Tires Losing Air Pressure

I have relatively new tires on my car. The last few months, they have been losing air pressure, requiring me to refill them once or twice per month. Two questions:

  1. Why might this be happening? How do I fix it?
  2. I bought a portable air compressor. I can make out two different PSI numbers on each tire. How do I tell which is the right one? I’d tell you what the tire says, but it’s really difficult to read (I need a magnifying glass).

Look on the drivers door jamb for a sticker that’s something like this.

That’s the correct tire pressure(s)

As far as losing air, have a shop dunk the tires in a tire water tank to locate any leaks.


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I don’t know what numbers you are referring to. The tire pressure number on the tire is the maximum psi the tire should be inflated to. The tire pressure you should use will be on the drivers door plaque . Some where around 30 to 33 psi .

And why are you not asking the place you bought the tires from about this ?

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You have a sticker on your car (often on the driver’s door jamb) that tells you the pressure to use.

Has it been getting colder? That will decrease you tires’ pressure. Do you check them consistently, first thing in the morning before you drive?


Thanks. I’ll look for that (I hope it’s still there and readable).

But do those numbers apply only to the original tires? I do not have the originals.

If they apply to any tire put on the car, then I’ve been overinflating them for the past few months. I don’t think over-inflating could cause them to lose air pressure, but maybe you all can correct me on that.

I was referring to the numbers on the tires, but only because elsewhere on the internet I read that the tires’ sidewalls should tell you how much to inflate the tire to. But you (and others in this thread).

I am asking here because it takes less time and physical effort than to drive all the way down to my auto-mechanic (3 blocks away) and because I want to learn.

That’s the pressures for any tire mounted on the vehicle.


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That applies to any brand of tire on the vehicle . Two questions:

What have you been inflating these tires to ?

How long have you been driving ?

@sundayDriver Put ( numbers on tire sidewall ) in Google and it will find you many articles that really explain the numbers on the tires.

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Thanks for your reply.

I meant to put in the top post that weather is not an issue (that was why I brought up “past several months”, but I didn’t finish the thought).

I do not check them consistently, but the dashboard info center tells me when tire pressure is low. It seems pretty accurate.

Thanks. Is that because they are required to meet some standard? What I mean is, is there a chance I bought Cheapo Tire brand and the correct PSI is different

I’ve been inflating them to about 35-40 PSI.

Been driving for a long time. But never had tires that lost air pressure, so I literally never put a moment’s thought into this basic subject. The mechanics check air pressure during oil changes and it lasts to the next oil change.

Tire quality doesn’t change the recommended tire pressure specified by the vehicle manufacturer.


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What–exactly–is the brand of your tires?
The brand of tire is unlikely to affect how they maintain pressure, but… just for the record… what brand and model are they?

Also, I have to reiterate that the correct pressure for your tires is listed on a very durable placard that is affixed to the driver’s door jamb. Do NOT inflate the tires to the maximum pressure that is listed on the sidewall of the tire.

All of that being said, if your tires keep losing pressure, the problem probably lies in either the rims (the integrity of the seal can deteriorate over time with certain wheel rims…), or the tire valves. The tires themselves are unlikely to be the problem.


Very good advice on the tire pressure, look at the sticker on the door, if a tire fits your car it has to meet basic standards which includes air pressure.

Tell us about your car, make model year etc. My daughters 2012 RAV4 had one tire leaking, it was the rim rusting around the tire valves, I noticed a lot of older RAV4’s with the same rust. No way to repair it, so she now has some snazzy new rims and no more leaks.

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Did you change the tire size? If not, then the label still applies.

Note that the pressure molded on the tire says “maximum”, not “recommended”.

As for the supposed leak, assuming this isn’t the pressure going down with lower temperatures as would be expected, you can spray the tire with soapy water, especially around the bead area and the valve stem, and look for bubbles.

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2013 Chevy Impala.

Did not change the tire size.

I’m going to do that (spray the tire). TY

Depending on where you live, a loss of 5 pounds over the last month or two could be normal.

Here in AZ, we had high temps of over 100 degrees 2 months ago, and last week were in the 60’s. My wife’s 2012 Malibu lost about 5 psi per tire due to temp swing. My trucks at work have lost a little more than that due to their larger size.

I had a leaky tire, took it off, put it in the tub (I’m single.), found no leak. Took it to the llantero, who had a deeper tub, found the leaky valve. Had I just sprayed the valve with soapy water I could have figured it out myself. I lack tire tools, so I’d still have to go to the llantero. He charged $2.

That’s the same size. You go with a wider tire (aka larger footprint) then the tire pressure will be lower.

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