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post #1 of 5 Old 03-05-2013, 11:59 AM Thread Starter
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PSI question/help

What is the proper psi for Toyo Open Country MTs 38x15.5 on a 20 inch wheel?


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post #2 of 5 Old 03-06-2013, 03:46 AM
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Originally Posted by mad103 View Post
What is the proper psi for Toyo Open Country MTs 38x15.5 on a 20 inch wheel?
Depends on your application. Offloading? DD? Doubt your towing with 38x15.5?

2013 Lariat Eco-Boost F150 Super Crew 4x4 20K Miles. Max-Tow 3.73's, luxury package. Amp Steps, Raceline Raptor Wheels, Bak-Flip, and much more.


(Sold) 2011 Lariat 6.7 F350 CCLB SRW 4X4 60K MILES
Nitto Terra Grappler 295/70/R18 on OEM's
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post #3 of 5 Old 03-06-2013, 08:12 AM
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I am running 55/50 F/R on 37-12.5-20 nitto trail grapplers an 50/45 F/R on 37-12.5-17 trail grapplers. These are my street pressures.

Off road it gets down to 35/30 regular and less if it gets sticky

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post #4 of 5 Old 03-06-2013, 11:35 AM
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Originally Posted by BIG Laing View Post
Depends on your application. Offloading? DD? Doubt your towing with 38x15.5?
Your wheel width will come into play here as well. You can run more psi with a wider wheel and not have the centers bow up as much than a narrow wheel at the same psi.

For daily driving, try running a chalk line across the tire and drive around the block. If all of the chalk is gone, note the psi, add more air, repeating the process until you see chalk on the outside shoulders of the tires. At this point, deflate to the last psi.

I ran my now discontinued Toyo 356/65-16s at the sidewall printed max of 50 psi and ended up running the centers out of them. Now that I am on BFG 315/75-16 ATs, I have found that about 40~45 psi is about the sweet spot for even wear. Like I told the monkeys at Discount Tire in Las Vegas after they tried (against my instructions not to) increasing my psi to the sidewall 50, "I didn't spend $1000 on those tires to ride on the center 6 inches of tread!!"

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post #5 of 5 Old 03-06-2013, 10:48 PM
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Quote:
Originally Posted by Karls03 View Post
For daily driving, try running a chalk line across the tire and drive around the block. If all of the chalk is gone, note the psi, add more air, repeating the process until you see chalk on the outside shoulders of the tires. At this point, deflate to the last psi.
I have never done this ^^^ personally. Every-time I hear it, it makes me want to try.

I would now, but it's midnight and I have been

And yes Karl you got me Hook Line Sinker, on a tire post last week!

2013 Lariat Eco-Boost F150 Super Crew 4x4 20K Miles. Max-Tow 3.73's, luxury package. Amp Steps, Raceline Raptor Wheels, Bak-Flip, and much more.


(Sold) 2011 Lariat 6.7 F350 CCLB SRW 4X4 60K MILES
Nitto Terra Grappler 295/70/R18 on OEM's
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