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Are your tires out of date?
Even previously unused tires can fail just because they are too old, safety researchers say.
November 8, 2004: 2:34 PM EST
By Peter Valdes-Dapena, CNN/Money staff writer

NEW YORK (CNN/Money) - Auto tires degrade with age, even if they are never used. So an auto safety consulting firm has petitioned the National Highway Traffic Safety Administration to require that all tires, like milk, have a clearly printed "born on" date.

Safety Research & Strategies, Inc. (SRS) of Rehobeth, Mass., has officially petitioned NHTSA to require the dates on tires and, in the meantime, to issue a consumer advisory that tires older than six years not be used.

A spokesperson for NHTSA said the agency has not had a chance to review the petition and could not comment on it.

The agency is currently conducting tests to devise a tire aging test to simulate aging tires under laboratory conditions, said Rae Tyson, a NHTSA spokesperson. With that test in place, the agency could set regulations regarding tire age.

A 2002 NHTSA proposal for a tire aging test was withdrawn because the agency found that further research was needed, Tyson said.

The date of manufacture is currently visible on tires as part of the tire identification number or serial number. The last four digits of this number -- which is up to 12 digits long and usually embossed near the inner edge of the sidewall on one side of the tire -- indicate the week and year of it was made. For example, the numbers 1501 indicate the 15th week (April 9 through 16) of the year 2001, according to a guide provided by the Rubber Manufacturers Association.

The SRS petition sites 37 fatalities and 35 serious injuries because of unused or little-used tires failing after being installed and driven on for a relatively short time. Data on these cases was gleaned from lawsuits involving these tire failures.

The owners manuals of some cars, particularly German ones, warn against using older tires, according to the SRS petition. That's the result of research carried out in Germany, which found mark increases in the failure rates of tires as they aged, regardless of the remaining tread depth. According to the petition, the problem is worst for tires stored for an extended period of time.

The British Rubber Manufacturers Association recommends that unused tires not be installed if they are more than six years old, according to the petition.

There is currently not enough scientific data on which to base recommendations about tire age, said Dan Zielinski, a spokesperson for RMA, the tire manufacturing industry group.

An undue focus on tire age could simply confuse consumers who already have trouble following proper maintenance regiments for tires, he argued. Improper maintenance is a much greater problem than the simple aging of properly stored tires.

"We have research showing that 70 percent of people never check the pressure in their spare tire," said Zielinski.

While it would be difficult or impossible to provide a meaningful "use by" date based on current research, Zielinski acknowledged that the rubber in tires does degrade with storage over time.

"It's certainly an issue worthy of discussion," he said.

One concern with concentrating on a tire's age is that it might lead consumers to think that a tire will be usable until that date, rather than viewing the date as the absolute upper limit, said John Rastetter, director of tire information services for TireRack.com, a tire retailing Web site.

Tires usually don't last six years if they are used and unused spare tires can fail for a variety of reasons, he said. Spare tires are often under inflated and, especially on trucks and sport/utility vehicles, they are often kept attached to the outside or underside of the vehicle's body where they are exposed to elements and heat.

For example, the rubber in a tire attached the back of an SUV can reach 135 degrees on a 65 degree day, Rastetter said.

Whenever driving on a spare tire, particularly one that is several years old, drivers should use caution and drive slowly until they have had the tire properly inspected and repaired if needed, Rastetter said.  Top of page




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Most stock quote data provided by BATS. Market indices are shown in real time, except for the DJIA, which is delayed by two minutes. All times are ET. Disclaimer. Morningstar: © 2018 Morningstar, Inc. All Rights Reserved. Factset: FactSet Research Systems Inc. 2018. All rights reserved. Chicago Mercantile Association: Certain market data is the property of Chicago Mercantile Exchange Inc. and its licensors. All rights reserved. Dow Jones: The Dow Jones branded indices are proprietary to and are calculated, distributed and marketed by DJI Opco, a subsidiary of S&P Dow Jones Indices LLC and have been licensed for use to S&P Opco, LLC and CNN. Standard & Poor's and S&P are registered trademarks of Standard & Poor's Financial Services LLC and Dow Jones is a registered trademark of Dow Jones Trademark Holdings LLC. All content of the Dow Jones branded indices © S&P Dow Jones Indices LLC 2018 and/or its affiliates.