What air pressure should I run?

I am going to replace the tires on my 2003 Tacoma with the same thing it has on it (33x12.5r20 Nitto mud grappler). My question is what tire pressure do you think would be best to run in these? I was thinking 38-40 but they recommend 65.

 

Use this calculator to help you determine your new pressure. Just plug in your stock tire size and recommend pressure from the door jam and enter your new tire/wheel size:

 

Interesting site. For typical around town I'm at 33 psi.

 

I run 29 in my 33s. 38psi is alot, 65 is insane.

 

I run 55 on my 235 when towing. Any less and they get hot.

 

30 cold 35 warm 40-50 with load for LT tires.

It's a light truck and will never see the weight that the tires were intended for.

 

Reading all these comments, I wouldn't listen to any of them. Every vehicle is different. The BEST and only way to know what your tire pressure should be set to, is to do the chalk test. All other opinions are 100% wrong and invalid.

 

The chalk test is a static method that doesn't reflect how tires behave under real driving conditions like cornering, braking, or heat buildup. It can give misleading results because it only shows the contact patch when stationary or rolling straight at low speed. For modern tires and performance tuning, it's better to use temperature readings, tread wear patterns, or real-world handling feedback.

 

All that is cool in theory, but it falls flat when you ask people with real world results who drive over 20k miles a year with the same tires they offroad with. On my old 33" load E tires, the chalk test determined I should run 35psi up front and 25psi in the rear (when empty). ~3 years of hot summers (~110 degrees) and neglected alignments and my tires never skipped a beat.

The chalk test > all

 

Pyrometer> chalk test

 

Chalk test > your opinions

 

I get 15 mpg and never get flats

 

A person at a shop? Or the number on the side of the tire?

Tire manufacturers put a maximum recommended pressure on their product so they can't get sued if you overfill it and it blows up

If an employee told you to put 65 psi in a 1st gen Tacoma with anything less than a camper or load of dirt in the back then they shouldn't be selling tires.

 

I saw the 65lbs on their website and on the tire. I knew that was way too high for this truck but wasn’t sure where in the 30’s I should be. When I put 38 in them the truck rode like it had a flat spot on the tires.

 

Who's "they?"

 

That's the max limit I was talking about. It literally serves no purpose except to protect them in court


The folks who designed the vehicle put a good starting point on the sticker on the door jamb.

Off the top of my head you should be somewhere in the low 30s

 

Like Bishop mentioned above, you're never going to come close to hauling the weight those tires are rated for with your 1st gen. In terms of load carrying, LT tires are for big trucks carrying campers and towing trailers.

On a small pickup like the Tacoma LTs are generally used for extra protection while offroading with low air pressure. So forget about these crazy high load-carrying pressures. You'll be experimenting with a balance of comfort - low 30s to high 20s..

If you're out on some washboard roads don't be afraid to go down into the low 20s.

Actual crawling and technical "offroading"? Guys go down into the teens and really lay that tire out like a tank track..

That is the true practical benefit of 10 ply tires