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Double Nickels

Tire Pressure

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This may have been discussed on another thread.

 

Does everyone use the door sticker?  OEM tire sidewall says 51 PSI.  That's the maximum cold PSI.  Door sticker recommends cold PSI as 41 & 44.  After driving around all day, with hot PSI, I topped off at 51, and left 1 tire alone.  The next morning, I checked cold PSI, and it was as I guessed, below 51.  Then I checked again later in the day, where hot PSI was about 51.  Then I stopped off the last tire at 51 while hot.  Cold PSI in the morning is about 46.  I am okay with that.  

 

 

 

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The max pressure on the sidewall is what the tire manufacturer says  -  Don't go above this number or the tire will be so stiff and inflexible that when you hit a pothole you'll damage the tire . . . . probably break a belt

 

The door sticker is the vehicle manufacturer telling you that their number is safe, will give you decent gas mileage and a somewhat comfortable ride  -  Don't go below this number no matter what, because you could be compromising safety.  Underinflated tires heat up and too much heat destroys the tire carcass  -  You can't see it happening, but this is what causes most blowouts . . . . a tire that was overheated 2 or 3 times in the past finally comes apart when you least expect it

 

I use the door sticker number, plus 10 to 15% on all my vehicles

 

Don 

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If I run more than 41 psi in my rears, (Door Say's 44) in my 2015 LB XLT wagon I'll burn out the center treads In No time.

I run light with the third row seats out, 40 psi in the front and 41 rear year around with regular 5,000 mile rotations to get even tread wear...

 

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Thanks @Osco.  That's very helpful!

Edited by davidparker
spelling

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I am operating 51 PSI.  My tires do not show a "chicken stripe".  No discernable ride quality or handling difference.  Maybe 1 MPG difference on long road trips which see all highway miles.  

 

The door sticker is a recommended inflation PSI. This is the PSI which the manufacturer believes will give acceptable ride quality, carry the GVWR, allows for adequate traction, and provide acceptable mileage.  You can decrease the PSI for better traction and possibly better ride quality.  Max PSI on the tire is just that, the maximum.  At MAX COLD PSI, the tire will be at it's maximum lo9ad rating, usually gets a little better mileage (if you really need to increase 1/2 MPG to 1 MPG), offers a bumpy, harsh ride; and unless you are loaded to maximum load range,  less traction.  These are always cold PSI numbers.  Check your tires in the morning, before any driving.  This is when you will get the "cold PSI" reading, and the best time to make any adjustments.  Obviously, not everyone has an air compressor for this, so some adjustments may not be entirely precise.  

 

On trucks & Jeeps I've learned to decrease PSI for off road and inclement weather conditions.  Although I have yet to "feel" any need to decrease the Transit Connect PSI.  Even driving through storm conditions, the front wheel drive van maintained adequate traction.  Huge difference in traction, handling, and control on wet roads, when compared to a bigger, heavier, rear wheel drive truck.  On my truck, you can actually "feel" the difference in 10 or 20 PSI difference.   

 

I am not endorsing, or in any way suggesting, that anyone else inflate their tires to 51 PSI.  Everyone should do whatever they want to, or do whatever they feel is most advantageous to their driving condition.  But it could be interesting to read other replies.  

On 10/20/2019 at 1:26 PM, Osco said:

(Door Say's 44) in my 2015 LB XLT wagon I'll burn out the center treads In No time

 

On 10/20/2019 at 1:26 PM, Osco said:

with the third row seats out, 40 psi in the front and 41 rear

 

Very interesting.  I didn't think about decreasing the vehicle weight by removing seats.  Do the cargo vans have a door sticker with different PSI recommendations?

 

 

 

 

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8 hours ago, Fifty150 said:

I am operating 51 PSI.  My tires do not show a "chicken stripe". 

 

 . . . . and you shouldn't!  -  Any quality steel belted radial should be fine at the maximum pressure indicated on the sidewall and not show any unusual wear patterns.  My other 3 cars are all EV's and I run all their tires at or very near the maximum pressure on the sidewall and the tread on all of them wears perfectly flat from one side to the other

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Fifty150,

Mines the Long wheel base wagon, Max load rating is reduced to 1250 lbs due to the extra seats and all those windows, they require more metal support

so less cargo weight. The third row I took out I bet weighs 100 pounds.

 

To others running the door sticker pressures, 41, 44 I've tried with more than one brand of tire.

Door pressures:

Burned the rear center treads down really fast.

Handled ok but the back end was skittish when pushed in a corner ( I know Its a Mini van but It handles, I love chasing Mini Coopers down mountain switch backs)

Made more noise,

Slipped more on wet take offs,

Was a much harsher ride,

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I'm wondering how accurate the OEM TPMS system is.  It's good enough for what I need. But it's probably not a precision reading.

 

I used the tire inflator @ Costco, set to 51 PSI.

 

 

Here are my screenshots right after topping off the tires, and after 30 minutes of driving.  And in the morning, after cooling down overnight, the tires will be a little lower.

 

 

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The OEM TPMS system is pretty accurate. As far as "accurate" goes, that means within 2% margin of error. Based on your readings, you're in the ballpark of 2%.

 

Some things to keep in mind:

 

All tires have a maximum pressure on the sidewall. It is required by law, and for liability of the tire manufacturer. This means the tire should not exceed the maximum pressure when inflated cold (before driving).

 

Since the tire may fit many vehicles, it's up to the VEHICLE (not tire) manufacturer to decide what the inflation pressure should be, based on many factors. This cannot exceed the maximum pressure on the sidewall of the tire.

 

Assuming your are using compressed air, and not pure Nitrogen, Tire pressures will fluctuate with temperature, about 3 pounds for every 10 degrees of temperature.

 

Tires are rubber, and rubber is porous, meaning tires will generally lose about 2 pounds of pressure a month, naturally.

 

Tire pressure and vehicle maintenance dictates tire pressures should be checked on ANY vehicle at least once a month, and adjusted to the vehicle manufacturers specification with the tires cold.

 

So your numbers are accurate. I see a minimum of 49.8psi and a maximum of 52.9psi, well within the 2% margin, adjusted for driving time / temperature.

 

At the end of the day, set your tire pressures to 44psi cold front, 48psi cold rear, and barring any abnormal leaks, you can sleep like a baby for 30 days.

 

 

 

 

Edited by zalienz

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