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Optimal psi for 285/75R16 tires?


Vtx531

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The lowest pressure on the load/inflation tables for LT tires is 35 psi and shows 2130lb (per tire) for that particular size.

Additionally, it is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.

Anything less than 35psi is a guess but a lot of people here are comfortable with that.

A radial tire will not wear out in the center of the tread if it is “overinflated”.
 
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Mudflat

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The lowest pressure on the load/inflation tables for LT tires is 35 psi and shows 2130lb (per tire) for that particular size. It is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.

Anything less than 35psi is a guess but a lot of people here are comfortable with that.

A radial tire will not wear out in the center of the tread if it is “overinflated”.
I must respectfully disagree. A radial tire, like any other tire, will wear sooner in the center of the tread if it is significantly overinflated. I have observed this on dually pick-ups owned by some of my RVing friends who insist on running 80 psi in their dual rear tires that are rated load range “E” because that is what’s on the sidewall of the tire. This is a dangerous condition, not only because of the reduced contact patch, but because that patch is becoming more & more slick with wear.
I ran 65 psi in my dually tires, both towing & solo, as recommended on the door jamb placard with no abnormal wear on the treads. The tires didn’t “squat” under load and the temperatures were normal as checked with an infrared thermometer.
 

rouxbicon

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The lowest pressure on the load/inflation tables for LT tires is 35 psi and shows 2130lb (per tire) for that particular size.

Additionally, it is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.

Anything less than 35psi is a guess but a lot of people here are comfortable with that.

A radial tire will not wear out in the center of the tread if it is “overinflated”.
A 285/75R16 is almost certainly going to be an E rated tire. Running 35 psi installed on a typical TJ will contribute to a harsh ride. I have run my LT 285/75R16 Goodyear MTRs at 27 psi for several years now with never a problem. And I think some here on the forum might suggest even 1 or 2 psi less...E rated tires on a TJ are never going to contribute to a smooth ride, but there's no point in making it worse with unnecessarily high pressure
 

Paulstanfill85

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In my 31s I run 30PSI. Tire pressure is dependent upon load as others have stated. There are actually calculators available online using GVWR to determine in theory what pressure you should run.
 

JMT

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Hey fellas,

I'm running 285/75R16 size tyres. What's the optimum psi I should be running?

All input is appreciated. Thanks
Optimal for your metric equivalent of a 33” tire is 26psi. I just ran my Cooper STT Pros at 26psi for 28,474 miles and the wear is even across the tire. Still have 8-9/32’s on 3 tires and 10-11/32’s on 2 tires.
 

CodaMan

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The lowest pressure on the load/inflation tables for LT tires is 35 psi and shows 2130lb (per tire) for that particular size.

Additionally, it is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.

Anything less than 35psi is a guess but a lot of people here are comfortable with that.

A radial tire will not wear out in the center of the tread if it is “overinflated”.
I totally disagree. I run those tires (E rated) at 26 psi. They are fairly smooth for the load rating and the wear has been nice an even.
 

Jerry Bransford

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The lowest pressure on the load/inflation tables for LT tires is 35 psi and shows 2130lb (per tire) for that particular size.

Additionally, it is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.

Anything less than 35psi is a guess but a lot of people here are comfortable with that.

A radial tire will not wear out in the center of the tread if it is “overinflated”.
Whatever "table" you're looking at, it's either wrong or you're misinterpreting it. And YES you absolutely go with a lower air pressure when going with larger tires. Which is one reason skinny road racing bike tires require high pressures like 120 psi yet big fat balloon beach cruiser bike tires require 1/4 that pressure. And look at the sticker on the door jambs and notice how the recommended pressures vary by tire size with larger sizes requiring lower pressures. Standard Wrangler factory size tires require 31-33 psi but 35" tires only require 24-26 psi. The bigger the tire the less pressure it requires to support a given weight. And visa-versa.
 
