Interesting - KO2 Tire Pressure per BFG site

[DAW89446]

I recently replaced the OEM rubber on my ‘18 SR5 with BFG All Terrain T/A KOs as well. I had load range E spooned on in OEM size. I also saw the recommended 44psi pressure on BFG’s website. My tire dealer also pressurized them to 44. So far I’ve kept it there, and haven’t noticed any real differences in ride or tire impact due to rough surfaces. I asked the installer about this and he said he thinks they would do fine with lower pressures on the street.

On my previous 2002 Tacoma TRD I also ran two sets of BFG’s in OEM size (LT265/70R16), also load range E. The tire dealer always aired them up to 35psi for the road and I found altering that pressure brought on negative wear and ride issues. Never had any wear issues at 35. Always lowered pressures on the dirt, usually 16-20. Not sure of weight specifications between the Tacoma and my 4Runner.

EDIT: Just Googled and found my Tacoma weight roughly 3515#; my 4Runner roughly 4500#.

 

[the_economist]

Ditto, same tire size and running 40 PSI feels like the sweet spot for both wear and driving comfort on pavement.

Same here: I ran 265/70-17 C-rated KO2s at ~38 PSI for 30K miles, and got even wear and great driving performance on highway. Now I'm running 275/70-17 E-rated KO2s at 40 PSI, and am getting almost the same feel on the road.

 

[Jivewalker]

Same here: I ran 265/70-17 C-rated KO2s at ~38 PSI for 30K miles, and got even wear and great driving performance on highway. Now I'm running 275/70-17 E-rated KO2s at 40 PSI, and am getting almost the same feel on the road.

I looked it up yesterday and there is a difference in the 265 vs. 275 load rating/inflation. I believe the 275 landed between 35-40psi and the 265 was at 44psi. I linked the Toyo load tables / instructions in a post above. It seems to agree with BFG pressure.

 

[ChrisJHarney]

Funny, I was getting inside hi lo feathering wear on the fronts

Inside feathering is more commonly associated with negative camber wear than tire inflation. I had to get several alignments over the life of my KO2s.

 

[Jivewalker]

Inside feathering is more commonly associated with negative camber wear than tire inflation. I had to get several alignments over the life of my KO2s.

Agree 100%, just had the alignment done as well as tires re-balanced. I wasn't very far out, at least existing vs. corrected. I'll post what they were later. I don't know what correct numbers look like, just if they are green, yellow, red. guess I need to read up on that.

I could tell from feel that 32 was to low. I could feel and hear the stress on the diffs and transmission (vibrations, bearing noise) and the tires were warm/hot, which I though was normal. at 40, I'm not feeling the stress (vibrations, bearing noises) as much if at all.

 

[mbumpus11]

I toyed with 40psi, and 38psi initially, but now run 43psi in my 275/70/17's and have been very pleased with mileage/wear/noise, personally. To me, 38 was way too spongy, and 43 seems to be my sweet spot for efficiency's sake.

Last fill up I topped 18.1mpg of about 80% hwy/20% city for that tank. Might've had a slight tailwind on the highway as I usually see high 17.X's mpg on the same stretch, but could've done better with cruise instead of aggressive passing that day

When off road if I air down at all it is no lower than 36psi, but even then that is IF I air down. Most times I don't and have no problem driving in/out of ranch roads, river roads, and muddy surfaces.

 

[mogg851]

I was also surprised when I ran into another thread about this with the KO2s. I found 40ish to be good.

I installed an aftermarket head unit which shows me PSI and temp in 10sec updates. I found that after I've started airing down (sometimes 18psi or lower for snow) and airing up again, not having the nitrogen fill makes PSI fluctuate ~2PSI up or down for every 10Deg. F in temp change. So if I fill to 38 at 40F when it was cold, but the time the tires heat up either from sun or driving I'm at 42 or so by the time my tires get up to 70.

