Optimal Tire Pressure

[ShadowsPapa]

You inspired me to look deeper. Falken didnt have a tire pressure chart on their product page but it was in their warranty/maintenance section. Looks like my 255/75/17 M/T tires can go from 35-50psi, currently at 40 from the dealer and rated for a little over 2000lbs each at that point. Plenty for the JT. Cant wait to try them out in some mud/snow

https://www.falkentire.com/tires/care-safety-warranty

There ya go. They have to support and warrant their tires - they have to tell you what they will or won't handle, what pressures to run to keep the sidewalls from heating up, belts from separating, and more. No one knows their tires like the maker. They know how much tire will be on the road for a given vehicle weight and PSI.
If you choose to go under 35 and have any trouble or premature wear - it won't be on them.

Now for me to continue looking for better all-weather tires for my Overland - more nasty roads around here, several accidents.

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[jrf]

AND right from Falken's website:

"*Some plus size applications may require different air pressure(s) than what is listed on your vehicle’s placard or owner’s manual. In this case, please consult your tire dealer or Falken Tire for proper inflation pressure(s)."

So...yeah...don't follow the door sticker when you change your tires....

 

[RH 67]

Carli suspension is a top suspension company for HD Dodge and Ford trucks they are considered at the top for HD suspension and i have used their products for years. Here is a post about tire pressures from their site i have used their recommendations for over a decade and i pull a 15k toy hauler. https://carlisuspension.com/tires-and-wheels-how-do-they-affect-my-ride/

 

[Renegade]

Carli suspension is a top suspension company for HD Dodge and Ford trucks they are considered at the top for HD suspension and i have used their products for years. Here is a post about tire pressures from their site i have used their recommendations for over a decade and i pull a 15k toy hauler. https://carlisuspension.com/tires-and-wheels-how-do-they-affect-my-ride/

But...Jeeps are not 2500 series trucks. I read the article, and I don’t think it directly applies. I do not prefer the door jamb pressures in my Jeep, but I also feel there are just too many variables for a quick one-size fits all on a forum, when limited info exists from the OP on what tire he/she will be using, and exactly how it will be used.

 

[Factoid]

No one can tell you the optimum tire pressure for your particular tire and set up. Anyone who says they can is suspect. For those who are real perfectionists, they will chalk test all four and run different pressures front and rear based on weight distribution. It makes sense as a front winch will add weight up front resulting in the need for slightly higher pressure, while loaded storage boxes in the bed will do the same for the rear.

I’m not that precise, however, when I add different tires (even did this on my ‘64 Corvette with 315/45-18 steamrollers) I start with 35psi, chalk all four and then air up or down depending on the result. Your mileage may vary.

 

[Oscar Indy]

So is the 37psi accurate for the OEM tires on my Glad_Rubi with OEM 33's?

Not that I've seen. Chalk test shows 31 to be optimal from my experience.

 

[Seansmd]

Not that I've seen. Chalk test shows 31 to be optimal from my experience.

Is that you in an empty truck?, multiple passengers?, fully loaded for an adventure?, all of the above?

 

[Oscar Indy]

Is that you in an empty truck?, multiple passengers?, fully loaded for an adventure?, all of the above?

full tank, loaded for options.
The thing about tire pressure in high volume tires is that temp affects them more than a passenger car tire. 31 turns into nearly 35 at highway temps. in my truck, the flightiness came back real bad over 35 on the factory tires.

A chalk test takes 2min just do you own.

 

[RH 67]

But...Jeeps are not 2500 series trucks. I read the article, and I don’t think it directly applies. I do not prefer the door jamb pressures in my Jeep, but I also feel there are just too many variables for a quick one-size fits all on a forum, when limited info exists from the OP on what tire he/she will be using, and exactly how it will be used.

It`s a guideline but the math does not lie when applied to the Gladiator just change the numbers. The 37" tires on a SD are the same being mounted on a Gladiator think about it.

 

[PyrPatriot]

Here is what Falken had to say about my new tires after I provided them information on the OEM tires. Basically saying I cant use these? At 50psi these should have 3300lbs over the curb weight of the JT, and I dont plan on using these tires for anything but off roading or travel to in-laws in rural eastern KY mountains

“Looks like the new tire size is overloaded to start with. The OEM tire size has a load range of 112, compared to the 111/108 of the new tire size. The OEM tire supports 2469 lbs per tire, with the LT255/75R17 supporting 2405 @ max 50 PSI.

