I took my truck to a dealer in Virginia Beach after finding my warranty information. Apparently, that information is not shared my "independent" dealers. After three hours of waiting I am told that my wireless control module, WCM is bad. One of the tire pressure sensors failed a test but passed it when run a second time. The dealership didn't have enough sensors to replace all of them so they didn't but they did replace the WCM. Replacing the WCM requires your keys to be reprogrammed. No biggie but since I was out of town at the time of repair, I only had one set. Anyways, the repair turned the lights off, until I got one yesterday. I had today off and went down to the dealership by my house, I live in Stafford, Va, with my spare key and invoice from the dealer in Virginia Beach. I was told that I could wait until all the appointments were done, or schedule an appointment for a later day and they would charge me $50 to reprogram my spare key because. I showed the service manager my paperwork from the VB dealer and he said, so, they aren't going to pay me to reprogram your key and that takes half an hour. So I guess the moral of the story is, one, always call and make an appointment, arrange for a ride or bring a book and two, always carry your spare key when going to the dealership.

 

Do you have 2 working keys? if so you can program a 3rd.

The truck should have 2 key fob keys and 2 valet type keys, or do you only have 2 total?

 

Getting back to the 50psi thing - tires are made to handle X amount of weight at Y pressure. Most load range E tires are designed to handle about 3200 pounds at 80 psi, you start dropping pressure and you drop the load capacity. The rubber flexes more, generates more heat, and is prone to failure.

While you could probably be fine, running around empty all the time at 45 or 50 psi, if you load it up and don't have access to air you're going to be underinflated.

The other issue is contact patch. The weight of the vehicle, pressure in the tire, and size of tire itself all contribute to making a proper contact patch. Too little air and you're going to wear the shoulders faster among other problems, too much air and you'll wear the center of the tire. If you're running larger tires than stock then lower pressure might be appropriate. You would have to do the math though (which I don't know). You can cheat and do the drive-through-a-puddle-and-look-at-the-tread-pattern-left-on-dry-ground method, and see if you're getting a good contact patch or if it doesn't look quite right, then adjust up or down from there.

The factory goes through a lot of work to decide what pressures should work best for a given suspension/steering/weight. Their factors include tire life, fuel economy, NVH, and handling (and probably other things).

Dropping pressure would most likely decrease NVH and improve ride quality, but it would also decrease fuel economy, tire life, and handling.

In my old w250 I used to run 80psi all the time for better mileage, but the ride was harsh. It did, however, handle pretty well. Then I lifted it and put 35" tires on it and I think the max pressure was 65psi on those, which I kept it at.