On pavement 40-42 feels stiff, but handles well and I'm pretty sure helps with the milage. I remember when I first got the KO2s I thought someone at Costco messed up and deflated back to 32 and immediately noticed it felt very mushy and unstable, even at street speeds. I guess the point is that while there is an optimal PSI, you will still have SOME variance between temp, road conditions, weather, elevation, etc.

 

[deadbeat son]

Sorry if this was already posted. I've been reading the tire pressure threads, well a lot of them, and I decided to go to the BF Goodrich site and was surprised by the disclaimer right on the page for my stock tire size. It says clearly that I need to raise my inflation pressure to 44psi. I have been running 32psi. Don't remember ever seeing this before when I bought my tires many miles ago. Check it out.

All-Terrain T/A(R) KO2 | BFGoodrich Tires

Awesome, I'm validated! I installed 265/70-17 AT-KO2s with 118 miles on the odo, and I had them inflated to 44psi. I had hand calculated the change from SL to LT-C using tire load charts. That was about 4500 miles ago, and I don't see any abnormal wear on the tires.

 

[Ryan1975]

Lowered mine to 10psi for last March’s Bomb Cyclone

 

[Jivewalker]

I also think there is some thought that needs to be put into whether LT tires are the right choice. If you think about it, the higher psi gives a harsher ride and more jarring and wear on suspension components. Is it wort the trade off if you don't also upgrade the suspension to handle the increase in harshness? Or, is it better to get some beefy P rated all terrains, if they even exist. Then you could have the more flexy cushion of air between the trail/road and the suspension? Maybe its all bullshit piss ant stuff and I'm overthinking it, but it does make some sense. 40 is doing great for me right now with the KO2's, would love to slap some P rated tires back on at 32psi just to see the difference. I may even take the KO2's up to the recommended 44psi just to check it out like others have.

 

[Jivewalker]

Lowered mine to 10psi for last March’s Bomb Cyclone

Don't like seeing that your 2012 tE is gone! But glad to see it's not forgotten! Love mine, Black Betty rocks on with 182k so far!

 

[DAW89446]

I also think there is some thought that needs to be put into whether LT tires are the right choice. If you think about it, the higher psi gives a harsher ride and more jarring and wear on suspension components. Is it wort the trade off if you don't also upgrade the suspension to handle the increase in harshness? Or, is it better to get some beefy P rated all terrains, if they even exist. Then you could have the more flexy cushion of air between the trail/road and the suspension? Maybe its all bullshit piss ant stuff and I'm overthinking it, but it does make some sense. 40 is doing great for me right now with the KO2's, would love to slap some P rated tires back on at 32psi just to see the difference. I may even take the KO2's up to the recommended 44psi just to check it out like others have.

I considered if 10 ply E rated tires were overkill, vs. 6 ply C rated. But two things swayed me 10 ply. A. Price. There was little difference in price between the two as quoted by my local dealer. And B. Dirt roads and trails. Where I live, miles and miles of maintained are regularly used. When hunting and off roading for pleasure, there is lots of decomposed granite, sharp bedrock and other obstacles.

Since the 4Runner is relatively heavy, the better value for me is an E rated tire.

 

[Ryan1975]

Don't like seeing that your 2012 tE is gone! But glad to see it's not forgotten! Love mine, Black Betty rocks on with 182k so far!

2016 with 107k

 

[AK Mule]

Thank you

This is one of the most informed threads on tire pressure I have seen in a lot of years on any forum. I have applied some of the information here to other cars and trucks we have. Some of my thoughts:

1. Switching from "P" tires to "LT" tires is a significant difference in tire loads and capabilities. The door jam sticker is no longer relevant, even if you use the same size tire. If you change tire size or brand, more math and experimenting/guesswork is needed.

2. We changed out the 20 inch wheels and tires on our Limited for SR5 wheels and stock size tires, but kept "P" tires, so the door jam is still mostly relevant. Summer is "P" Bridestone and winter is "P" Blizzak. So, about 32 to 34 PSI. We have not changed to any "LT" tires...yet.

