What would be the proper tire inflation on

[Atreyus]

33" BFG A/T KO tires? It says 50 psi max, I have mine at 35 right now is that recommended? Anyone know the proper inflation? Or where I can look for the correction info?

 

[YotaZach85]

35 sounds about right. How wide are your tires and your wheels? I can't tell from your avatar but it looks like stock 15's so I'm guessing they're 15x7 so I kinda hope you're running a 33x10.5

 

[the great him]

idk, your kinda up to your own on that one being as though thats a different size than stock and the tire will give its max PSI only. your 4runner doesnt come close to the tires max load so you dont want to run the tire at max PSI or you will get undesirable wear. i would recommend staying between 35-40PSI and just doing some "seat of the pants testing" to see how you like it best by feel, along with tire wear, MPG and how it handles... thats how i set my tires, -every tire is differant from one brand to another and your particular driving habits and style will have to factor in as well. i have an older 85 toyota 4x4 pickup that im running 33 12.50s on and only run the tires at 23PSI up front and 19-20PSI in the rear, just cause that truck is so light(tire says 50PSI max), i feel it gets the best traction that way and i have no adverse tire wear from going that low, and i dont care about MPG cause its not a DD.

 

[bike]

A similar question came up on my local forum. Luckily some guys are pretty knowledgeable (with one of them working at a tire shop), so I'll post it below.

Q: If a d class tire is rated at say 3100 lbs and an e rated tire in same size is same weight rating but difference being max psi bring 50 and 65 respectively,
What does all that mean?

A: What that means is this; because an "E" rated tire has a heavier construction (old school 10 ply), it takes more tire pressure to inflate the structure so that it can carry the same weight as a "D" load range tire (old school 8 ply). also note that if you are upgrading your "P" rated stock tire to a "D" or "E" load range tire please raised your daily operating pressure so your truck can carry the same weight as the OEM tire and handle safely. eg: P265/70R17 @ 32 psi - upsize to "E" load range, you should run 47 psi to carry the same load.

A: Dude, I would suggest going to a tire shop and asking to see the TRA (Tire and Rim Association) book. It'll have all the load inflation tables and calculations to figure out what you need to be running for your stock weight and oversized tires. Then you can approximate what you'll need for your overloaded weight and oversized tires.

I still don't understand it all myself. Hopefully soon once I get my truck out of stock form I'll look into it a bit more but right now this is as much as I can help.

 

[MTDewX8]

I have some Duratracs 265-75-16's c load range
and new the gave me 41psi out the door.

first road trip burned the middle up a bit.
so now I am running 32 front and back. might even drop to 30 0r 31.

its trial and error, just keep an eye on your wear and adjust accordingly
there is no set psi except what YOU like and see wearing

 

[fightman80]

My Bighorns say to inflate to something like 60 some odd lbs....i tried that...and the truck felt like it was on roller skates! I lowered it back to about 35lbs and the ride is much better! The tires even seem to soak up some of the bumps in the road.......

 

[tinman]

I always just do the seat of the pants measurement. Seems like most tire stores set me up around 40-45 psi when I get tires & wheels mounted. I typically like to run 30-35 though for my likings. In the end, it's all about preference. As long as you don't run something silly like 15-18 lbs, that is.

You could do the chalk/crayon test. Mark a line all the way across your tire tread contact patch with chalk or crayon, about 1" wide. Then drive forward in a straight line for about 20-25 feet. Look at the chalk/crayon results. If the middle is worn more than the outside, drop the pressure a bit. And if the outside is worn more than the middle, bump up the pressure a little.

All that said, I still go by what feels the best for ride and tire wear.

 

[IFNg]

Use the chart to cross-reference and find the corresponding PSI, then adjust if there's any wear issues

 

[Atreyus]

Use the chart to cross-reference and find the corresponding PSI, then adjust if there's any wear issues

Based on that chart Mine should be at 32 PSI then right now I'm at 35 PSI and I felt the ride was good coming down from 40 PSI. I'm just glad I was closer to the correct number lol. Thanks for all the info guys!

 

[JB.]

33" BFG A/T KO tires? It says 50 psi max, I have mine at 35 right now is that recommended? Anyone know the proper inflation? Or where I can look for the correction info?

The standard method is to establish how much load reserve the OE tire had and then inflate the new tire to that load reserve. Assuming the stock tire was P265/70/16 and the door sticker recommended 32psi, that load capacity is about 2115lbs. If no change in tire size occurs, nothing changes. If you change tire size (and moving from P to LT qualifies as a size change even if the LT tire is has the same dimensions -- ignore load range) then you need to find out what psi in the new tire gives you about 2115lbs of load carrying capacity. If the LT tire is the same "size" as the P, then an easy rule of thumb is 10-15lbs extra. If the new tire is bigger, it will require less. You didn't give the dimensions of your tire but you can look it up in the table linked in this thread.

LT vs P inflation article - Toyota 4Runner Forum

 

[JB.]

A similar question came up on my local forum. Luckily some guys are pretty knowledgeable (with one of them working at a tire shop), so I'll post it below.

Q: If a d class tire is rated at say 3100 lbs and an e rated tire in same size is same weight rating but difference being max psi bring 50 and 65 respectively,
What does all that mean?

A: What that means is this; because an "E" rated tire has a heavier construction (old school 10 ply), it takes more tire pressure to inflate the structure so that it can carry the same weight as a "D" load range tire (old school 8 ply). also note that if you are upgrading your "P" rated stock tire to a "D" or "E" load range tire please raised your daily operating pressure so your truck can carry the same weight as the OEM tire and handle safely. eg: P265/70R17 @ 32 psi - upsize to "E" load range, you should run 47 psi to carry the same load.

No, the load E and the load D carry the same load at the same psi. The only difference being that when the load D reaches its max psi (and thus max load capacity) the load E can continue to take more pressure (and more load).

He's right about going to 47psi from 32psi, but stating it in terms of load range causes endless confusion. It's simply a consequence of changing from P to LT, regardless of load range.

And I'll get on my soap box here. Tire Rack contributes to this confusion in no small way by continuing to omit the P or LT in tire size prefixes which creates the illusion that tire selection is simply a matter of choosing a preferred carcass thickness from a symmetrical ladder scale. It's not true. Going to LT (regardless of load range) from P, while changing nothing else, results in a sharp reduction of load carrying capacity.

 

[Atreyus]

This is my tire size.
33X10.5R15
114R C
max load 2600 lbs.

 

[JB.]

This is my tire size.
33X10.5R15
114R C
max load 2600 lbs.

Given my assumption about the OE tire then 38psi if you want to cut it that fine, but if you like 35, I see no reason to change.

 

[Atreyus]

Thanks for the info JB.

 

[Elton H]

ya never go by what it says on the tire 35 is what alot of people run

 

[CanukRunner]

I have specially desinged rims and tires from toyota research and development department...


They cost lots extra though... they automatically deflate to 20 psi after a week 15 psi after 2weeks... lol

Its nice because there is no need to use any charts to figure out how much psi to keep in them... they always go back down to 20..lol