Tires are the only contact that your vehicle has with the road. They can affect your gas mileage. With today's gas prices everyone wants to get the best gas mileage out of their vehicle. Making sure the tires are filled to the correct PSI is one of the easiest ways. Under inflated tires have an increase of friction and cause uneven wear on your tires. To keep the tires in the best shape possible it is best to rotate them every 5,000 miles. In addition, having oversized tires for your vehicle can also affect the gas mileage of the vehicle. Oversized tires also create more friction and weight on your wheels, now times that by four. That adds up quickly and will cause reduced fuel economy. With gas prices where they are now, we want to get everyone the best fuel economy.