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Mr. Bills

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. . . it is not recommended to go lower than the stated door pressure even if you are going to a bigger tire.
Not recommended by whom? Even BFG customer service will give you lower pressures than the pressures on the door placard if you tell them you are "upsizing" from the stock tire size for your vehicles.

Actually, it is typically recommended by nearly every experienced offroader and offroad vehicle outfitter to run lower pressures than originally specified by the manufacturer when going to larger than stock tires and has been for 60 years if not longer.*

Then there is this:

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


I'm running 285/75R16 size tyres. What's the optimum psi I should be running?


A 285/75R16 is sometimes referred to as a "metric 33."

Although the "optimum" pressure may vary depending upon the particular tire, actual weight of the jeep, etc., is it generally recommended to run 26 psi with that size tire on a TJ. If your jeep is fully loaded, equipped with heavy body armor, etc., you might experiment with 28 psi.

It will take a bit of experimentation to find the "optimum" pressure for your tires and your jeep.



__________________________________
* I count nearly 60 years from the time that Dick Cepek, one of the first to bring flotation tires to the offroading market, taught that lesson to me as a teenager while accompanying my father to buy a set of tires from Mr. Cepek when he was still operating out of his one car garage in South Gate California.
 
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Vtx531

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Okay, to make everyone here happy: Just pick a tire pressure that start with a 2 as the first digit and call it good.
Recommending 35 psi and anything other is basically nonsense and not backed by reality.
Your disagreement is with the Tire and Rim Association and their manuals not me.

If you want to deviate from recommended procedure (which is fine) then it would be good to at least know what the recommended procedure is first.

I already said lots of people here are comfortable running less psi than recommended and I am not questioning that. Need to chill out people.
 
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Vtx531

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Not recommended by whom? Even BFG customer service will give you lower pressures than the pressures on the door placard if you tell them you are "upsizing" from the stock tire size for your vehicles.

Actually, it is typically recommended by nearly every experienced offroader and offroad vehicle outfitter to run lower pressures than originally specified by the manufacturer when going to larger than stock tires and has been for 60 years if not longer.*

Then there is this:

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





A 285/75R16 is sometimes referred to as a "metric 33."

Although the "optimum" pressure may vary depending upon the particular tire, actual weight of the jeep, etc., is it generally recommended to run 26 psi with that size tire on a TJ. If your jeep is fully loaded, equipped with heavy body armor, etc., you might experiment with 28 psi.

It will take a bit of experimentation to find the "optimum" pressure for your tires and your jeep.



__________________________________
* I count nearly 60 years from the time that Dick Cepek, one of the first to bring flotation tires to the offroading market, taught that lesson to me as a teenager while accompanying my father to buy a set of tires from Mr. Cepek when he was still operating out of his one car garage in South Gate California.
LT Flotation tires are different animal than LT metric and in fact do have inflation tables that go as low as 25psi.
 

Mr. Bills

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You really need to learn how to use the TRA Load Inflation Tables before you start spouting nonsense. If the weight of your vehicle isn't listed in the chart for your tire size and you can't or won't extrapolate, then you need to use the Load Inflation Index for your tires, the weight of your vehicles on each tire, and do the math yourself.




If you want to bounce down the road in your TJ on 33's at 35 psi that is your choice, but it isn't a choice that anyone who knows what they are doing would make.
 
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Vtx531

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You really need to learn how to use the TRA Load Inflation Tables before you start spouting nonsense. If the weight of your vehicle isn't listed in the chart for your tire size and you can't or won't extrapolate, then you need to use the Load Inflation Index for your tires, the weight of your vehicles on each tire, and do the math yourself.




If you want to bounce down the road in your TJ on 33's at 35 psi that is your choice, but it isn't a choice that anyone who knows what they are doing would make.
That link backs up everything I said.

You can’t extrapolate off the chart. Load/pressure is not a linear relationship.

Personally, If I had large LT metric tires, I would run 28 psi - what Jeep recommends for 30-9.50-15.