hAVE 2500HD duramax single wheel and two 28 ft enclosed car hauler, what tie pressures should I run?

The tires are 10 ply 265/75/16s!

probably would help us to know what kind of tongue weight or kingpin weight you've got.

I think I ran 55 or 60 in the front and 80 in the rear when towing heavy.

Here's a formula that I found and have been using.

Tire Air Pressure
axle weight / number of tires X max air pressure / weight rating of tires used = tire pressure needed
ex: 5000 lbs axle weight / 2 tires X 80 psi max air / 3042 rating of tire = 65.75 PSI needed.........
ex: 5000 lbs axle weight / 2 tires X 80 psi max air / 3415 rating of tire = 58.57 PSI needed.........

Here's the way I worked it out for my truck and trailers:


Obtain a tire inflation vs. load chart (any tire manufacturer – they are all essentially the same)
Inflate all truck and trailer tires to the maximum cold pressure indicated on the sidewalls
Hitch up and load the trailer
Load up the truck to normal for the kind of trips you will take (fuel, family, dogs, toys, tools, etc.)
Go to the nearest scale and obtain axle weights

Truck front axle
Truck rear axle
Trailer axles (combined weight is easier to get that separate axle weights, but remember then that it’s 2 [or 3] axles and 4 [or 6] tires)

Divide each axle weight by the number of wheels/tires on the axle (e.g. 4 for a dually) to get the load on each tire

Adjust the cold inflation of each tire to the amount specified in the chart for that load plus 10 psi
Do not go OVER the maximum pressure on the sidewall
Do not go BELOW the minimum pressure indicated on the chart plus 10 psi
Be sure you’re reading the correct line on the chart – single or dual application

Compare the front axle weight to the truck FAWR and the truck rear axle weight to the truck RAWR to be sure you’re not over the axle capacities
Add the front axle weight plus the rear axle weight and compare to the truck GVWR to be sure you’re not over the truck capacity
Compare the trailer axle weights to the trailer GAWR to be sure you're not over the trailer's capacities
Have fun towing:)
Ralph

Too many formulas for ol' JJ. ):h I've always operated under the premise that the only reason to run a tire below max pressure is for comfort. Tires operate at their highest efficiency and safety when they are properly inflated for the job at hand. When towing you need for the tires to carry the load without compromising the structural integrity of the tire and to maximize their handling characteristics. :rolleyes:

When I tow heavy my tires, truck and trailer, are at max pressure. Best to check them before each trip because trailer tires lose pressure as they sit, especially in cold weather. When I'm done towing I drop them back down for comfort. JJ's .02 cents worth. JJ :)

;) Ditto to JJ......

When I'm towing heavy I always air up to 80lbs, even if it's not necessary for the load. I want the sidewalls as stiff as possible to reduce any tendancy to sway to the minimum (not really an issue for 5th wheel or goose neck trailers).

TC

Paper calculation method
Empty:
55 lbs in front
50 lbs in rear

Towing: 1600 pund pin weight plus extra "stuff"
55 lbs in front
75 lbs in rear

The best thing to do as previously stated is to get your truck weighed. Then there is no guess work.