Since 2000, the Department of Transportation (DOT) and the National Highway Traffic Safety Administration (NHTSA) have mandated manufacturing dates on all tires. Because the rubber composition of a tire can break down after time, even when it's not in use, this policy helps protect consumers from purchasing old tires that may fail under duress due to age. Learning this simple procedure will help you determine the age of the tires you're purchasing before you buy them, and it will also help you determine the age of the tires on your vehicle now.
Locate the full DOT tire number on the sidewall of the tire. This number will be between 10 to 12 digits long. If you are determining the age of a tire that's already on your vehicle, check the inside sidewall. If necessary, turn the steering wheel all the way in one direction and drive forward until you can locate and read the DOT number.
Find the last four digits of the DOT number. In most cases, it is separated from the other six to eight digits and stamped in an inset-capsule-shaped oval on the sidewall of the tire.
Read the last four digits to determine the week of the year and the actual year the tire was manufactured. For example, a tire with the last four digits "3609" would inform you that the tire was manufactured in the 36th week of the year 2009. A tire displaying the date code "1210" would inform you the tires were manufactured in the 12th week of 2010.
Inspect each tire (moving the vehicle if necessary or applicable) to educate yourself on the age of the other tires on the vehicle.
