What tire pressure to run?

[The_LeRoys]

I've always run my tire pressure at the max that is on the sidewalls of the tire, especially when towing. My tires are Michelin LTX MS2 tires, and have a max of 80psi. Should I be running them at the max? Or run them at the sticker on the side of the vehicle door? What difference will it make?

[rhagfo]

The LeRoys wrote:
So my tires are Michelin LTX MS2 tires, size 245/75/R16.

The door sticker calls for 245/75/R16E tires. To be run at 60psi Front and 80psi rear.

Here are my weights from last year. I need to get current ones.
1) Loaded Van with no Trailer
Front Axle - 3,220 lbs (73% of GAWR): 1610lbs / tire
Rear Axle - 3,920 lbs (64% of GAWR): 1960lbs / tire


2) Loaded Van with loaded trailer
Front Axle - 3,380 lbs (77% of GAWR): 1690lbs / tire
Rear Axle - 4,740 lbs (78% of GAWR): 2370lbs / tire

Well the 245/75-16E are rated at 3,042# each, so to carry a bit further.

Unloaded
Front 1,610# = 52 percent of tire capacity
Rear 1,960# = 64 percent of tire capacity

Loaded
Front 1,690# = 56 percent of tire capacity
Rear 2,370# = 78 percent of tire capacity

Keep in mind you are only running 78 percent of the axle rating, the 80 psi is for the axles GAWR likely 6,084#.

I don't have a current link to an inflation table, but at that load 65 psi to 70 psi would give you the best contact patch from your tire.
.

[1ofmany]

rhagfo wrote:

1ofmany wrote:
OK, let's get out the slide rule and a couple of calculators...and adjust for sea level and ambient temperature...just kidding, run at max pressure and you will not run the very real risk of running on underinflated tires.

:S

No now most likley unless fully loaded you are running your tires OVER-INFLATED, which in order of importance will cause
LESS traction for turning and braking!
LESS tire life as they will wear in the center.
The feeling of riding on rocks!

Well, there you go....

[The_LeRoys]

So my tires are Michelin LTX MS2 tires, size 245/75/R16.

The door sticker calls for 245/75/R16E tires. To be run at 60psi Front and 80psi rear.

Here are my weights from last year. I need to get current ones.
1) Loaded Van with no Trailer
Front Axle - 3,220 lbs (73% of GAWR): 1610lbs / tire
Rear Axle - 3,920 lbs (64% of GAWR): 1960lbs / tire


2) Loaded Van with loaded trailer
Front Axle - 3,380 lbs (77% of GAWR): 1690lbs / tire
Rear Axle - 4,740 lbs (78% of GAWR): 2370lbs / tire

[msgtord]

My truck came with 245/75/17 tires that the door sticker says 75 frt/ 80 rear. I now have 285/70/17 Nitto's. An email from Nitto states I should now run 61 psi front and 65 psi rear when unloaded. I'll bump up the pressure a bit depending on the load.

[time2roll]

Assuming you have OEM size tires and are within your ratings the door sticker is fine. Although I prefer to add 5 to 10 over that amount not to exceed the sidewall max.

[rhagfo]

1ofmany wrote:
OK, let's get out the slide rule and a couple of calculators...and adjust for sea level and ambient temperature...just kidding, run at max pressure and you will not run the very real risk of running on underinflated tires.

:S

No now most likley unless fully loaded you are running your tires OVER-INFLATED, which in order of importance will cause
LESS traction for turning and braking!
LESS tire life as they will wear in the center.
The feeling of riding on rocks!

[BB_TX]

I run my Superduty Michelin LTX MS2 tires at door sticker pressures, 80 rear, 65 front. If I have no plans to tow any time soon, I sometimes lower my rears to 65 also since there is little weight on them.

[CapriRacer]

Dick_B wrote:
When such questions arise I often wonder how does the door sticker know what tires are on the vehicle if the OEM tires have been replaced by another make/model tire?

It knows because the tire size is listed there as well, and the load carrying capacity for a given size is standardized by the tire standardizing organizations, such as the Tire and Rim Association. Every tire manufacturer agrees to those standards, so it doesn't matter who makes the tire or where it is made.

But change tire size and the pressure value has to be recalculated.

Oh, and the letters on a tire are part of the *size*. An LT tire is different than a P type tire, and even though the numbers may be the same, the pressures would be different (by 15 psi)

[Dick_B]

When such questions arise I often wonder how does the door sticker know what tires are on the vehicle if the OEM tires have been replaced by another make/model tire?

[mowermech]

rtz549 wrote:
If the door sticker says 35 psi; you'd likely damage the sidewalls of those 80 psi tires. Just run them at 80 and have peace of mind knowing the pressure is not too low and they are not under inflated.

If that is true, Please explain why the Jeep Wrangler Rubicon came from the factory with LR E tires, with a recommended air pressure of 33 PSI, and for off-road use the pressure could be reduced to 12 PSI.
My '06 Rubicon never had a sidewall failure, even at freeway speeds on a hot day!
Putting 80 PSI in the tires on a Jeep Wrangler would be incredibly stupid!

[mkirsch]

Since this is an E350 van, it certainly was designed for LT-E rated tires from the factory, so the door sticker numbers are appropriate.

Door sticker says 55PSI front, 80PSI rear for LT-E rated tires.

So asking/arguing about it is a complete waste of time and breath, at least on the rear: 80PSI is max sidewall pressure, and the recommended pressure on the door sticker. Somehow you guys will still figure out a way to argue about which is right and which is wrong, though.

The PSI ratings are based on the maximum load the truck/van is designed to carry on each axle. These are in turn based off the tire manufacturer's inflation tables, which are pretty much the same from manufacturer to manufacturer when you are comparing apples to apples: That is, a 245/75R16 LT-E to another manufacturer's 245/75R16 LT-E, for example.

[JIMNLIN]

Kind of a how heavy is my rock question with no specifics.

Load E tires may be a LT225/75-16 at 2680 lbs capacity or a LT305/75-16 tire at 3500-3700 lbs capacity. How much weight the truck/van is carrying when loaded vs when not carrying a load means different pressures. And yes it can means a lot of difference.
Some folks just pump them to the max and replace them in 30k-40k miles.

I air my tires on my trucks to the pressure for the load. I usually run load E truck tires for 70k-80k miles and always change tires just before the wear bars show.
However I know all my vehicles loaded and unloaded axle weights and I have my own compressor so airing up or down is no problem.

Without any specifics on your tire sizes and axle loads just pump them to the max and hope for the best long term service.

[ronharmless]

I run mine at 60 psi, that's enough to carry 2800 lbs per tire.

[1ofmany]

OK, let's get out the slide rule and a couple of calculators...and adjust for sea level and ambient temperature...just kidding, run at max pressure and you will not run the very real risk of running on underinflated tires.