Tires are better at resisting wear than they were in 2000, when Firestone recalled millions of tires that were prone to lose their tread and blow out, according to federal data released Thursday.
But tire ratings for traction performance and heat resistance have seen little change since 2000, the National Highway Traffic Safety Administration said.
Six percent of tires rated between a 500 and a 600 on resisting wear this year, meaning they can last four to six times longer than a basic tire, and at least 25 tires had a rating of 700 or higher. In 2000, there were hardly any tires with a 600 and no tires with a 700.
NHTSA has been rating tires since 1980, but made its Web site easier to search this year in response to a call from Congress to make tire information readily available to consumers. There are ratings for more than 2,200 tires, including some that have been discontinued but may still be on store shelves.
“The more information they have, the better choices they’re going to make,” said Daniel Zielinski of the Rubber Manufacturers Association, which represents tire manufacturers.
Three percent of tires got the highest “AA” rating for traction and 75 percent earned an “A” rating in 2004, about the same as in 2000. Traction is tested on a wet surface in a straight line; NHTSA doesn’t test the tire’s performance in a sharp curve.
The majority of tires — 59 percent — were rated “B” for heat resistance in 2004. Fourteen percent of tires got the lowest rating of “C,” the same rating as the Firestone Wilderness AT tire that was recalled in 2000. Tire heat was a contributing factor in some of the 271 U.S. traffic deaths linked to Firestone tires, most of which happened in hot climates.
Tire makers conduct own tests
Manufacturers do their own tire tests, comparing their tires to a NHTSA control tire, and then place the ratings on the sidewalls of their tires. NHTSA does spot checks throughout the year to make sure ratings are accurate, spokesman Rae Tyson said.
NHTSA stressed that the tires aren’t rated for safety, and said owner maintenance, driving style, climate and other factors can have a significant impact on a tire’s performance.
Ratings also may reflect certain uses for a tire. For example, only one line of tires — the Goodyear Eagle GS-CS — got the lowest rating of “C” for traction in 2004. Goodyear explained that the tire is for racing and isn’t sold to general consumers. High-performance tires also may have low traction, but that’s because they are primarily designed to withstand the heat of fast driving.
“People really need to buy the right tire if they want to ensure their safety,” Zielinski said.
Joan Claybrook, who introduced the rating system when she was NHTSA’s administrator and now heads the consumer advocacy group Public Citizen, said the system has improved tire safety. But she said tire manufacturers should have to display the date the tire was made so older tires could be discarded.
Tire manufacturers have resisted that move, saying there are too many variables that affect aging.
