Where to find the recommended PSI number for your vehicle
Do you know how much air pressure your tires need? It’s written somewhere, not just in the instruction manual.
As temperatures drop, so does tire pressure.
According to the Old Farmer’s Almanac, in many parts of the country, the average date of the first frost has passed and the cold nights of fall are already creeping in.
According to the American Automobile Association, as temperatures drop, tire pressure can decrease by 1 to 2 pounds per square inch for every 10 degrees of temperature drop.
“This is simply due to how air molecules react to changes in temperature,” said David Bennett, senior automotive manager at the American Automobile Association (AAA). “In cold weather, air molecules move more slowly and the air pressure decreases.”
Under-inflated tires can increase stopping distances, reduce road grip and reduce fuel efficiency, Bennett said.
How to check tires
AAA recommends checking tire pressure using a tire gauge.
Gas stations may provide air pumps, and AAA warned that those pressure gauges can be damaged by exposure to the elements or overuse.
Additionally, drivers are advised to check tire pressure after the tires have cooled, typically three hours after driving, then remove the valve stem cap and press the gauge against the system.
According to the AAA, there are three types of pressure gauges.
- Stick pressure gauge: About the size of a pencil, this gauge forms a rod that slides out of the valve when you push the gauge into the system. It’s relatively inexpensive and easy to store in the glovebox, but it can be difficult to read.
- Dial pressure gauge: Used in the same way as a stick pressure gauge, but more expensive and difficult to store in the vehicle. Similar to a blood pressure cuff, the dial pressure is easier to read than a stick pressure gauge.
- Digital pressure gauge: The most accurate of the three. Dial pressure gauges have an electronic screen instead of a stick or dial.
Check tire pressure without a gauge
In situations where you don’t have a tire pressure gauge, there are several things you can do to identify underinflated tires.
- Examine the wheels. Tires flex where the rubber makes contact with the road.
- How your wheels feel: If your tires hurt when you press on them, the air pressure may be low.
- Add weight to your vehicle: If your tires seem to flatten when you add weight to your vehicle, your tires may be underinflated.
- Changes in handling: If your car doesn’t drive smoothly, bumps more than usual, makes steering noise, or has difficulty turning, your tire pressure may be low.
- The most accurate way to check tire pressure without using a tire gauge is to take your vehicle to a mechanic.
Tire pressure can be adjusted at home using an air pump or air compressor. Additionally, drivers can refill their tires for a small fee at gas stations offering aviation services.
