Originally Posted by JoeH
I think that BFG has a load index of 121 and at 50 psi is rated for 3195 lb. That should be plenty, I wouldn't run more than 50 and you could probably get away with a bit less and your ride won't be as harsh.
This has been posted before but use this formula: (max psi/max load)*(real load) + 15% safety margin or whatever your comfortable with. Ideally you should know the weight over each axel.
For example my rig weighs 10,000 pounds and the tires are rated for 3860 at 65psi. So,
(65/3860) x (5,000/2) = 42 psi
42psi + 15% = 48 psi
My bfg a/t e-rated 285/75/16 are 3750 at 80psi
Ford factory sticker inside door column states:
Gawr is 4050lbs front; 6084lbs rear
(80/3750) x (4050/2) = 43.2
43.2 + 15% = 49.68 psi front
(80/3750) x (6084/2) = 64.9
64.9 + 15% = 74.7 psi rear
I suck at math. How's that look?
Also, the ford door column sticker gawr doesn't account for the added smb conversion weight correct?
Finally, would it make a big difference in tire performance to weigh the van loaded like you normally would travel with it and recalculate the correct tire pressure or are we splitting hairs?