How To Check Your Car's Tire Pressure

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(114335) electric tire pump

Since we're supposed to check our car's tire pressure every 3-4 weeks, you'd think most people would know how to do it. Then why would I see so many cars on the road (I’m an X-mechanic, so have an eye for this) with less than ideal tire pressure? Is it because we're lazy, forgetful or just aren't sure how to do it? Well, in this article I’ll teach you how to check your car’s tire pressure as well as some commonly related problems.

There are a number of reasons why one would want to maintain the car's tire pressure at an optimum. The challenge of knowing what the pressure should be is already calculated by the car manufacture. This number in PSI or Pounds per Square Inch is a unit of measurement for pressure.  When designating a correct PSI for our car the engineers take into account the cars weight, tire dimensions and ride characteristic. This will produce the most balanced ride for a specific car. So for example, the tire pressure in a corolla will not be the same as a Camry or Impreza.  On a side note, the tire pressure for the front tires will not always be the same as the back but pressure for the left will always match the right.

Common tire conditions:Overinflation- If the tire pressure is over the recommended PSI the tire's contact patch on the tarmac or ground will be reduced, producing less traction. Most people will overinflate their tires if they do not use a tire gauge to check their tire pressure. This is because modern day car tires are meant to be slightly "saggy" at the bottom giving a false sense of under inflation; where as the top of the tire will remain square-ish looking. Many will fill the tire up until the bottom side resembles the (114495) tire inflationtop. This will most likely cause the tire to be overinflated. Always use a tire gauge when filling up air to prevent this. 

Underinflation- is very obvious. The bottom part of the tire is compressed significantly. In the unlikely event this goes unnoticed the tire may slip off the rim during highway speeds or cornering and cause an accident. If you have a flat tire completely deflated,  there will be no air to support the rim or car. If you start driving you will irreversibly damage the tire RIGHT AWAY and may also dent the rims. Do a visual inspection of your tires few days to make sure you don't have underinflated tires. 

Tires Will Always Leak Air Why? Because tires rubber compound is porous and will always leak air. Having said that you should not see more than 1 psi change in 4 weeks time. If you have to fill up air every week, you have a slow leak and should have it checked for nail, punctures etc. I’ll say this again, check your tire pressure with a tire gauge every 3-4 figure

The Money Factor If your tires are underinflated, they willcreate more friction; which causes premature wear (shortening the tire’s lifespan) and increased fuel consumption.

How To Check Your Tire Pressure

1) Purchase a tire pressure gauge (I have one in every car. They're $5-10US).  Metal ones are more durable and if you want one that's easier to read, go digital. Tire pressure gauges at the gas pump are not very accurate so I never trust them. pressure spec

2) Open the driver's door and you will find a label with black print specifying the front and rear PSI around 28-35. This reading will also be printed in the owner’s manual.

3) Make sure the tires are "cold" meaning you have NOT driven the car. If you've been driving for 20mins in stop and go traffic your tires are likely to have warmed up and checking the tire pressure then would be misleading.

4) Unscrew the black or green (Costco’s will be green- as they use helium which isn't affected by tire temperature) valve cap. The valve is the one inch black nipple protruding at a 45degree angle from the perimeter of the rim.

5) Take your tire pressure gauge and insert the opening onto the valve nipple. Make sure the gauge opening is aligned straight with the nipple or air will start leaking. Once inserted, read the meter. Your reading will be inaccurate if air leaks during this check. Compare the designated PSI with yours and release air if it's over, inflate if under.

Deflating An Overinflated Tire

The simple analogue pressure gauges have a small stub on the opposite side of the nipple insert. Use this stub and depress it onto the valve nipple and air will be released. If you have some fingernails, you could use those as well.

Inflating Tire At The Pump

1) Take the air hose, press button to turn on the pump or insert money to start. Pull or stretch out the hose to the first wheel and insert the tip of the hose into the valve nipple.

2) Put both hands on the hose, one holding the tip of the hose, the other on the lever. Push the tip of the hose STRAIGHT in to the valve/nipple. Create a good seal then squeeze the lever with the other hand for 1-2 seconds to just top up the tire pressure. For a very underinflated tire inflate for about 5 seconds and check with your own tire gauge.

3) Repeat for all your tires.

4) Remember to put your valve caps back on! They're there for a reason - to keep dust out which causes leaks.