KO3's!!!

IIRC, under inflated tires, will cause excessive wear on the side walls, and heat up the tires when running at interstate speeds. Maybe an infrared thermometer would help you detect excessive heat build up in the side walls. If you find tiny little rubber balls inside the tire when they are changed down the road, they were probably run in an overheated state at some time.
 
Buckfever said:
BFG does not have the 2024 Land Cruiser in their data base and could not provide guidance on tire pressure.
Click to expand...
Keep an eye on tire temps as I mentioned above. Under inflated E series will over heat the sidewalls, and can cause catastrophic tire sidewall failure.
 
MPG hit with (275s) KO3 might be exaggerated. I’m getting 21-23 when I’m gentle and in eco. 19 when I drive it like it’s for fun.

I will probably still be returning the KO3 to DC though as the ride is way less nice than my KO2s on my Taco were. I still think it’s possible I have a defective batch but I’m tired of driving to town for balancing and shit. Probably going back to an SL AT.
 
Buckfever said:
OK so LCColorado got me thinking. I looked up the load index on the KO3's for my tire and it's 3197 the load index on the stock LTX trails are 2756. So then it becomes a simple math problem. 3197 divided by 2756 times the recommended 33 psi which gives you 38.28 PSI for the K03's in the stock size.

However for many sizes of the KO3's the load index is 3525 so for those tires the math comes out to 42.2 PSI.

I'm still going to reach out to BFG.
Click to expand...
I'm curious to know where you came up with the idea to take the ratio of the load index to determine the proper pressure to run the tire. Can you point me to the source? I also look forward to hearing what BFG says about the inflation pressure vs. Toyota's recommended inflation pressure. The stock tires on my LC were over-inflated to 38 psi when I took delivery. Reducing the pressure to the recommended 33 psi on them (I have the 265/60R20) improved the ride of the car substantially. The load index on the stock 20" tires is 2469 (x 4 = 9876 lbs).
 
uraniumrich said:
I'm curious to know where you came up with the idea to take the ratio of the load index to determine the proper pressure to run the tire. Can you point me to the source? I also look forward to hearing what BFG says about the inflation pressure vs. Toyota's recommended inflation pressure. The stock tires on my LC were over-inflated to 38 psi when I took delivery. Reducing the pressure to the recommended 33 psi on them (I have the 265/60R20) improved the ride of the car substantially. The load index on the stock 20" tires is 2469 (x 4 = 9876 lbs).
Click to expand...

ultane said:
Yea, me too… 🤔 That concept is new to me.
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So there's a lot written about this in the internet. I didn't keep track of all that I've read

This is one source though Tire Pressure Calculator
 
ultane said:
Keep an eye on tire temps as I mentioned above. Under inflated E series will over heat the sidewalls, and can cause catastrophic tire sidewall failure.
Click to expand...

You're making me nervous for sure. I may bump it up a little till I have better answers.
 
mayonayze said:
Anybody tried this size on the stock 1958 wheel?
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Yes. Seeing about 2 mpg lower than the stock tire (and adding Prisu rack). Interesting thread about tire pressure. Mine are at 37psi and I’m still getting used to them. Just waiting for it to snow.
IMG_3943.jpeg

IMG_3941.jpeg
 
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I had KO3s installed on the Toyota rims about 10 days ago. I drove 50 miles home and the ride was terrible. Way too much vibration. Checked the PSI and all five tires were at 40psi. I added air to bring them up to 47-50 range and now the ride is perfect and no vibration. Love the tires.
 

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BabyHughey said:
I had KO3s installed on the Toyota rims about 10 days ago. I drove 50 miles home and the ride was terrible. Way too much vibration. Checked the PSI and all five tires were at 40psi. I added air to bring them up to 47-50 range and now the ride is perfect and no vibration. Love the tires.
Click to expand...
How harsh is the cabin when psi is that high?
 
So another update. I went ahead and increased the pressure to 42 psi although not sure how cold the tires were, only waited about 10 minutes.

So I noticed that on the Lexus GX 550 Overtrail the tires on the 18s have the same load rating 2756 as the FE, sooo I reached out BFG via email and asked what the tire pressure should be if fitted with the KO3s in the stock size on the 550. Since they have that vehicle in their database that should give us an answer. And if I have time I'll go on the chat tomorrow and see if I can get a answer sooner.
 
I just can’t un-see the tiger-stripe pattern on the shoulder/sidewall of the new KO3s. Reminds me of the Cincinnati Bengals uniforms.
 
BFG responded via chat that for the Lexus GX 550 Overtrail, the recommended pressure for the KO3 265/70/r18 is 50 PSI. I believe the placard states 35 PSi which is 2 more than the placard on my FE. Doing the math that would be 47 cold on the FE, which is where the dealer set it when they changed out the tires.

To me that seems high but that's what they said.
 
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OK so I did some more reading and believe I figured it out. "When a P-metric or metric tire is installed on a light truck (SUV, pickup, minivan), the load capacity of the tire is reduced by a factor of 1.10 as prescribed by the Federal Motor Vehicle Safety Standards(FMVSS). For example, 305/50R20 has a maximum load capacity of 3086 lbs. If this tire is fitted to alight truck, then the actual allowable load capacity for the tire is 2805 lbs. (3086 lbs. divided by 1.1)"

So the OEM tires 2756 load capacity needs to be reduced by a factor of 1.1 which is 2505.45.

There are 2 numbers for load capacity on the KO3s in the stock size. "Light truck tires have two load rating numbers because they are often used on vehicles with dual rear wheels. The first number is the load rating when the tire is used alone, and the second is the rating when it is used as a dual tire"

I was using the second number, I need to use the first number which is 3527 for the KO3 in the stock size.

So that math is: 33*3527/2505.45 = 46.5 PSI


Refererences:

www.sullivantire.com

Tire Load Index | Sullivan Tire & Auto Service

What's a Tire Load and why is it important? Sullivan Tire and Auto Service has the answer! Head over to out Tire Classroom to learn more.
www.sullivantire.com www.sullivantire.com
 
Brought the psi to 49 hot we'll see in the morning what it is cold. Ride quality was not horrible but we didn't test with the railroad tracks. Tomorrow.

Feels even more solid, stiffer, less roll. If this is what it is supposed to be, I'll get used to it.


MPG has been down to 20.4 for a couple days now.
 
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