'E' Rated tire pressure? - Toyo MT 285/75's

[alta825]

Curious what tire pressure I should be running w/ my E Rated Toyo MT's 285/75/16's

The SMB sticker in the door jamb has 55psi written on it, but it was also originally specced w/ the D Rated BFG AT's 285/75/16

On the last 2 trips to Fruita the ride seemed a tad rough - curious if I should adjust the 55psi up or down due to the E rating

Thanks

-d

[Ford_6L_E350]

First, you need to know how much weight is on your tires. Then you can calculate the pressure for each tire from the ratings on the tires.

For example: If your van weighs 10000# with 5500# on the rear and 4500# on the front, evenly divided side to side and your tires are rated at 3200# @80 psi.

Divide the tire rated load by the rated pressure to get a pressure capacity.

Divide that number into the load to get a pressure for that tire.

From the example:

3200# divided by 80psi = 40#/psi

for a 2750# load on a rear tire, 2750 divided by 40 = 68.75psi

for a 2250# load on a front tire, 2250 divided by 40 = 56.25 psi

A lighter van needs less pressure, a heavier van more pressure.

Higher pressure is safer - less flexing, less heat buildup.
Lower pressure may ride softer, but may 'wallow' more in turns.

Not know your weights and tire ratings, I would guess your pressure are close, but maybe a little low.

My van weighs 9800# has 275/70-18E tires and runs 65 psi all around.

Mike