How To Find Your Tire Size & Correct Air Pressure

We recommend going to the tire opposite (across) of the one that needs to be replaced. So if your front driver side tire is flat, go to your passenger front tire to check the size.

Always remember to check your door jam, which will show you helpful information such as proper tire size and air required.

Knowing the correct tire size and proper air pressure for your vehicle is essential for safety, handling, and tire life. Many drivers rely on guesswork, but your vehicle already provides the information you need. Here’s how to find the right tire size and air pressure quickly and accurately.

Where to Find Your Correct Tire Size

Your vehicle’s tire size is not a guess — it’s specified by the manufacturer.

Driver-Side Door Sticker

Open the driver-side door and look for a sticker on the door frame. This label shows:

• Factory tire size

• Recommended cold tire pressure (PSI)

• Front and rear pressure specifications (if different)

This is the most reliable source for your vehicle’s tire information.

Understanding Tire Size Numbers

A tire size looks something like 225/45R18. Each part has a meaning:

• 225 – Tire width in millimeters

• 45 – Sidewall height as a percentage of width

• R – Radial construction

• 18 – Wheel diameter in inches

Using the wrong size can affect braking, handling, and speedometer accuracy.

How to Find the Correct Tire Air Pressure

The correct air pressure is not printed on the tire itself.

Use the Vehicle Sticker, Not the Tire

The PSI listed on the tire sidewall is the maximum pressure, not the recommended pressure. Always follow the PSI listed:

• On the driver-side door sticker

• Or in the owner’s manual

This ensures proper traction, comfort, and even tire wear.

Why Tire Pressure Changes Over Time

Air pressure naturally changes due to:

• Temperature swings

• Seasonal weather changes

• Normal air loss over time

Cold weather can lower tire pressure, while warmer temperatures can raise it. That’s why checking pressure regularly is important.

When to Check Tire Pressure

For accurate readings:

• Check tire pressure when tires are cold

• Avoid checking immediately after driving

• Use a quality tire pressure gauge

Regular checks help prevent uneven wear and reduce the risk of tire damage.

What If Your Tires Don’t Match the Sticker?

If your tire size doesn’t match the door sticker:

• The vehicle may have aftermarket wheels

• A previous owner may have changed sizes

• The spare tire may be a different size

In these cases, having a professional verify the correct size and pressure is recommended.

Need Help Checking Tire Size or Pressure?

OnSpot Tire & Auto can help verify tire size, check air pressure, and address tire-related issues on-site.

📞 Call OnSpot Tire & Auto at 703-962-6616🚗 Mobile tire service with 24/7 emergency services available