- May 16, 2022
- Reaction score
- Buffalo, MN
- Ram Year
- 6.4 Hemi
I can hazard a guess how they come up with it. In the chart you linked to, if you find your tire size and look in the column for 65 psi, it says the load carrying capacity of the tire at that pressure is 3195. 3195 X two tires = 6390. Guess what the Gross Rear Axle Weight Rating on a gas engine Ram 2500 is. Hint...its 6390. So I don't think its a coincidence that they tell you to use a pressure that ensures your tires are able to carry the same load as the axle. But to me that means that it really is not necessary to use 65 psi when the truck is unloaded. Just my opinion.Like I said above my pillar is front 60 rear 65 for the stock 275 70 18 Firestone Transforce ATs. The manufactures inflation chart from Firestone for the OEM tires shows https://www.google.com/url?sa=t&sou...cs-sites/firestone/TBR/load-inflation-tabmuch lower tire pressure of just over 45 psi at 2500 pounds per tire than the door post shows me.
I would truly love to hear how Ram comes up the the pillar inflation pressures and what their rational is for recommending tires be so over inflated. Got to be a reason but I sure can't figure out what it is.
What I'm now curios about is why mine has a sticker that says to use 70 instead of 65. I suspect that its because I have the 20 inch wheels with size 285/60-20 but unfortunately I'm not finding that size in the chart.
Edit: I found another source for my size. Its not an official firestone reference but it looks useful.
Find corresponding tire load capacity at specified tire inflation pressures for LT285/60R20 tires to maintain proper tire inflation for a safe drive.