I used Google to find a Firestone commercial tire loading and pressure pamphlet.
This is the PDF page that I found.According to it the minimum tire pressure required to set both front and rear axles to 5360 pounds for a LT275/70R18 (my Ram 2500) is 50 psi.
I went through weigh tickets from my existing TT and my old 1500 and found that the most the TRUCK ONLY rear weight above daily use on any trip was 620. The most the TT tongue weight ever scaled with fresh tank full and a load of baggage and food was 700 pounds. So I add 700 heavy tongue to bed full of firewood and come up with 1320. I round to 2000 with heavy duty new truck because I can.
New truck scales at 3000 rear and 3960 front, full of fuel and all sorts of truck stuff like tow straps, tie downs, jumper cables, etc., and my emergency bug in backpack full of too much stuff to recount--but no she or me.
I arbitrarily took new truck rear and added a rounded up 1000 pounds each for both excessive cargo plus excessive tongue weight and came to 5000 pounds rear axle. I looked at the table and found that 50 psi in the rear tires would readily accommodate 5360. That's 10 psi below factory recommended 60 psi for the front axle--whether loaded heavy or light--though not quite enough to carry the factory front axle rating of 5500 pounds.
Front axle is only 4000 pounds, and even heavily loaded (for my purposes) with 2000 pounds of tongue and other cargo, with even half of that distributed to the front axle rather than the rear; front axle will never carry more that 5000 pounds.
Again consulting the Firestone pamphlet, I determine that 50 psi in all four tires will more than cover anything I throw at my truck tires whether running light to work and back, hauling a big load of home improvement from a box store, or pulling my current camper loaded even to its GVWR of 6800 pounds. It's overkill, even.
TPMS system be danged. I will deflate my tires to 50 psi all around before I leave for work in the morning. At 50 psi it will be safe to do all I ever ask of the truck or the tires, and after I scale it a time or two with camping cargo loaded and hooked up I'll adjust it from there if I decide it might be lowered. If I ever find the perfect 5er I'll up it to 80 in the rear and 60 in the front for towing.
FCA will get a nasty-gram this week on the hazards of over inflated tires and the willful negligence required to put millions of such vehicles on the road in an effort to avoid a few extra paragraphs in the owners manual designed to educate owners on the proper management of tire pressure.
If anyone finds a flaw in my above inflation logic, please let me know so that I can better adjust both my understanding and my tire pressures.
And before I make an *** of myself in my nasty-gram to Ram.
Cheers from East Tennessee.
