http://cbs5.com/news/local/2004/11/09/Special_Report%3A_Check_the_Age_of_Your_Tires.html
[I]How old are your tires? Not when you bought them, but their actual dates of manufacture. Experts say tires age – whether they’re on the road, in your trunk or sitting in a warehouse waiting to be sold — and the rubber slowly deteriorates.
A growing number of safety experts are calling for expiration dates on all tires, although tire makers argue their products age at different rates depending on conditions.
Rhonda and Mark Zarzaur, for example, bought four new tires for their car. But, what seemed new to them, wasn’t really new at all. The treads started separating on all their tires. Rhonda did some research and found that, while she bought her tires unused, at least one was manufactured more than a decade before she bought it.
Safety expert Sean Kane says he’s compiled dozens of accident cases involving either serious injury or death following tread separation due to old tires. “The glue that holds the belts together becomes less viable,” says Kane.
How old is too old? Kane say six years past the date of manufacture. He’d like to see expiration dates. But tire makers argue there’s no way to determine a blanket date, because factors such as storage, maintenance, and weather affect the aging process.
Federal studies are currently underway. The National Highway Traffic Safety Administration (NHTSA) is so concerned it’s currently conducting tests on how tires age.
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[B]
How to Check the Age of Your Tires
According to Kane, there’s no easy way to find out the exact age of your tires, but in most cases you’ll be able to tell if your tires are at least 10 years old with a little bit of research.
Step 1: Get under your car
The Department of Transportation (DOT) code that contains your tires age is on the sidewall of each tire, usually on the inside.
Step 2: Determine type of code
There are two types of codes: one that has 11 numbers and contains letters and one that has 10 numbers and letters.
Step 3: Decipher code
For codes with 11 numbers: Note the last four digits. The first two numbers signify the week and last two signify the years. For example “35-03” means the tire was made the 35th week of 2003.
For codes with 10 numbers: Note the last three digits: The first two signify the week and the last one signifies the year. For example “4-1-4” means the 41st week of either 1994 or 1984 – there is no way to know which decade from the DOT code.
Step 4: Get Help
If you are concerned that your tires are too old, or have trouble deciphering the DOT code, get help from a local automobile center or dealership.[/B]