With lawsuits on the rise and continued widespread media attention, Rumberger, Kirk & Caldwell attorney Brian Baggot talks about several issues that tire manufacturers and auto dealers face regarding aging tires.
Related Questions
As with everything in life, tires cannot be expected to last forever. To specifically answer this question though, it might help to understand a little bit about how tires are made. During tire manufacture, rubber is bonded to layers of fabric (called "plies") and steel cords. Even though anti-aging chemicals are added to the rubber compounds during the manufacturing process, oxidation of a tire will occur over time as air and moisture permeate through the tire's inner liner. This can ultimately undermine the bond between the tire's rubber, fabric plies, and steel belts. In rare instances, this "degradation" can produce a tread / belt separation and the failure of the tire on the road. Usually however, tire treads wear out well prior, prompting the consumer to replace the worn tire long before it could become too old for continued service.
Every tire has a "birth date" listed at the end of the data following the "DOT" letters on the sidewall. - In this photo, the numbers in the red box indicate the tire's birth date:
The digits "5107" show that the tire was made during the 51st week of 2007 or, sometime between December 17-23, 2007. The manner in which this "birth date" is written on the sidewall is required by Federal law and the U.S. Department of Transportation prohibits tire manufacturers from writing this date in any other format.
Unfortunately it is impossible to predict when tires should be replaced based on their calendar age alone. The consumer's use and maintenance of the tire play the primary role in whether the age of the tire affects its serviceability. Such factors include improper inflation, routine high speed driving, failure to maintain proper wheel alignment or rotation patterns, and carrying excessive loads. Additionally, environmental factors such as the level of sunlight exposure and other atmospheric elements also play a big role in the rate at which a tire ages.
The complexities of identifying all the variables that influence the rate at which a tire ages and quantifying their true influence on the tire's service life make it impossible to identify a uniform tire expiration date. Even today, there is simply no consensus within the tire industry or with government regulators as to the point at which age affects a tire, the chronological age when a tire should be deemed unserviceable, or even if there is a suitable test for determining if a tire is too old for continued use. Even NHTSA, the U.S. National Highway Traffic Safety Administration, has been "unable to develop a workable test" after more than three years' study, to reliably determine the point at which the age of a tire has an effect on "real world safety."
Unfortunately, an arbitrary tire expiration date would have its own negative, unintended consequences.
An expiration date would, in some cases, discourage vehicle owners from the regular, vigilant inspections or maintenance of tires that had not yet reached such date. And, if consumers interpret the expiration date as the only determinant of a tire serviceability, they might fail to perceive other physical signs of looming tire failure unrelated to the age of the tire, such as unusual tread wear, problem valve stems, penetrations, or damage from collisions and other road hazards.
Moreover, the establishment of arbitrary tire expiration dates will, in tens of thousands of instances, result in perfectly good tires being prematurely scrapped, thus contributing to increased operating costs, waste, and environmental pollution.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
