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Discussion Starter · #1 · (Edited)
I have almost 1,000 miles on my new tires (BFG KO2 LT275/65/18). I went from a P to LT because of the TT. I am still trying to figure out the proper psi. I have found numerous resources with just as many opinions.

I have read if you stay with the stock size tire you should continue to use the door sticker even if you switch to a LT.

On the BFG website I found a spot that states 40psi for my truck with that tire.

I also emailed BFG customer service and received a reply today. They stated 55psi.

I have also also performed the chalk test and found anywhere from 36psi to 44psi to be the correct pressure.

I am obvioulsy crazy and over analyzing, but what do you think? I have been at 42psi for the past two weeks and can't complain. Do you think 42psi is under inflated, therefore inducing the tire to run at a higher (possibly dangerous) temperature? Sorry for being a nut!
 

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Tire shop that put my 285/70R17's suggested 55psi min for unloaded.

White Line Rectangle


BFG website says 80 psi for max load for your tire size.
 

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Running 44 cold in mine and that jumped up to 47-48 while warm/hot on a trip and 70 degree weather.
Just ran 550 miles round trip to Philly and a hand calculated 17.9mpg with a corrected speedo via SCT.
 

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I'm running 275/65r20's so not quite the same but anything less than 42psi and it they have noticeable bulge. I can't imagine running at 55 psi all the time though, ride would be jarring. I do air up the rear tires when towing heavy but don't leave em that way. so I run 42 psi cold since it's the lowest psi (comfort!) that doesn't cause abnormal wear that I can tell
 

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I'd think 42 to 44psi would be a good starting point for daily driving. Each truck is different so a little experimenting may be necessary!
 

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I emailed BF Goodrich and they said if using stock size to inflate KO2 tires to the manufacturer's placard pressure. 35 psig? Are they kidding me??? That would be too low.
What size and load rating? Mine are the 34x10.50r17 load D and 35psi is perfect
 

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42 in my KOs seems good to me, when towing I bump the rear up to 75 cold fronts maybe 70 cold.
An old trick to see if the tire is set to wear right is to take chalk and color a stripe across the treads a few inches wide. Then drive the truck forward a couple of revolutions of the tire, check the wear pattern in the chalk.
Chalk wears in the middle= too much air, on the edges =too little air
 

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Discussion Starter · #11 ·
I emailed BF Goodrich and they said if using stock size to inflate KO2 tires to the manufacturer's placard pressure. 35 psig? Are they kidding me??? That would be too low.
Too funny. They responded to my email the other day and said 55psi. I actually referenced my research and straight up asked about stock size and the door sticker and they flat out said no, it needs to be 55psi. Unreal. What a joke.
 

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275/65/18 and they will need to be E rated since D is not in that size.
Ya, was just saying what my size takes.

Edit ;Which are D load with Max psi of 65
 

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I have KO2's in size 275/60/20 and was running them around 35 PSI from the installer which I left like that through winter..But just a week ago I decided to set them at 50 PSI and noticed a quieter ride and yet still very smooth.I notice better mileage as well.Obviously in snow or ice less pressure is probably better but I'm liking the higher pressure with mine 2012 FX4 Screw 5.5 bed
 

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I just called the BF Goodrich Canada contact number to ask them about pressure. For my 2011 screw cab 5.5 foot box ecoboost xtr, the stock size is p275/65r18. I'm going up to lt275/70r18 in the KO2's. They asked me to confirm the stock size on the placard, then put me on hold for a minute, then told me 50psi all the way around for the new KO2's.

I believe that to be true as well from all the research I've done on forums and reviews. Some people got duped into sticking with the stock size tires pressure (which doesn't make sense because this is a 10 ply e rated tire, not a low quality smaller factory p tire). Others seem to have gotten mixed answers. From what I gathered 43-45 seems to be the minimum people run for this size using chalk tests and taking into consideration mileage and ride quality.
Others run it as high as 55-60 depending if they are towing a bit or if they want a stiffer ride/slightly better mileage.

Im going to start with what they recommend then maybe try a chalk test and maybe adjust slightly.
 

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Got an oil change on Sunday, they set all 4 @ 50 with my 10 ply BFG.

Tire shop originally set them @ 55. I cant tell the difference.
 

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Discussion Starter · #18 ·
Contacted BFG again and at least they gave me the same story twice. They recommended 55psi again. I also had a chance to stop over at Discount Tire (they are a big chain out here) and in their computer it says 41psi (they told me to add 10% on top because we are at altitude). I am going up to 48psi for now. Thanks for all the responses.
 

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I just put on LT275/65R20 K02 tires and the shop set them at 40 lbs. By the next morning they were 35 lbs. I thought there must be slow, perfectly even leaks, but the weather differential was 40 degrees. 69 degrees when installed versus 29 degrees the next morning and I guess it does change pressure that much. I'm planning to do the chalk test at different pressures.
 

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35 when cold are perfect unless hauling heavy or towing with a heavy tongue weight. I would start st 50 in that case.
 
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