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Question about PSi for Toyo MT - 33x12.50r20

toddboy23

By toddboy23
in Tires, Wheels & TPMS

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toddboy23 Enthusiast

toddboy23

Posted
Posted

Guys,

 

I just had my tires mounted Friday and I'm trying to figure out if I need more air in them.

The numbers change throughout the day from temperature changes but on a cold start this morning at 59 degrees, these were my numbers. Tires are 33x12.50r20 on stock GMC 20x9. 2014 Sierra.

Front: 31 35
Rear: 32 32

Thoughts?

dirtfan21 Senior Enthusiast

dirtfan21

Posted
Posted

On my 2008 half ton Silverado I had E rated 285/65/18 Trail Grapplers and I ran 35 PSI in them. They wore great for approx 25k before I traded the truck in.

CAtaylor Enthusiast

CAtaylor

Posted
Posted

Not sure what tires your truck originally came with but for example.

The SRA 265/65 18 would carry 2469 lbs at 51 psi. Roughly 48.5 lbs per PSI.

The Toyo 33/12.50 20 will only carry 2600 lbs at 65 psi, even though they are a 10ply E rated tire. Roughly 40 lbs per PSI

 

This is quick and wont be exact:

Look at the door jam and see what the recommended pressure was for the factory tires. If they were the 265's you can use the above numbers. Not sure what yours says but Example below

Front recommended 42psi. 42 x 48.5 = 2037 lbs. 2037lbs \ 40 lbs per psi for the Toyo will equal 50 psi.

 

I went through this when I installed that exact tire on my 2012 GMC2500. The above will get you very close to where you need to be. If you want to get it exact put you some loose chalk down on the driveway and drive through it. You should have even chalk coverage across the tire tread.

toddboy23 Enthusiast

toddboy23

Posted
  • Author
Posted

Not sure what tires your truck originally came with but for example.

The SRA 265/65 18 would carry 2469 lbs at 51 psi. Roughly 48.5 lbs per PSI.

The Toyo 33/12.50 20 will only carry 2600 lbs at 65 psi, even though they are a 10ply E rated tire. Roughly 40 lbs per PSI

 

This is quick and wont be exact:

Look at the door jam and see what the recommended pressure was for the factory tires. If they were the 265's you can use the above numbers. Not sure what yours says but Example below

Front recommended 42psi. 42 x 48.5 = 2037 lbs. 2037lbs \ 40 lbs per psi for the Toyo will equal 50 psi.

 

I went through this when I installed that exact tire on my 2012 GMC2500. The above will get you very close to where you need to be. If you want to get it exact put you some loose chalk down on the driveway and drive through it. You should have even chalk coverage across the tire tread.

So in short - about 38 psi for the Toyos on my truck.

 

Kidding aside, that was a great explanation, thank you. Door jam recommends 32 psi F and R. The stock 275/55/20 SR-A is 2403 lbs at 51.

 

So that's 2403/51 = approx. 47.

32x47 = 1504

1504/40 = approximately 38 Psi

CAtaylor Enthusiast

CAtaylor

Posted
Posted

So in short - about 38 psi for the Toyos on my truck.

 

Kidding aside, that was a great explanation, thank you. Door jam recommends 32 psi F and R. The stock 275/55/20 SR-A is 2403 lbs at 51.

 

So that's 2403/51 = approx. 47.

32x47 = 1504

1504/40 = approximately 38 Psi

You got it!

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