Under Pressure – The Ins and Outs of Tire Pressure

Under Pressure – The Ins and Outs of Tire Pressure

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Ohhhhhh snap, Martha.  The tire pressure light just flashed in your car.  What do you do?  

First off, don’t panic.  

Second off, let’s check your tire pressure.  It’s super simple and anyone can do it with a tire pressure gauge.  

Now I’m going to tell you how to save a little cash and A LOT of time!

Hold up, rewind!

I’m getting ahead of myself here.

You should know why having the wrong tire pressure is bad, first and foremost.

Underinflation is the most common cause of tire failures.  Whoomp whoomp whoommmp.

Underinflation can lead to:

  • Uneven wear
  • Tire cracking
  • Tread separation
  • Decreased gas mileage
  • Risk of a blowout, which can lead down the ugly path of injuries.  Ain’t nobody got time for that!

Fun fact: a tire can lose up to half of its air pressure and still not appear to be flat!

Where to find the appropriate PSI for your tires

In your driver’s side door jamb, my good sir.  The owner’s manual works, too, but the sticker is WAY easier to find/use.

Here’s a picture of my car’s Tire and Loading Information sticker inside the driver’s door jamb.

*Take note if your front is not the same PSI as your rear*

As you can see, the PSI ratings are relatively easy to find.

What do I use?

I prefer this little guy: http://amzn.to/2t8Kk0L

It’s cute (the fact that it’s shaped like a tire tickles my funny bone), it’s relatively inexpensive, has great reviews (4.7/5 stars), *and* it comes with a tire tread depth gauge –more on tread depth in a later post.

Another bonus: The gauge is ‘enclosed’ which makes the measurement more accurate than your typical ‘stick’ gauge.

Notes before checking your tire pressure

Before you go out to put air in your tires, you have to know a couple of background key points:

A) The PSI ratings of your tires according to your car specs.  (PSI = Pounds per square inch of air within the tire)


**Always use your car’s specs for tire pressure, NOT what’s on the tire for max pressure**


B) Are your tires ‘hot’?  i.e. Have you driven more than a mile in the last 20 minutes or so?

Write the PSI down before heading to the gas station.  The tires will warm up from your starting point to the destination point and you have to take into account that difference.  Add the appropriate air pressure once you’re at the pump.

Let’s throw in an example:

  • Jane notices her back driver’s side tire is looking low.
  • She grabs her handy-dandy tire pressure gauge (http://amzn.to/2t8Kk0L) and records the pressure — let’s say it’s 35 PSI — before going to the gas station.
  • Once at the gas station, Jane checks the pressure again.  Now it reads 38 PSI!  Look at that, just from driving to the gas station the PSI went up 3 units!
  • Jane looks at the specs for her PSI on the sticker in the door jam and her tires call for 45 PSI.

Here’s where writing down the ‘cold’ pressure comes into play.

Should Jane add a 10 PSI or 7 PSI?

If you answered 10 PSI, you are correct!!

  • After Jane adds the air, she should check with the gauge (try not to use the gauges at the gas station, as they can be very unreliable) to make sure she’s at the appropriate PSI — in this case, 48 PSI is appropriate since her tires are ‘hot’.
  • Jane is really ambitious and wants to double check the PSI when the tires have ‘cooled off’.  The gauge reads 45 PSI.  Booyah!  You go, Jane!

PS – If there is too much air, press on the stem in the middle of the valve to release the air.  Rinse and repeat until you’re at the appropriate PSI.

Now, what you all came here for:

How to use the tire pressure gauge

For those of you who like to watch it be done, here ya go:



Step 1

Remove the valve stem cap — it should be a twisty-off.

Remember: lefty-loosey, righty-tighty.


Do not lose the cap!!  Put it in your pocket or somewhere safe.

Step 2

Firmly press the tip of the gauge to the tip of the valve stem for 2-3 seconds.  You’ll hear the air escape the tire and simultaneously you’ll see the gauge read the PSI.

Step 3

Get to an air-filling station.  You can usually find free air at most gas stations.  Some mechanic shops may even have air pressure available for the public.  How neat is that?

Step 4

Add or release air to reach the recommended air pressure.  I can’t emphasize this enough – use your door jamb sticker or owner’s manual for the appropriate PSI!  Use the same procedure for filling the air as checking the PSI with your gauge.  Press the air stem firmly into your valve stem.  You’ll hear a hissssss as the tire is inflating. Recheck the PSI with your gauge until you’re at the correct level.

Step 5

Replace valve stem cap.

