The U.S. tire industry is refusing to give American motorists the same warning given to car owners in Europe and Asia about the possible dangers of tires six years old or older.
More than 100 deaths in the U.S. have been attributed to aged tires which dried out and lost their treads, even though they appeared to be safe, according to Sean Kane, who heads a private auto safety firm and consults with the federal government.
With no warning from the industry or the federal government, safety experts say the only way for consumers to protect themselves is to learn how to read the cryptic code embedded on a tire's sidewall which reveals the year and week a tire was manufactured.
The code is at the end of a jumble of letters and numbers on the tire and, until recently, was on the inward side of the tire requiring motorists to climb under the car to read the number.
For example, the number 418 indicates the tire was manufactured in the 41st week of 1998 and is 10 years old.
"U.S. consumers are left in the dark on this issue," said Kane.
A tire older than six years old, even if it's never been driven a mile, "is like a ticking time bomb. You don't know what's going on inside. That's what makes it so dangerous," said Kane in an interview for broadcast on "20/20."
Members of the British Rubber Manufacturers Association, which include Goodyear, Firestone and Michelin, warned in 2001 that "unused tyres [sic] should not be put into service if they are over 6 years old."
The U.S. tire industry association, representing many of the same companies, says it has no plans to issue a similar warning.
"There's no scientific information that can point to when a tire should be removed because of age," said Dan Zielinksi, of the U.S. Rubber Manufacturers Association, who maintains that age is not the key factor in tire safety and performance. "You need to look at the totality of the tire's service life or its storage conditions to make that decision."
But safety experts say there is extensive research showing tires begin to deteriorate in "critical" ways even if they remain unused or unsold in store inventories.
In most cases, a visual inspection or check of tread depth will not reveal the problem, the experts say.
The Ford Motor Company has urged the federal government to adopt a six-year expiration date, citing "comprehensive research" and "defendable data driven by analysis."
Ford, BMW, Chrysler, Toyota and VW/Audi now carry warnings about aged tires in manuals given to car owners.
Even some tire companies have begun to issue warnings. Bridgestone/Firestone, Michelin and Continental now recommend that tires older than 10 years should not be used, even if they appear safe by visual inspection.