Determining the Age of a Tire

There are two reasons why you might want to determine the age of a tire. The first, of course, would be to find out the month and year that tire was manufactured. This information is relatively easy to ascertain. The second reason would be to determine how long that tire has been in use. This is slightly more difficult.

Determining the Age of a Tire by Manufacturing Date

Just as vehicles are assigned VINs (vehicle identification numbers), tires are assigned TINs (tire identification numbers). They are used for basically the same purpose: to track the manufacture of that tire to a specific place and time.

According to TireRack.com, it's easy enough to decode your tire identification number. The last four digits (three if manufactured before the year 2000) indicate the age of the tire. For example, if the tire identification number is 3608, the tire was manufactured in the 36th week of 2008.

Determining the Age of a Tire By Wear

Perhaps the manufacturing date means little to you. You simply want to know how long the tire has been in use-or perhaps how much longer you can continue to use it safely. There is no magic formula for this answer, but you can make an educated guess.

Tire tread is the easiest way to determine the age of a tire, and how long you can continue to drive on it. I was taught the penny trick: stick a penny into the tread of the tire upside down. If you can still see Lincoln's head, the tread is too worn and the tire should be replaced.

Of course, several factors can influence tread wear besides the age of a tire. The frequency of use, the terrain on which you drive, and the alignment of the vehicle are just a few. If tires aren't properly balanced and rotated, tread might also wear more quickly.

Tire Shelf Life

There is some controversy about the shelf life of tires, according to MSNBC, but it pays to check the tire identification number before you leave the store. If you are sold an older tire, it might have lost some of its structural integrity, resulting in a significant safety risk to anyone behind the wheel.

The same goes for tires you might have left sitting around your garage at home. Using a tire after six or seven years could be dangerous, particularly if it was left in a non-climate-controlled environment where pests, mold, and other problems could have weakened it. In other words, the age of a tire matters, but there are other factors to consider.