Oh hell, where did you put it again?  That’s right!!!  In your pocket.  Time to do the ‘pocket check dance’ and look like a crazy person.

Step 6

Repeat steps 1-5 for each tire.  It’s a good idea to check the spare tire, too, in case you ever need to use it.


There, now you have done your very first tire check.  All by yourself!!  I am so proud of you!  Seriously, pat yourself on the back.

And remember, you just saved a little bit of cash and A LOT of time not going to the mechanics (time is money!).  Throw a couple dollars in your “Saving for Something Fun” account.

Ohhhhh yeahhhhh — time to do a little happy dance (and still look like a crazy person).

PS –

I’ll tell you a funny story about a flat spare one day.  It involves 3 teenagers, an exhaust pipe, a flat spare, a casino, and no license.

64 thoughts on “Under Pressure – The Ins and Outs of Tire Pressure

  1. I have totally checked my air pressure tons of times and never new the cold vs. hot air pressure difference! Thanks for the knowledge!

  2. This is very helpful. I know nothing about cars and I’ve panicked when that air pressure light comes on. Now maybe I don’t have to wait for my husband to fix it!

    1. I’m glad to hear this is useful info for you! *Virtual high five* Let me know how it goes when you try it out for yourself. 🙂

    1. Thanks, Jacqueline! Car stuff can be kind of ‘stuffy’, so I’m trying to keep it light and entertaining! Glad you like it! 🙂

  3. First off, I love the way you write. So easy to get through the info! My tire pressure is always off… maybe a slow leak? I like it when I put winter tires on because those rims don’t have the detection thing and that little indicator light is always on so that’s my excuse. I should probably brighten up… ?

    1. Thank you, Rachel! I’m striving for simplicity. 🙂

      It’s possible you have a slow leak? Different outside temperatures will affect your tire pressure, so I’d suggest taking the P (pressure) before leaving the house for the day, and then again after your car has sat for a while. Then you’ll see if there’s any loss of air. If there is, definitely take it into a professional — they can guide you in the right direction, for sure.

  4. Great tips! Having taught my three kids to drive, I think your site would be great to add to a homeschool drivers ed course.

  5. This is great info. I didn’t know how to check pressure at all. I should have learned this before now haha. Thanks!

  6. This is great information for people! No one used to even notice until the tire went flat! Now, our cars tell us what is wrong, but not how to fix it. Thanks!

  7. I have been in a situation when I didn’t know how to check my pressure or add air to my tire. After realizing men don’t step up like they used to I decided to learn myself. Now I can do it myself! Girl Power!

  8. This is helpful! I knew the pressure changes when the weather gets colder. I especially liked the “oh hell, where’s that valve cap!” 😂

  9. Thank you for the tips! I am not sure what I would do without my husband. I could definitely use more tips, and tutorials like this. I would definitely be searching online for help if I wasn’t married to a mechanic! You broke everything down very well. I know nothing about cars, but I bet I could do this after reading your tips!

    1. Aww thank you so much for the kind words, Michelle!! It does help having a mechanic in the house, for sure! 🙂

  10. This is so wonderful! Wish I had had this when I was 18 and had my first car in college. Would have saved me a ton of stress!

  11. I wish I this blog a log time ago! I am subscribing to it right now! Facebook, twitter, google+ and whatever else outlet you have! this is great!

    1. Thank you, Amanda!!! I’m just starting out so I don’t have a bunch of stuff on social media yet, but it’s definitely coming in the near future! Glad to hear you subscribed! You’ll even get a little freebie to keep in your glove box. 🙂

    1. Isn’t that just about the cutest thing in the world? We should totally learn this basic stuff in Driver’s Ed!

  12. Learned something new…taking the pressure both when the tires are cold and hot. Hmmm. Makes sense, just never thought about it. Thanks.

  13. My husband always tells me to check my tire pressure. Then he ends up checking for me 😂 This is a great reminder though!

  14. This cracked me up! Mine just went on a few days ago, then went off on its own….Thanks for the tutorial though, I honestly had no clue about the hot/cold thing…I’m going to tell my hubby (he better be impressed by my knowledge) 🙂

    1. You’re the ‘expert’ now, right???? Ps – I’d double check your tires just to be on the safe side. 🙂

  15. Thanks for the good tips! I am not good with this car stuff, but might be able to manage with pointers like this!

    1. Thanks, Karawellmantraining! I’ll be posting a couple times a month, so keep an eye out for new tips! If you’d like to subscribe, I’ll be sending out a Newsletter every couple weeks, too. I don’t want to jam up anyone’s email. 🙂

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