What do you guys run or recommend running for pressure, 325/65/18's on stock wheels?

 

You should run with the pressure printed on the tire. All tires are not made the same, or have the same characteristics. The manufacturer decides the best pressure to insure the tread works as advertised. Heavy duty tires carrying large loads generally require higher pressures. Auto tires on small cars require less pressure. The tire pressure label on the vehicle is for the tires that were installed at the plant. In my case they were General tires. But change the tires and you make that label obsolete unless the tires are the same or require the same pressure.

 

Not true. Tire pressure on the label inside the door is the proper pressure for your tires at max gvr. The pressure on the sidewall is max pressure for the tire. The tire mfg will usually have a chart showing recommended pressure for axle weight, but the door tag is usually correct. That all goes out the door if you change tire type, drastically change tire size, etc.

 

And the specified pressure is to carry the weight on the door. All manufacturers have tables that show what a tire can carry at a given pressure. That is why so many folks reduce pressure when running empty. Tire carrying capacity also is reduced as speed increases and increases as speed is reduced. I think it is Michelin that has some nice tables showing these relationships or at least did in the past.

Steve

 

I stand corrected. Perhaps I should study this further. Or not. Thanks, Thomabb.

 

Hope I didn't offend. I burned through a set of drives in 15k miles because they were inflated to 80psi. She is my daily driver and is empty most of the time. Replaced them, did the chalk study and found they ran best at 55 - 60psi. Still ramp them up to the pressure on the door sticker when hauling. Now I get 40k on my drives.


Tire pressure on a vehicle that changes gross vehicle weight drastically is a moving target.

 

I've been doing the chalk test for years. It's a simple yet effective means of determining the proper air pressure for tires. The factory recommended pressure for the front is pretty close. I usually only drop about 5 psi. But the rear is way over psi for running empty. You can lower the rear psi by 15 to 20 psi. The ride is smoother, tires last longer, and no loss of fuel mileage.

 

For me, when empty I run about 65 psi all around. When loaded and/or pulling the TT, I have found that 55 in the front and 80 in the back give a good ride and feel.....I am running Load E AT tires.

 

Do know if anyone watches Project Farm on YouTube, but if not be prepared to kill a few hours. I love his videos:

 

 

I run 70 in front 80 in rear on my 2001 PSD. My truck tips scales at over 8200 because it is loaded with my work items....

But back to the door sticker

20 years ago or so many , many Firestone ATX tires mounted on 1990's Ford Explorers were failing. Causing the roll overs and other accidents.
I believe it was because the door sticker said inflate to 26 psi. I believe Ford set this pressure because it made for a smoother ride.
I always inflated mine to the max 35 psi. Once I did notice that I did get the tire separation in about 1999.
That was after driving over 100 K and always putting on fresh Firestones all the way around.

I was a tire man in the late 1970's. I mostly inflate all my vehicles to max. rated pressure printed on the sidewall.
I realize I am getting a harsher ride, and maybe reducing the mileage life of the tire. But, I feel the tire wears more evenly on the footprint, rather than wearing on the tread closer to the sides of the foot print.

Also most of my driving is commute length, about 10 -25 miles each way. Definitely on long road trips, I may lower the pressure due to the fact that the long drive and heat are going to raise the pressure.

 

DOT study show tire that are less then 75 % of the tire max inflated value is an unsafe tire.

Running tire on hot payment ,, the air in the tire expand ..

Tire pressure on the door is for factory tires. brand and size.. change from that brand and size .. run tire pressure 5-7 psi less then the tire rated max PSI.. to allow room for the air to expand. Never run tires inflated to max PSI rating on the tire.

 

325/65/18 BFGs on my F350. running them at 60 psi.