Tires lose pressure gradually over time. Underinflated tires can reduce a vehicle's gas mileage and handling and the tires' lifespan. Because tire pressure affects the safety and performance of your vehicle, check your vehicle's tire pressure with an accurate tire pressure gauge at least once a month, advises SaferCar.gov, a website maintained by the U.S. Department of Transportation. Visually checking tire air pressure is not sufficient.
Tires lose a small amount of air on a daily basis through the process of permeation. The outdoor temperature affects the rate of permeation. Drivers.com states that tires lose approximately 0.454 to 0.907kg. of air each month during cooler months. During warmer months, tires lose air at a faster rate.
When a vehicle tire hits a curb or other rigid object, the impact may cause the tire to lose pressure. Driving over potholes or speed bumps can also cause tires to lose air suddenly. Check the tire pressure as soon as possible whenever your vehicle's tires suffer any sort of impact. Visually check the tires for any damage.
Nails, screws and other sharp objects can create a minor puncture in a tire, causing it to lose pressure slowly. Visually inspect your tires on a regular basis to check for embedded objects that may create a slow leak. If you notice that a tire is suddenly vibrating or that your vehicle is pulling to one side, or if you hear a ticking sound coming from a tire, this may indicate that an object has become embedded in one of your vehicle's tires. Bring the vehicle to a tire dealer as soon as possible to inspect and potentially repair or replace the tire.
Temperature and Altitude Changes
A sudden drop in temperature will cause a drop in tire pressure. For every -12.2 degrees Celsius the temperature drops, tires lose 1 to 2lbs. of air. Major changes in altitude also affect your vehicle's tire pressure. When you travel from a high-altitude location to a significantly lower elevation, tire pressure is lost, according to Tire Rack.