There are four things standing between you and the pavement when you drive—your tires. Keeping them in good shape is key to staying safe on the road. Whether you’re gearing up for a long drive or just your daily commute, knowing how to check your tire pressure is a small step that can make a big difference.
That’s because the right tire pressure can have some far-reaching impacts:
- A smoother ride and better handling
- Better fuel efficiency
- Improved stopping distance
- A longer lifespan for your tires
What’s the right pressure?
If you drive a passenger car, your tire pressure is likely between 32 to 35 pounds per square inch (psi). SUVs and trucks require a higher psi. Here’s how to find the exact number:
- Open your driver’s side door.
- Look along the doorjamb for a sticker. It should display the pressure (including whether you need specific pressures for front and rear tires and your spare).
- You can also find the recommended pressure in your owner’s manual.
- Importantly, do not go by the number that is on the sidewall of your tires. That is the maximum pressure allowed.
Dangers of Overinflating or Underinflating Tires
You want the right amount of pressure in your tires, not too much and not too little.
- Overinflating causes the center of the tire’s tread to wear faster. It also decreases traction and your tire’s ability to absorb impacts.
- Underinflating causes the outer edges to wear faster. Your car may pull or drift to the side.
- Both overinflation and underinflation cause uneven wear, which reduces your tires’ lifespan. At the very least, it will require you to purchase a new set sooner than normal; at the worst, it could cause a
Start with the Right Tools
Now that you know the basics about tire pressure, you’ll want to gather the right tools. You need a tire pressure gauge to start. While you could use one built into an air machine at a gas station, those aren’t always the most accurate. It’s always good to have your own, which you can use at home and anywhere. You can purchase a gauge at an auto supply or hardware store. You will likely have a choice of three kinds:
- Stick gauge: Usually the most inexpensive option, this type of gauge resembles a pen. It has a small bar that pushes out to show the reading.
- Dial gauge: This type of gauge has a round dial that looks like a clock face or compass. The needle will stop at the number to show the reading.
- Digital gauge: This gauge has an LCD display showing the pressure in numbers. However, it needs batteries to operate and when they run out, you will need to replace them.
Optional but handy:
You can buy a portable air compressor to allow you to fill your tires anywhere and not just at a gas station’s air compressor kiosk. These vary from manual hand-operated or foot pumps to those you can plug into your car’s battery or a 12V power port. You will pay more for one with a built-in gauge, which can be helpful. If you are considering a purchase, look for one where you can put in the proper pressure and the unit will shut off when it reaches that number.
How to Check Pressure
You should check your tires’ pressure monthly or whenever there are changes in weather that could affect them.
- Start with a “cold” tire which is when a vehicle has been parked for 3 hours or more, or one that has been driven less than a mile at moderate speed. Tires heat up when they’re driven and that will increase the air pressure, and you won’t get an accurate reading.
- Remove the screw-off cap on your tire’s air valve. Put it someplace safe where you will not lose it.
- Place your tire gauge over the valve and push it into the stem. If you hear air escaping, continue to press it in until that stops.
- Check the reading on your tire gauge. Note that some gauges need to be in the tire’s valve for the reading; others may be removed.
- If the reading matches the recommended pressure, screw the cap back on. If not, take the next steps to add air or take it out.
- Repeat for each tire.
- If you can access your spare, do it for that one as well. It will be helpful to have a spare ready to go should you need to change a tire.
How to Add Air
You can find air compressors at most gas stations, and they are often free or a minimal charge.
- Park so the tire in need is closest to the machine so the cord will reach.
- Read the directions on the compressor before paying (if there is a cost). Once you pay, you should hear the machine turn on.
- Remove the screw-on cap on the tire valve. Put it somewhere safe.
- Press the hose nozzle on the stem of the valve. You should see the tire inflating and the numbers on the air machine going up.
- If you hear a hissing noise, you’re letting air out. Push the nozzle in to attach it properly.
- Check the pressure with your gauge.
- Repeat until you have the right number. Replace the cap.
If you had to drive a few miles to get to a gas station with air, your tires will be hotter than normal. Remember your base “cold tire” reading and calculate the difference between that and the ideal pressure. Add that amount. (For example, your tires needed to be 33 psi but were only at 31 psi in your driveway, you will want to add 2 psi.) Then, check again later after the tires have been sitting for 3 hours to make sure it’s the right amount.
How to Remove Air
You don’t need an air machine to let air out. You just need a flathead screwdriver.
- Take the cap off the valve.
- Press the end of the screwdriver into the center of the valve stem.
- Hold it for a few seconds. Listen for air escaping.
- Check the pressure and repeat as necessary.
Pressure Changes by Season
As the weather changes, you will notice corresponding changes in your tire pressure. That’s because air expands as it gets hotter, which raises the pressure. It contracts as it gets colder, which lowers it. In cold weather, tire pressure can decrease about 1 psi for every 10-degree drop in temperature. That’s why it’s important to check your tire pressure when the weather changes, in extreme heat and cold, and adjust as needed.
Note that your car’s tire pressure light activates when there’s a temperature change as well as a small leak. The light goes on when the pressure is about 25% below the recommended level.
A Word About Air vs. Nitrogen
When it comes to keeping your tires inflated, you have a choice: air or nitrogen. If you have nitrogen in your tires, you will need to revisit a nitrogen provider to fill your tires. You will not be able to fill them at air kiosks at a gas station.
Keeping the right tire pressure will help extend the life of your tires. Keeping your vehicle well maintained will help extend its life. Finally, protect it with the right insurance coverage. This will give you peace of mind for your journeys ahead. Safe travels.
This article is furnished by California Casualty, providing auto and home insurance to educators, law enforcement officers, firefighters, and nurses. Get a quote at 1.866.704.8614 or www.calcas.com.
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