LT Tires and Running Lower Pressure

[Boyk1182]

I understand load ratings and proper pressures for hauling, towing, etc. so I will adjust accordingly in those situations.

My tires are BFG KO2 and the size is LT295/65R20, load range E tires.

My question is for daily driving. If the chalk test shows that they will wear well at a pressure lower than recommended by BFG and the LT tire conversion calculator, and even lower than the door sticker, is it safe to run them like that for daily driving? I did the chalk test and they’re pretty good at 36 psi but still making more contact at the center of the tires so likely overinflated at that pressure while unloaded. Thanks.

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[v8440]

My opinion is that it is safe. I run load range E tires on my two dodge diesels, one a 2500 and one a 3500 dually, and I only run the fronts at 80 psi. The rears on both trucks get less pressure, lower on the dually than the 2500, and the tires wear pretty evenly. The rears do wear out in the center faster if I run the full 80 lbs in them.

 

[Boyk1182]

My opinion is that it is safe. I run load range E tires on my two dodge diesels, one a 2500 and one a 3500 dually, and I only run the fronts at 80 psi. The rears on both trucks get less pressure, lower on the dually than the 2500, and the tires wear pretty evenly. The rears do wear out in the center faster if I run the full 80 lbs in them.

The whole thing that brought this up is trying to get better compliance from the rear. I have added a Steeda sway bar and Fox shocks, so it’s a lot better, and I’ve been wondering about lower pressure there as well. How much lower do you run the rears than the fronts?

 

[v8440]

I think I run the rears on the dually at about 40 lbs, and the rears on the 2500 at 45 or 50. I run the fronts at 80. The front end of my 2wd dually has more than 2000 lbs on each tire, so I'd assume the 4wd 2500 with the same engine is even heavier. What's the max pressure printed on the sidewall of your tires? I'm surprised to read of load range E's being used on a 1/2 ton anything, to be honest.

 

[Boyk1182]

I think I run the rears on the dually at about 40 lbs, and the rears on the 2500 at 45 or 50. What's the max pressure printed on the sidewall of your tires? I'm surprised to read of load range E's being used on a 1/2 ton anything, to be honest.

The max pressure for the tires is 80 psi, but of course I’d never run that. I didn’t necessarily want E rated tires but to get the size I wanted I didn’t have much choice. I do like the strength of them but not the weight.

 

[v8440]

On a side note, I bet that platinum powerboost is a nice truck.

 

[v8440]

The max pressure for the tires is 80 psi, but of course I’d never run that. I didn’t necessarily want E rated tires but to get the size I wanted I didn’t have much choice. I do like the strength of them but not the weight.

Makes sense. I bet they ride like a conestoga wagon compared to more normal tires for the truck, the sidewall in mine is pretty stiff.

 

[Boyk1182]

Makes sense. I bet they ride like a conestoga wagon compared to more normal tires for the truck, the sidewall in mine is pretty stiff.

They definitely don’t ride like the day I bought it.
Here’s the chalk test, first picture is the front tire and it looks like I got that dialed in. The second picture is the rear and it’s close, but I may try a lower pressure on those. I don’t know if I want to deal with all that though so I may just leave it like this for a while.

 

[v8440]

Yeah, I would expect the rears to need less pressure (unloaded) than the front.

 

[HammaMan]

I run 41f 39r unloaded. PIggyboost is pretty heavy. If you compare other trucks w/ LT tires and their weights/pressures against the weight charts, you'll see much higher pressures with warnings about LT tires needing more air pressure. Given the number of lighter trucks / jeeps running even less pressure and no issues, appears okay. Another thing to look at is the witness marks on the front tires to see if they're rolling under in turns.

 

[Boyk1182]

I run 41f 39r unloaded. PIggyboost is pretty heavy. If you compare other trucks w/ LT tires and their weights/pressures against the weight charts, you'll see much higher pressures with warnings about LT tires needing more air pressure. Given the number of lighter trucks / jeeps running even less pressure and no issues, appears okay. Another thing to look at is the witness marks on the front tires to see if they're rolling under in turns.

If I drop the rears I was thinking 2 psi like yours. I bought a measuring tool today and everywhere I measure is within 1/32” so no abnormal wear, and that has been at 38 psi for a few thousand miles. I’m going to try 36 for a while because the chalk test showed that may be better, but I’ll track the inside and outside wear with that tool and see how it goes.

 

[CoolCoyote]

I have zero input but the chalk test intrigues me, so thank you for that. I've never heard of it before.

 

[Boyk1182]

I have zero input but the chalk test intrigues me, so thank you for that. I've never heard of it before.

Check out a YouTube video, it’s worth the few minutes that it takes to see if you are running the right pressure.

 

[Calson]

Always use the Ford recommended front and rear tire pressures. With my F-150 it is 35 PSI for all tires. With my 2500 class tire I used 55 at the front and 55 at the rear with the bed empty and 80 PSI at the rear when carrying a heavy load in the bed.

This provides maximum tire tread life, the best handling on pavement, and the least risk of an overheated tire blowout.

The tire manufacturers' charts are worthless and dangerous. Many examples of accidents and deaths as a result.

 

[Boyk1182]

Always use the Ford recommended front and rear tire pressures. With my F-150 it is 35 PSI for all tires. With my 2500 class tire I used 55 at the front and 55 at the rear with the bed empty and 80 PSI at the rear when carrying a heavy load in the bed.

This provides maximum tire tread life, the best handling on pavement, and the least risk of an overheated tire blowout.

The tire manufacturers' charts are worthless and dangerous. Many examples of accidents and deaths as a result.

That is true for similar load capacity tires, but if you switch from P metric or regular metric to LT, it is not always the same pressure to achieve the same load carrying capacity. This calculator is good for making the conversion with all variables accounted for:

https://tiresize.com/pressure-calculator/

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