While the 64 lbs per tire doesn't seem much, we also have to account dynamic loads when driving (turning, braking, cargo, etc).

A larger tire size would be need for your vehicle for public driving to minimize overloading the tires.”

 

[Oscar Indy]

HAHAHAHAHAHHAHAHAHHA
Got to love liability answers. I have no idea why psi is so hard for people. Its common sense and logic.....

 

[PyrPatriot]

HAHAHAHAHAHHAHAHAHHA
Got to love liability answers. I have no idea why psi is so hard for people. Its common sense and logic.....

I know right? I sent them basically my thoughts above: that even at 40psi the Falkens have a load of 3000lbs+ over the curb weight of the vehicle and should in theory be fine, especially in a vehicle not loaded down (aside from driver, bed mat, and sand bags totaling 600lbs). Curb weight of 4800lbs, 600lbs of payload/occupants, 5400lbs total load on tires. Each tire at 40psi is rated for 2055lbs, so 8200lbs. That leaves 2800lbs of load left, at 40psi. I could increase it to 45psi for 2230lbs per tire to get 8900lbs load capacity and have 3500lbs of load left, with 5psi wiggle room for things like temperature, barometric pressure, increased payload, etc.

Even under their Extra Load tire specs, the Falken 108/111 at 40psi are 2,123/2,315lbs. That is at least 8500lbs, leaving 3700lbs of load on the tires.

Or do you mean I have no understanding of psi?

@ShadowsPapa what do you think?

 

[Oscar Indy]

I know right? I sent them basically my thoughts above: that even at 40psi the Falkens have a load of 3000lbs+ over the curb weight of the vehicle and should in theory be fine, especially in a vehicle not loaded down (aside from driver, bed mat, and sand bags totaling 600lbs). Curb weight of 4800lbs, 600lbs of payload/occupants, 5400lbs total load on tires. Each tire at 40psi is rated for 2055lbs, so 8200lbs. That leaves 2800lbs of load left, at 40psi. I could increase it to 45psi for 2230lbs per tire to get 8900lbs load capacity and have 3500lbs of load left, with 5psi wiggle room for things like temperature, barometric pressure, increased payload, etc.

Or do you mean I have no understanding of psi?

@ShadowsPapa what do you think?

Not you at all. whatever kid they hired to man the website contact. Sounds like they are reading from a script or dont understand tires at all.

 

[PyrPatriot]

Not you at all. whatever kid they hired to man the website contact. Sounds like they are reading from a script or dont understand tires at all.

The laughs continue. I dont think he understood that these are not going to be used while towing or hauling 1000lbs in the bed

“When calculating tire pressure, vehicle manufacturer’s take curb weight with a grain of salt. When they calculate a specific air pressure, they are doing so to account for normal/dynamic loads. Majority of the time, the vehicle will be moving with load distribution changing. Curb weight is a static measurement, where the vehicle is not moving with no load, which is not used when calculating a recommended air pressure.

Jeep states 36 PSI for their 245/75R17 tire, which supports 2469 lbs per tire. This provides Jeep with a pressure that can support various loads during driving, comfort, and their claims on payload/towing/MPG.

To get this same load capacity, the new tire size will need to be adjusted in order to match or exceed OEM. At the very minimum, 50 PSI is needed for the new size. However, even then, the tire will not match the 2469 lbs capacity as the OEM tire size.”

 

[Oscar Indy]

The laughs continue. I dont think he understood that these are not going to be used while towing or hauling 1000lbs in the bed

“When calculating tire pressure, vehicle manufacturer’s take curb weight with a grain of salt. When they calculate a specific air pressure, they are doing so to account for normal/dynamic loads. Majority of the time, the vehicle will be moving with load distribution changing. Curb weight is a static measurement, where the vehicle is not moving with no load, which is not used when calculating a recommended air pressure.

Jeep states 36 PSI for their 245/75R17 tire, which supports 2469 lbs per tire. This provides Jeep with a pressure that can support various loads during driving, comfort, and their claims on payload/towing/MPG.

To get this same load capacity, the new tire size will need to be adjusted in order to match or exceed OEM. At the very minimum, 50 PSI is needed for the new size. However, even then, the tire will not match the 2469 lbs capacity as the OEM tire size.”

oh well. Do the math or a chalk test is the best answer. Their answer is lacking.

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