Research data has also shown that the under-inflation of a vehicle's tires by just 10 pounds per square inch (psi) reduced the fuel economy of the vehicle by a noteworthy 3 percent.
So, in an everyday example, if the tires on a vehicle should be inflated to 35 psi and they are only inflated to 25 psi, instead of getting the manufacturer’s suggested 20 miles to the gallon, the driver is only getting a mere 19.4 miles to the gallon.
Let’s say you own that car with the 20 gallon tank; you should be getting 400 miles per tank. Instead of getting 20 miles per gallon, you are only getting 19.4 miles per gallon due to your under-inflated tires, which means you are only getting 388 actual miles out of that 20 gallon tank.
At $3 a gallon, you’ve just evaporated $36 by not having properly aired tires. If you fill up once a week, you’ve just wasted $144 that month alone.
How does a regular guy (or gal) check tire pressure? First by looking at the writing on the outside wall of your tires, your owner’s manual, or the inside of your vehicle door jamb for recommended inflatable psi.
Next, going to Wal-Mart and parting with the $5 it costs for the air pressure gauge, which sometimes will even include instructions on its use! Air is usually free at your local gas station, and it only takes a few minutes to perform the routine check.
For the best results, check your pressures once a month, and listen to the money jingle in your pockets instead of hearing moths fly out of your wallet.