3. Here is the biggie: Regardless of the tire we use, temperature is very important along with load range. When I set my cold tires' pressure in my 60-degree garage at 32 for "P" or 44 for "LT", that is fine for now. Then I open my garage door and leave, and the temperature may be 50-70 degrees colder outside (I'm in Alaska). If I am driving in town, they stay very cold (or after work outside). If I get on the highway, they probably warm up some. Rule of thumb is lose 1 PSI for each 10 degrees of temperature. Take that into account when you set your tire pressure if Summer and Winter are very different. After being at work all day in winter, my 32 PSI is probably a lot lower when I hit the road.

I set my "P" tires for 32 PSI in the Summer and 38 PSI in the winter. If I had "LT" tires, I would set them around 40 PSI in Summer and 46 PSI in Winter.

 

[jhguth]

What are you over inflating them in winter, that seems almost opposite of what you would want

 

[AK Mule]

What are you over inflating them in winter, that seems almost opposite of what you would want

Because at negative 20 degrees outside, the pressure quickly drops to where it should be or lower. I set the PSI in the garage; I drive outside. From my garage to the outside can change the pressure almost 10 PSI down.

 

[1jzgte]

What are you over inflating them in winter, that seems almost opposite of what you would want

The guy lives in AK

 

[Garwel]

FYI and FWIW I went to the BFG website and hit the chat with us icon and had the following conversation:

Porter T (10/24/2019, 2:53:15 PM): Hello, I'm Porter How Can I help you?
(10/24/2019, 2:54:04 PM): for All-Terrain T/A® KO2 your site says a pressure increase to 44psi but my 4runner manual says 32, which do i use ?
Porter T (10/24/2019, 2:55:38 PM): Use the 44 PSI. Since the KO2 is a bigger tire, it will require more air. the vehicle most likely came with a P metric, smaller tire thus the lower PSI. But since you changed to LT, thus you raise the PSI.
(10/24/2019, 2:55:52 PM): ok ty

 

[AK Mule]

FYI and FWIW I went to the BFG website and hit the chat with us icon and had the following conversation:

Porter T (10/24/2019, 2:53:15 PM): Hello, I'm Porter How Can I help you?
(10/24/2019, 2:54:04 PM): for All-Terrain T/A® KO2 your site says a pressure increase to 44psi but my 4runner manual says 32, which do i use ?
Porter T (10/24/2019, 2:55:38 PM): Use the 44 PSI. Since the KO2 is a bigger tire, it will require more air. the vehicle most likely came with a P metric, smaller tire thus the lower PSI. But since you changed to LT, thus you raise the PSI.
(10/24/2019, 2:55:52 PM): ok ty

The "P" to "LT" is correct, and a bigger tire will hold more air. More air (volume) is not more pressure, though. Actually, a bigger tire can have a larger load rating at the same pressure. It has more air (volume) to hold up the weight, and doesn't always need more pressure, if they are both "P" or both "LT". In this case, switching from "P" to "LT" is the reason for the pressure increase.

If you went from one size "LT" tire to a larger "LT" tire, you could decrease the pressure and have the same load rating because you have more volume. Volume is constrained by the size of the tire, pressure is not. Volume holds up the truck, not just pressure.

 

[YotaMD]

Something interesting that came to light recently on my partially armored 100 series (around ~400# heavier than a 5th gen 4R) is that the KO2s at recommended 44 psi are noticeably harsh for my wife. She kept getting car sick on medium to long trips and then suddenly was better on our way home from a trail run where I only aired up to ~32 psi. Tires were more noisy, but my wife was totally fine.

I tested it a few times after where I'd modify the pressure without telling her and see if she noticed. I thought it was a placebo effect or something. I was wrong, she could tell every time I raised pressures and never complained with pressures set lower.

I would have sworn there was no perceptible ride quality difference between the E rated KO2 and my other tires, but my wife has proven otherwise...

I now run my KO2's at around 33psi. Happy wife, happy life.