Best Truck/Suburban Tire Pressure?

[Duncan Sterling]

Howdy,

Just wondering what other folks are running for tire pressures.

My R2500 Suburban door sticker calls for 45 PSI front and 75 psi rear, which rides pretty rough. I'm thinking I can probably get away with 45 PSI on the rear too so long the vehicle is only lightly loaded, then pump it back up to 75 PSI for heavy loading, lots of passengers.

What's worked best for you?

Does anyone think that running less than 75 PSI in the rear tires under any circumstances is a bad idea, and if so why?

TIA for any and all comments,

--Duncan

[aloharovers]

75psi sounds pretty extreme for an unloaded vehicle.
What size tire are you running? And what load rating are they?

Best thing to do is to have the truck loaded as normal daily driving. Fuel tank of fuel.
Find an empty parking lot.
draw a line with chalk on all four tires. Accross the tread.
Drive straight ahead about 20-30 feet and then check the chalk marks.
If its more worn on the edges then tire is under inflated.
If more worn in the center then over inflated.

Its old school but its the best way to get it just right for the vehicle.

Pete

[Duncan Sterling]

Originally posted by aloharovers:
75psi sounds pretty extreme for an unloaded vehicle.
What size tire are you running? And what load rating are they?

They are the stock 235/85/16 E rated tires for suburbans. The tires themselves take a max pressure of 80 PSI.

I was simply guessing that since the door sticker says 45 PSI is OK for the front tires when fully loaded, that it would probably be safe for light or half load in the rear instead of 75 PSI as the door sticker calls for.

[dieselbegreat]

I have a 3/4 ton and the rear shocks get worn out pretty fast driving around empty with high tire pressures. I have the Michelin Radial X your size and for normal driving keep all the tires around 50psi and within 4psi between front and rear. You will notice a difference in handling (over/understeer) with pressure and can tune it somewhat. I felt the steering was just slightly too squishy at 45 psi and the extra 5psi made a big difference. Any more than that and it gets too harsh. Then I'd fill the rears up to 55psi and adjust downward from there till you like it, but not more than +/- 5psi difference with truck unloaded.