How Cold Weather Affects Tire Pressure
From corrosive road salt to slick roads, winter creates many challenges for drivers. Another one to add to the list: Tire pressure dips caused by lower temperatures.
Making sure your tires are properly inflated is an important part of getting the best performance out of your vehicle – especially during the winter months. After all, your tires represent the only point of contact between your vehicle and the road ahead.
Related: Whoa: Here’s What Road Salt Does to Your Car
Here’s everything you need to know about keeping your tires aired up.
WHY IS TIRE PRESSURE IMPORTANT?
Your tires require a certain amount of air pressure, measured in pounds per square inch (psi), to work properly. Too little (or too much) air can lead to poor vehicle handling, irregular tire wear and the potential for a flat.
HOW DO I MEASURE TIRE PRESSURE?
There are a few ways to tell if you need to air up your tires. If your vehicle was made after 2007, then it’s equipped with a Tire Pressure Monitoring System (TPMS). These systems will display a warning light on your dashboard if a tire has dropped below the recommended pressure. Hint: the symbol, which was designed to look like the cross-section of a tire, is similar to an exclamation point between two parentheses – (!).
If your vehicle isn’t equipped with TPMS, you can always check your tire pressure using a gauge. To use the tire pressure gauge, remove the plastic cap on your tire’s valve stem. Then, push the gauge onto the stem to get a pressure reading. If you don’t have a tire pressure gauge, you can pick one up at most gas stations or any auto parts store.
DOES TIRE PRESSURE DROP IN COLDER WEATHER?
If it seems your tire pressure warning light is going off more during the winter, it’s probably not your imagination. That’s because air contracts when it’s cold, causing tire pressure to drop between one and two psi for every 10-degree decrease in temperature. This means that your tires could be 5 to 10 psi lower than required on a 24-degree day than they are on a 74-degree day.
Related: 8 Things Your Car Needs in Winter
WHAT PSI SHOULD I INFLATE MY TIRES TO?
When it comes to inflating your tires, one mistake drivers sometimes make is to inflate their tires to the psi rating printed on the tire sidewall. But that reading is the tire’s maximum inflation pressure – which is often much higher than the inflation pressure recommended for your vehicle.
To get your vehicle’s recommended psi rating, check the sticker located in the door jamb of your driver’s side door. The recommended tire pressure should also be printed in your owner’s manual.
HOW LONG CAN YOU DRIVE WITH LOW PRESSURE?
When your tire pressure is low, you should inflate them to the recommended pressure as soon as possible. Underinflated tires wear more quickly and unevenly. This makes them more susceptible to damage and wear and tear. Both handling and braking are compromised when there’s not enough air in the tires. And if that’s not enough, underinflated tires are also a drag on your fuel economy.
WHERE CAN I GET AIR?
If you find out that your tires need air, you can either inflate them with your own portable air compressor or use an air compressor at a gas station. For a few dollars, it’s worth investing in your own pressure gauge. The ones at gas stations are convenient, but since they’re used often and exposed to the elements, they’re more likely to be inaccurate.
Many gas stations have free air and are automatic – you just set the intended psi. Take the time to carefully read the instructions if it’s your first time or ask the gas station attendant for help. It may not be the most fun part of owning a car, but it really is important.
Related: How To Keep Your Car Running for 200,000+ Miles
WHEN IS THE BEST TIME TO CHECK TIRE PRESSURE?
To get the most accurate reading, you should check your tires after your vehicle has been sitting for a few hours, and before you start driving. This is called “cold” pressure, because it’s the pressure reading before your tires (and the air inside them) have a chance to warm up from driving.
You should also make a habit of checking your tire pressure once a month. While you can rely on your vehicle’s TPMS system, a warning light usually only goes off once the tire pressure reaches a certain threshold – meaning your tires could be underinflated well before the warning light comes on.
SHOULD I OVERINFLATE MY TIRES IF I KNOW IT’S GETTING COLDER?
Just because the temperature is dropping doesn’t mean it’s a good idea to overinflate your tires. Your vehicle was engineered to perform best with the tires inflated to the manufacturers recommended pressure. Stick to those numbers, and your tires will perform at their best.
If you think your tires aren’t up to the job of winter driving, you might want to consider swapping them out. Read more in our ultimate guide to snow tires.
WHY DOES MY WARNING LIGHT GO OUT AFTER I START DRIVING?
If your tire pressure is right on the threshold of setting off your TPMS warning, you may find that the TPMS light goes off after you start driving. That’s because driving generates heat in your tires, and heat causes air to expand – raising your tire pressure.
But even if your light goes off after driving, your tires are still underinflated. So, air them up as soon as you can.
ARE THERE OTHER REASONS WHY TIRE PRESSURE IS LOW?
Temperatures aren’t the only factor that can affect tire pressure. If you inflate your tires to the proper psi but they’re low the next day, chances are there’s more than cold weather to blame. Your tires are likely leaking air.
A slow leak could be caused by a small puncture in your tire, or a bad seal between the tire and wheel. Either way, your best bet is to take your car to an automotive service center to get it inspected by a professional.
WHAT SHOULD I DO IF MY TIRE IS FLAT?
If your tire is completely flat, then you have a few options. If your vehicle is equipped with a spare tire and you’re comfortable with the challenge, you can save some time by changing it yourself. Watch how to change a tire in this guide from Popular Mechanics.
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