So you've just paid a few hundred dollars to have all four tires replaced and they look great. You're ready to take off and see how these tires grab the road. Before you do, check the age of your tire. Just like an old rubber band that dries, gets brittle and then snaps when the least amount of pressure is exerted, you're tires could be under the same condition. For all you know, you could be driving on 4 time bombs.

Here's what tire manufacturers don't want you to know. There is coding on the side of a tire. For example:

DOTMK87FOWR4202

Most people would not know what this 12-digit DOT serial number means, but you will shortly.

DOT - Department of Transportation approved tire
MK - DOT's tire plant code
87 - Tire size code
FOWR - Tire brand
42 - 42nd week of year
02 - 2002

If the tire you bought only has 3 numbers instead of four like the example above, then the tire was created in the 1990s. For example, a tire with the numbers 414 was made during the 41st week of 1994. All tires made after 2000 have four numbers.

Tire experts say that you should not be using tires that are 6 years or older. So the next time you are ready to buy new tires, ask to see the DOT serial number. And if the tire store really wants your business, they'll get you some new tires. If they won't, time to find another store.