What is the proper tire pressure for these trucks (F250)?

Sidewall says max is 80 PSI.
Door jam says 71 PSI.

This is coming from a guy who has traditionally driven passenger cars and trucks. I've never even gotten CLOSE to advertised max PSI ratings. 71 seems awful close to max PSI.

mike

 

Go with what the door jamb says

 

I always run all 4 at 72 year 'round. Some people run them alot lower for a softer ride. Can drpend too on the weight you're carrying, or what you're driving in (like sand).

 

The proper pressure to carry the rated load for the truck is what the load info sticker says.... IF and only if the current tires conform to the original specs. If the tires have ever been changed to a different rating, you can't use the sticker anymore.

The correct way to lower pressures is to find the load index table for your tire and set the pressure where the chart says to based on the actual weight of the truck empty. You have to increase pressure again to carry any load though, and you have to look up the table for non-conforming replacement tires.

The quick way (which will usually result in a higher pressure than the correct way for a margin of error) is to take the weight carried by the tire divided by it's max capacity and use that as the ratio of pressure to max pressure.

2556# actual / 3195# rated = Xpsi carrying / 80psi max capacity. X = 64psi

It is perfectly fine to run the tire at basically the maximum inflation pressure, the only side affects would be faster centerline wear. My truck is specified on the load sticker to 75psi out of 80 max on all four corners.


Oddly enough FGAWR is: 3000# rated /3195# tire capactiy = X / 80.... X= 75psi. RGAWR 3050# /3195# = Y / 80... Y=76psi. So look at that, the math works, and gets to +1psi of the actual load rating.

 

If I'm driving around empty I usually run around 68-70psi in the tires. It helps smooth the ride out some and still keeps the tires wearing pretty even across. Anything over 70 is too much IMO, unless you're loaded down. Towing/hauling at or close to max I'll max the tires out.

Another thing you can do is make a chalk line across the tire then drive back and forth a few times and see how the chalk wears. Set the psi to get the chalk wearing off even across the tire and that will get you pretty close for the proper psi.