How to check tire pressure

Tires have been known to lose up to 1psi (pounds per square inch) every month, so check all tires, including your spare, once a month (or before a long trip).

Low pressure can lead to tire damage. See the inflation difference:

It’s easy. Here’s how:

1. Purchase a trusted tire pressure gauge.

2. Check your tires “cold”—before you’ve driven or at least three hours after you’ve driven.

3. Insert tire pressure gauge into the valve stem on your tire. (If you are using a digital tire gauge like the one pictured, the gauge should begin reading the air pressure immediately. Refer to your air pressure gauge owner's manual for correct usage instructions. If using a pencil-style tire gauge, the gauge will pop out and show a measured number. When you hear a hissing sound, that’s air escaping the tire. The escaping air shouldn’t affect pressure substantially, unless you hold down the air pressure gauge too long.)

4. Compare the measured psi to the psi found on the sticker inside the driver’s door of your vehicle or in the owner’s manual. DO NOT compare to the psi on your tire’s sidewall.

5. If your psi is above the number, let air out until it matches. If below, add air (or have a Michelin retailer help you) until it reaches the proper number.

Nitrogen versus compressed air

Most tires are filled with compressed air. But some tire retailers have started to put nitrogen into their customers’ tires. (Nitrogen is simply dry air with the oxygen removed. Air contains nearly 79% nitrogen already.) Because nitrogen replaces oxygen, less air can escape your tires, and your inflation pressure stays higher longer. Unfortunately, there are other possible sources of leaks (tire/rim interface, valve, valve/rim interface and the wheel), which prevent the guarantee of pressure maintenance for individuals using air or nitrogen inflation.

Nitrogen and compressed air CAN be mixed, if needed. Tires manufactured by Michelin are designed to deliver their expected performance when inflated with air or nitrogen, as long as the user respects the pressures recommended by the vehicle manufacturer on the vehicle’s placard or by the tire manufacturer.

Read our Frequently Asked Questions.

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You'll need a tire pressure gauge—a digital gauge gives the most accurate reading, though a quality analogue gauge works fine. Remove the valve cap, press the gauge firmly onto the valve stem, and read the pressure. Compare it to the recommended pressure on your vehicle's door jamb placard. If too low, add air at a gas station or with a portable compressor. If too high, use the gauge's release pin to release a small amount of air, then recheck. Replace the valve cap when done.

Underinflation is one of the most damaging things for a tire. The sidewall flexes excessively under load, generating heat that breaks down the internal rubber and cord layers over time. Underinflated tires wear faster on the outer edges, handle poorly in emergency manoeuvres, increase fuel consumption, and are at higher risk of sudden failure. A tire that's 20% underinflated can wear out significantly faster and has a meaningfully higher chance of failure at highway speed.

The Tire Pressure Monitoring System (TPMS) light—an exclamation mark inside a U-shaped tire symbol—illuminates when one or more tires falls 25% or more below the recommended pressure. At that point, the tire is already significantly underinflated. Don't wait for the light to check pressure—check monthly proactively. When the light comes on, check all four tires, inflate to spec, and investigate the cause. If the light stays on after inflating, have the TPMS system inspected—sensors can fail or need recalibration after a tire change.

For every 6°C drop in temperature, tire pressure decreases by approximately 1 psi. In Canada, a tire at the correct pressure on a 20°C October day can be 5–8 psi underinflated by January without any puncture. This is why many Canadian drivers find themselves adding air to their tires each fall. It's also why your TPMS light may come on on a cold morning and go off after driving—once the tires warm up, pressure increases. Check and adjust your tire pressure at the start of each season as temperatures change.

Tire pressure