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How to tell if that 'new' tire is actually dangerously old

That set of 'brand new' tires you just bought could have been sitting on a shelf for years. Here's how to spot an aging tire.

Tires are easily the most underrated safety feature of any vehicle. For the average passenger vehicle, the contact patch (the part of the tread that actually contacts the road) is roughly about the size of your open hand. Those four relatively tiny contact patches bear a lot of responsibility. They provide the entire grip required to stop, steer and accelerate your vehicle.

Most motorists neglect their tires and fail to realize the significant role they play in motoring safety. The most common fault is not ensuring tires are properly inflated. Many motorists will shop for a less expensive alternative to their OEM tires, sacrificing handling qualities for a few dollars. Too many drivers will settle for the compromise of an “all season” tire for winter driving. On the other hand, a few auto enthusiasts will actually upgrade their tires to obtain improved handling characteristics and safety.

The bottom line is we should never take our tires for granted. Along with keeping them properly inflated, they should be frequently inspected for irregular wear patterns, punctures and tread life.

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There is also another very important, but less obvious feature of your tires you should be paying heed to, their age.

Tire rubber compounds are subject to degradation as they age. Exposure to ozone and ultraviolet light will harden and dry the rubber making it brittle. Signs of aging can be seen on the tire tread and side wall in the likes of small cracks in the rubber. This is a visual warning to you that any tire with cracks showing in the side wall or tread has reached the end of its service life and needs to be replaced.

Three significant problems arise with this aging. One, the tire rubber has hardened to the point where the level of grip is compromised. This will lengthen braking distances and reduce handling quality. Two, the rubber will become more porous allowing air to leak out quicker increasing the chances of the tire developing dangerously low tire pressures. Three, with the aging of the rubber compounds, the tire stands a greater risk of delaminating or coming apart.

This obvious aging of the tires on your vehicle is relatively easy to assess. You should not expect more that five or six years out of a set of tires. Any tire older than this will eventually be subject to dangerous degradation and should be replaced. A visual inspection of your tires will reveal these telltale cracks in the tread or side wall. Any tire exhibiting these traits should be replaced.

However there is also another danger that is less obvious. It too has to do with the age of the tire, but because these older tires have not been used their age is more difficult to ascertain.

An in-depth look into fatal crashes related to vehicle tires by ABC News 20/20 In Touch — “Aging Tires That look New” (see has revealed a growing concern in the U.S. regarding tire stores selling tires as “new” even though the code stamped on the tire indicates it could be actually more than six or seven years old. Visually, these tires do look brand new, but a code stamped on the side wall indicates some were built in the 1990s.

Investigators are linking some vehicle crashes, a number of them fatal, to the use of these “older” tires. The vehicle owners bought them recently, believing they were purchasing a “new” tire. Even though the tire was built almost a decade ago, it could be sold as “new” simply because it had never been mounted on a rim and used.

In North America, there is no “Expiration Date” stamped onto new tires and they can sit around in a warehouse or tire store for years deteriorating from age with no visible indication. In Britain, the BRMA (British Rubber Manufacturers Association) “strongly recommends no tire should be used six years after it was made.” Some vehicle manufacturers such as Ford have lobbied the U.S. government to put a six-year expiry date on tires. The NHTSA has also acknowledged that tire age is a significant factor in safety.

There is a code on the tire that can tell you what the date of manufacture was. It is a four digit number usually near the DOT stamp in an elongated oval that when deciphered will tell you the week and year of manufacture. For example, the code 3002 will tell you this tire was made in the 30th week of 2002. The number 0104 indicates a manufacture date of the first week of 2004. The tire in our photo has a code of 0407 and was built in the 4th week of 2007.

Your tires are a very important part of your vehicle safety. For your sake and that of your passengers, do a little research to be sure you are not compromising your safety when replacing your tires.

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