you'll soon be well into the 40s and slippery (sliding all over the place), losing time, getting frustrated, and damaging your tread life.
