Temperatures will drop as we get deeper into December and January, and so will the air pressure in our tires. Science teachers taught us that air expands when heated and contracts when chilled, and this means there is less air pressure in your tires when the temperatures drop. Pima County Department of Environmental Quality (PDEQ) recommends checking your vehicle’s tire pressure when temperatures get chilly.
For every 10
degree Fahrenheit change in air temperature, tire pressure will change about 1-to-2 two pounds per square inch (PSI). This can result in a drop of about 5 PSI in the winter, which is enough to negatively affect vehicle handling, traction, gas mileage
and tire durability. Monthly tire pressure checks, along with a special tire-pressure check when temperatures drop suddenly, will improve driving safety, save you money at the gas pump and reduce tailpipe emissions.
Vehicles equipped with Tire Pressure Monitoring Systems warn drivers when tires are up to 20 percent under-inflated. This warning can be too late to prevent damage caused by under-inflation, so regular checks with a gauge are still important.
Where do you find the correct tire pressure for your particular vehicle? Don’t look for it on the side wall of the tire! That number is the maximum amount of air the tire can hold. Every vehicle has its own ideal PSI, which is usually printed on the inside of the driver’s side door jamb, in the trunk or the glove box. This PSI number also can be found in the owner’s manual. Maintaining your tires at the right pressure will:
- provide a smoother ride
- reduce tire drag, which wears tires out faster and causes the engine to burn more gasoline
- save you money at the gas station
- improve vehicle safety and handling
- reduce vehicle emissions for healthier air
PDEQ operates the Pima County Waste Tire Collection Facility and receives more than 60,000 waste tires for recycling every month! Proper tire inflation can prevent premature wear and the need for disposal at our facility. For more information on the benefits of proper tire inflation, visit the PDEQ Clean Air Program’s
Pump Up Your MPG campaign.