The U.S. Department of Energy estimates that gas mileage can be lowered by 0.4% for every 1 PSI (pound per square inch) drop in the pressure of all four tires.
The Rubber Manufacturers Association states that 85 percent of drivers surveyed do not check their tire pressure properly, and many don't even know where to find the recommended proper tire inflation for their vehicle.
Visit our Free Air Check page for more information.
*Calculations based on US Department of Energy gas consumption estimates and assumption that underinflation value persists unchanged throughout the year.
--dtc106-- Known in Oregon & Parts of California as America's Tire