# Tire Pressure



## hillbilly47 (Jan 3, 2008)

I am running LT265/70R17 Bridgestone tires on a Chevy 2500HD truck. Chevrolet says to run 62lbs. in front and 70 lbs. rear. Bridgestone says don't go less than Chevy specs. I know I need to drop air pressure on the beach. What pressure are yall running for those who have the same size tire as I do or similar


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## clpoudnine23 (Dec 21, 2005)

Try running 25 lbs. That is what I run on my 3/4 ton diesel and have no problems. For the street the tire pressure is 70 lbs. I would also suggest a tire deflator (tire buddy II) to get you from 70lbs to 25lbs, much easier on the back.


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## Greg's Baitshack (Nov 5, 2007)

try this:

On a dry day, pour some water in front of your to front tires, drive through the water
and see what kind of footprint you are getting with the PSI your running now. If its not a full footprint lower the air pressure and repeat until you get a full footprint. Do the same for the rear. I like to get a full print on mine, they seem to wear better.


Greg


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## basstardo (Jun 5, 2006)

Greg is on point. Running the stock tires on my 02 F250 at the recommended pressure produced uneven wear. The torque of the diesel actually cause a little premature wear in the rear as well, so I had to rotate more often. I've never tried Greg's method, but I certainly agre with the footprint/even wear theory. I played around with mine until I got a good balance of handling and tire wear. I rotate my tires every 3000 miles too though, which I think helped out some.


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## scavengerj (Sep 10, 2007)

Hmmm, I like the water method for inflation pressure. I have never tried that. I have always chalked my tires. Basically the same principal. I draw a chalk line acroos each tire and drive a short distance on a flat paved road. Then I look at how the chalk has worn to determine if I have the right pressure. If I am going to be carrying a load then I'll up the pressure a bit. Have always wondered about the right pressure for the beach though as is hb. Most seem to say 17-18 psi. Just seemed to be really low for a tire that is supposed to be running at 65-70psi on the road. Have always worried about popping a bead running that low.


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## ReelinRod (May 29, 2003)

I'll repost what I wrote in *a thread a couple years ago*; well worth reading for the good discussion and differences of opinion  

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Airing down isn't just about not getting stuck.

Airing down reduces the strain on your entire drivetrain especially the transmission and transfer case. Driving on loose sand with hard tires takes its toll on those components.

There is a way to determine what the optimal tire pressure is for your vehicle:

Perform the following test on a flat, level and smooth surface, fully loaded as you would be for a sand run (gas tank full, passengers, cooler rack etc. included). Measure the vertical height to the bottom of the wheel (rim) from the ground. This is your 100%, street pressure, wheel height. Now reduce this height by 25%. In other words, let out air until your wheel is 75% of the street height. Measure and record this pressure and depending on your vehicle and loading scheme, front and rear tires pressure will probably differ.

This is your optimum sand pressure. This reduction typically results in more than a 250% increase in footprint area. That is like having ten tires where you only had four. This pressure is only valid for exactly what you tested. Change vehicle, tires, wheels or load and you have to retest.

Too low a tire pressure isn't good either . . . The center of the footprint begins to well up reducing the effective footprint and creating a small “traveling hill” in the center of the footprint. This hill offers increased resistance to vehicle movement.

Here's a visual on the 25% decrease and increased footprint:


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