# Questions about tire pressure



## joecaption (Nov 30, 2011)

Close enough.
Spare needs to be checked every time.
Remove it and flip it over.
What goods it going to do if it's flat?
It would take three gauges and figure out the average to get it exact, not worth the effort.
Over inflated will cause the center of the tread to wear, under will cause the outside to wear. What's the tires look like?
Even the outside temperature and whether the vehicle has been driven will effect tire pressure.


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## 123pugsy (Oct 6, 2012)

Too much air and the middle of your tire tread can wear out sooner.
Too little air and you run the risk of a blowout. Also the shoulders will wear prematurely.

Use the one that reads higher and go 5 lbs under the max. Harder tires get better mileage.

Check the spare at least once a year.
You don't want to check it the day you get a flat.


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## ukrkoz (Dec 31, 2010)

Make sure you measure pressure "cold" as in - before driving. Hot tire expands air inside and bumps reading.


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## Mort (Nov 26, 2008)

You're well within the margin of error. Just go with the one that is cheapest.


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## Skidude108 (Sep 17, 2014)

123pugsy said:


> Use the one that reads higher and go 5 lbs under the max. Harder tires get better mileage.


If you mean the max written on the side of the tire, then I do not agree. 
You want to go with what the vehicle manufacturer recommended, which is printed somewhere on the car. I have seen it inside the gas flap, on the driver's door jamb, and even on the sun visor. It usually lists a normal pressure, and a pressure for when the car is fully loaded. Just pick a gauge and set it to the recommended pressure and you will be close enough.


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## 123pugsy (Oct 6, 2012)

Skidude108 said:


> If you mean the max written on the side of the tire, then I do not agree.
> You want to go with what the vehicle manufacturer recommended, which is printed somewhere on the car. I have seen it inside the gas flap, on the driver's door jamb, and even on the sun visor. It usually lists a normal pressure, and a pressure for when the car is fully loaded. Just pick a gauge and set it to the recommended pressure and you will be close enough.


I will agree with you only if the the tires on the vehicle are the exact size as the tires that were on the car when it rolled off the assembly line.

For my 1976 pickup, I look at the side of the tire. The info is always there.


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## rusty baker (Feb 13, 2009)

123pugsy said:


> I will agree with you only if the the tires on the vehicle are the exact size as the tires that were on the car when it rolled off the assembly line.
> 
> For my 1976 pickup, I look at the side of the tire. The info is always there.


People who put over sized or under sized tires on a vehicle are compromising their safety anyway. They won't care about pressure.


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## ratherbefishin' (Jun 16, 2007)

Sorry, pugs, but you're wrong. The rating on the side of the tire only tells you about the strength of materials and construction of the particular tire, it has nothing to do with the vehicle on which it's mounted. Proper inflation is determined by vehicle weight and tire size.

If you have aftermarket wheels and tires that are different from the vehicle manufacturers specs, just check with any good tire shop for inflation specs. They have vehicle specific charts just for that purpose.

Example: I could put stock size, 8 ply, load D tires with a max rating of 65psi on my old F150....but I'd be a fool to run that truck with 60psi....:wink:


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## 123pugsy (Oct 6, 2012)

ratherbefishin' said:


> Sorry, pugs, but you're wrong.
> If you have aftermarket wheels and tires that are different from the vehicle manufacturers specs, just check with any good tire shop for inflation specs. They have vehicle specific charts just for that purpose.


No worries. I've been wrong before.

But, I must only be half wrong if the tire shops have charts specific for tires other than OEM sizes that show a different PSI than the door jamb sticker.


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## 123pugsy (Oct 6, 2012)

ratherbefishin' said:


> Example: I could put stock size, 8 ply, load D tires with a max rating of 65psi on my old F150....but I'd be a fool to run that truck with 60psi....:wink:



Thanks.

I'll have to study up on the different load ranges and applications.


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## funfool (Oct 5, 2012)

Size does not matter. :jester:

If I have exact same size and brand, model tires the car came with, then I agree with using what is on the sticker in the door jamb.

But If I have a set of donald duck tires, that have a max pressure of 40 psi.
And a set of Goofy tires that have a max pressure of 32, and they are all the same size the vehicle manufacturer suggest.

I am going to take in consideration what the tire manufacturer suggest as the max pressure for that tire. I am going to look at the weight of my car, at the load I am hauling.
If I am pretty heavy and always carry some tools and a emergency kit, groceries etc...
My tire pressure on the sidewall says 32 psi, I am going to try 28 psi and see how I like the ride.
I might lower it a bit to 26 if I want something smoother.

If the tires said max psi is 35, then I am going to go for 32 psi .... Point is, I am going to go by the tire, and totally ignore what the sticker on the car says.
The sticker is a guideline but has absolutely nothing to do with a different set of tires on the same car.


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## cjm94 (Sep 25, 2011)

Just remember never to set it less than 50% of the tire rating. That is the minimum dot approved psi setting...remember ford explorers. They tried to fix a rough ride by lowering the air psi too low.


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