Tires are constructed from materials such as rubber and fabric that lose their strength and flexibility over time. Often it is not possible to determine through visual inspection whether a tire is too old or dangerous. Tires are not manufactured with an expiration date, but it is possible to figure out if a tire is too old to use safely.
Look for the tire identification number branded in the sidewall of the tire. This ID number starts with the letters DOT followed by a combination of 10 to 12 letters and numbers. If you see DOT plus just a few letters or numbers, the full ID number is on the other side of the tire.
Note whether the last part of the ID number consists of three or four digits. If you see just three numbers, the tire was manufactured before the year 2000; jump to Step 5.
Decode the tire manufacture date. The four-digit number provides the week and year the tire was manufactured. For example, if the digits are 4308, the tire was manufactured in the 43rd week of 2008.
Determine the age of the tire by subtracting the date of manufacture from the current date. Remember that a year has 52 weeks and each month is approximately 4.3 weeks long.
Properly dispose of any overage tires. Consumer safety experts say a tire over 6 years old is too old to use safely.
