01Use the TIN to Determine the Age of Tires
The U.S. Department of Transportation (DOT) requires all tire manufacturers to stamp a Tire Identification Number (TIN) into the sidewall of each tire. This number starts with DOT and is followed by a series of 10, 11 or 12 letters and/or numbers. If your tires were manufactured after 2000, the last four digits of the TIN indicate the week and year that the tire was manufactured, with the first two numbers indicating the week and the last two indicating the year.
Refer to the photo above, and you'll see the numbers "2911." This indicates that the tire was made the 29th week of 2011, or sometime between July 18 and July 24, 2011. Easy, right?
And it's still easy if your tires were manufactured before 2000. Just look at the last three digits in the TIN to determine the age. The first two numbers are the week of manufacture and the last number is the year. So, if you had the number "329", that would indicate that the tire was made in August of 1999 (or at least that's what you'd have to assume). The DOT added the fourth number because the "9" could also indicate 1989, 1979 or even 1969. It just isn't as precise as it needs to be.
What If My TIN Number Isn't As Long as It's Supposed to Be?
If your TIN number consists only of the letters DOT, followed by four letters or numbers, check the other side of the tire. Manufacturers are required to list the entire TIN on one side of the tire, but they only have to list the first part on the other side.
What Do All of Those Other Letters and Numbers Means?
The "DOT" indicates that the tire was tested and found to conform to U.S. Federal Motor Safety Standards. The next two numbers are the manufacturer plant code. The two after that are the tire size code, and the four numbers preceding the date code are the manufacturer code. So, you can actually learn quite a bit from that TIN.
02Why Should I Care How Old My Tires Are?
There are several reasons you should care. First, it's a matter of safety. The Department of Transportation recommends replacing tires after 10 years – even if they have good tread. Exposure to UV rays and other environmental conditions causes the rubber to break down over time. This could lead to a blow out, and cause an accident.
Another reason you should care? It'll make you an informed consumer. If a retailer tries to sell you an old set of tires, you'll be able to tell right away. Insist on a fresh set. You don't want that set that's been baking in the back of a hot warehouse for the past three years.
And the final reason? Tires come with mileage and age warranties. If your tires wear out before they should, they'll prorate your next set. Save your receipt, so you're covered.
03Need to Replace Your Tires Now That You Know How Old They Are?
How to Tell How Old Your Tires Are
You may know how to check the tread depth of your tires, but do you know how to check their age? If not, this is one skill that you need to add to your arsenal, and it'll take you all of two minutes to learn.