As the adage goes, everything’s riding on your tires. Thus, when it comes to vehicle safety, nothing’s more important. Tire failures can result from a design or manufacturing defect, or the tire may simply be too old to withstand the heat and pressure of the road, regardless of tread. The recall of defective Firestone tires brought the tread separation and belt adhesion issues into the public spotlight, resulting in heightened public awareness, and no doubt countless lives saved. Americans love to drive, and as frequent drivers, knowledge of potential tire defects is critical to safety on the road.
Tire Aging
The dangers of “aged” tires, while beginning to come more into public view, remains a little known problem outside of the industry and one that could be the cause of a significant number of tread separation problems. “Aged” tires are often unsuspectingly put into service after having served as a spare, stored in garages or warehouses, or simply used on a vehicle that is infrequently driven. In many instances these tires show no visible sign of deterioration, and absent any visible indicators, tires with adequate tread depth are likely to be put into service regardless of age.
Physical and chemical properties of tires change over time, regardless of use. Studies show that tire performance can start to degrade after six years – even if tires haven’t been used. According to SRS, Inc. a Massachusetts-based auto-safety research firm, 108 accidents are linked to tread separation of tires more than six years old, which resulted in 85 deaths.
NHTSA is conducting tests on new tires to determine their durability and developing future tests to simulate aging. The agency will begin requiring manufacturers to print the manufacture date on tires in September 2009. BMW AG, Ford Motor Co., DaimlerChrysler AG, Toyota Motor Corp. and Volkswagen AG have all backed guidelines that tires should only be in service six years.[1]
Tire Tread Separation
When a radial tire suddenly loses its tread, the driver often loses control of the vehicle. A blowout of the tire, or rapid pressure decrease in the remaining core, is often associated with a loss of tire tread and drastically increases the chance of a rollover accident. As seen in the Firestone tires that were widely recalled in 2000, tread separation occurred due to adhesion problems between the steel and rubber in steel-belted radial tires.[2]
The treads may separate because of a defect that occurred in either the manufacturing or the design process for that tire.[3] For example, the fusing which occurs during vulcanization may not have fused completely or properly. Also, however, time, and the physical changes the tire undergoes over time, reduces the effectiveness of the bonding and adhesion of the tread to the tire, thus facilitating a tread separation.[4]
How Old?
Many consumers will see a tire and think that it looks brand new. However, the actual manufacturing date of the tire may be quite different from the purchase date. Tire age degradation has been an “open secret” within the industry for years, and in June 2008 NHTSA finally issued a warning for consumers regarding the hazards of old tires.[5] This warning stated that even though tires may appear to be brand new, they can lead to “catastrophic failure.”[6] The warning includes steps to use to determine a tire’s age, since the DOT code on the tire is a “consumer unfriendly” formula as opposed to just a date stamp.[7]
Consumers must decode the DOT number on their tires as opposed to calculating from the purchase date of the tire because tire retailers are selling tires as “new” that are actually much older. In May of 2008, a group of reporters in California set out to see how old the tires that were being purchased really were.[8] They found several retailers selling tires that were up to twelve years old.
Age Does Matter
Safety experts and NHTSA have taken the position that tires that are over six years old can be “catastrophic.” This is true even if the tire has not been used for all of those years. The chemical and physical components of a tire make it a product that changes over time. The dangers of a tread separation, which could cause vehicles to lose control and crash or roll over, are very serious. Consumer must keep their tires safe, not only by the routine maintenance of checking the tread length and air pressure, but by decoding the DOT code on the tires they have and are purchasing. Litigation is ongoing against tire manufacturers and retailers for manufacturing and design defects as well as for tread separations because of tire aging.
References
[1] Robert E. Ammons, The Invisible Danger of Aging Tires, Trial, Auto Cases (April 2005).
[2] Id.
[3] Id.
[4] Id. (noting the effects of the change in chemicals over time on the effectiveness of the bonding of the tire layers together).
[5] Joseph Rhee, New Warning: ‘Catastrophic Failure’ Discovered in Aged Tires, ABC News, http://abcnews.go.com/print?id=4988518 (June 3, 2008).
[6] Id.
[7] Id. This “code” is likely just another way to keep consumers in the dark on how old the tires they are purchasing as “new” really are.
[8] Asa Eslocker & Joseph Rhee, ABC News Hidden Camera Investigation: Aged Tires Sold as ‘New’ by Big Retailers, ABC News, http://abcnews.go.com/print?id=4822250 (May 9, 2008).
