Tire Pressure

Bluegoose972

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Have 37x12.5x17 Toyo's on 17x8.5" wheels. Pressure was set at 40 psi, but can see that there is uneven wear. What pressure are you guys running with a similar setup. Thinking of dropping another 5 psi to 35 psi and watching the wear pattern.





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Amric

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Have 37x12.5x17 Toyo's on 17x8.5" wheels. Pressure was set at 40 psi, but can see that there is uneven wear. What pressure are you guys running with a similar setup. Thinking of dropping another 5 psi to 35 psi and watching the wear pattern.
28psi
 

kkuntz01

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Have 37x12.5x17 Toyo's on 17x8.5" wheels. Pressure was set at 40 psi, but can see that there is uneven wear. What pressure are you guys running with a similar setup. Thinking of dropping another 5 psi to 35 psi and watching the wear pattern.
Every vehicle is going to be a little different as to what PSI to run. The best way to determine what PSI will be best for your vehicle will be to do a chalk test on the tires like @FatBoy01 shared below. I won't lie, it can be tedious, but it will tell you where you need to be.

 

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About 28-30 psi should get you where you need to be.
 

kkuntz01

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About 28-30 psi should get you where you need to be.
But a chalk test will get him to exactly where he needs to be without spit balling...
 

OnlyOne

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But a chalk test will get him to exactly where he needs to be without spit balling...
Been there. Done it. 28-30 is pretty basic on 35’s and up. Just trying to help him speed things up. Tire pressures are going to rise and fall all day long. 1-2 psi difference with a chalk test isnt going to get anything exact.
 

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I run 25psi cold in my E-Rated 37" Coopers, and every time I tell someone they look at me like I'm nuts..... I've been doing this since 2012 on all my E-Rated tires(17" Wheels), and not once have I run into any issues. The chalk test shows that I can even go lower, but I'm content with slightly uneven wear at 25-27psi(depending on outside temperature.) There are formulas online that help you calculate tire pressure based on your GVRW & Tire Load Rating @ max PSI on the tires. When using that calculation it tells me to run 26psi on my Coopers when my vehicle is fully loaded(Which it rarely is, but I factor in bumper/winch weight etc.)
Early on I even used a Temperature gun to make sure my tires weren't overheating when on the highway for over an hour...
 

BillyHW

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The Rubicon stock LT metric tires of LT285/70R17 at the door jam recommended pressure of 37 PSI means each tire can carry a load of 2,189 lbs. (via linear interpolation from the table).

The Toyo LT high flotation tires of 37x12.50R17LT need a pressure of 25.6 PSI to bear the same load of 2,189 lbs. (via linear interpolation from the table).

Here are the tables I used:

http://octopup.org/img/car/tires/Ru...intcmp=na-pagena-article-data_reason-external

I'm not saying that's necessarily the best pressure to be running your tires at, but that's an informed starting point (i.e. lower bound) if you want to make sure you haven't screwed up all the load bearing characteristics of your vehicle.

Someone please check my math.
 

PaPasJP

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I run 25psi cold in my E-Rated 37" Coopers, and every time I tell someone they look at me like I'm nuts..... I've been doing this since 2012 on all my E-Rated tires(17" Wheels), and not once have I run into any issues. The chalk test shows that I can even go lower, but I'm content with slightly uneven wear at 25-27psi(depending on outside temperature.) There are formulas online that help you calculate tire pressure based on your GVRW & Tire Load Rating @ max PSI on the tires. When using that calculation it tells me to run 26psi on my Coopers when my vehicle is fully loaded(Which it rarely is, but I factor in bumper/winch weight etc.)
Early on I even used a Temperature gun to make sure my tires weren't overheating when on the highway for over an hour...
Exactly and couldn't have said it better.
 

BillyHW

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I run 25psi cold in my E-Rated 37" Coopers, and every time I tell someone they look at me like I'm nuts..... I've been doing this since 2012 on all my E-Rated tires(17" Wheels), and not once have I run into any issues. The chalk test shows that I can even go lower, but I'm content with slightly uneven wear at 25-27psi(depending on outside temperature.) There are formulas online that help you calculate tire pressure based on your GVRW & Tire Load Rating @ max PSI on the tires. When using that calculation it tells me to run 26psi on my Coopers when my vehicle is fully loaded(Which it rarely is, but I factor in bumper/winch weight etc.)
Early on I even used a Temperature gun to make sure my tires weren't overheating when on the highway for over an hour...
Hey, looks like your formula and my table lookups arrive at about the same number ~26 PSI. Cool. :movember:
 

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