Maximum tire psi for 2004 Ford E350

Is the maximum psi on the tire the cold psi?
When driving the psi raises to 90 psi on the RV tires. The maximum psi is 80? How do I determine the safe psi inflation for my tires?
Are my tires over inflated if they are 90 psi when they are hot?

Not if they are at 80 psi when cold.

You DO NOT inflate to the maximum PSI listed on the tire. You inflate to the PSI listed on the door jam or in your owners manual… this is done when the tires are cold.


Yes, Purebred is right. Do not inflate to the max pressure unless the vehicle tire placard says so. Further, the max pressure is COLD - meaning that the tire manufacturers factor in that there will be pressure buildup.

But getting a 10 psi buildup on an 80 psi cold tire seems a bit excessive.

Rule of thumb. You should not see more than a 10% pressure buildup. If you are then you need to slow down or getting more load capacity in your tires.

But if you see 15% or more you need to take immediate action - and that means slowing down AND replacing those tires with something with more load carrying capacity within a few days!

You get more load carrying capacity by using a higher pressure or a larger tire.


Are the current tires the proper size and load rating for the truck? And if not why not? I have seen 6ply tires mounted on light duty truck rims inflated to the 45psi that they require cause the rims to split at the beads.

Ply ratings are now just load ranges A,B,C,D, etc and pressures increase with the load range and tires should match the rating of the wheels they are mounted on.

I inflated the rear tires to max pressure on my 95 Nissan pickup when I hauled 1000 lb mid-rise lift.

Without doing so, the tires were almost flat from the weight.


1 Like