WASHINGTON (May 23) — A tire´s chronological age alone cannot determine whether it should be removed from service, according to a study just issued by the Rubber Manufacturers Association.
The RMA sent teams of technicians to scrap tire processing facilities in seven states — Florida, Arizona, California, Oregon, Pennsylvania, Illinois and Massachusetts — to examine more than 14,000 tires for date of manufacture, treadwear, road damage and repairs. The technicians discovered that treadwear was by far the most consistent determinant of a tire´s service life, with 59 percent of the tires having low or uneven tread depth.
Twenty-nine percent of the tires were damaged, and 17 percent had repairs, 87.5 percent of which were improperly done, according to the RMA. The time line for the service removal dates was a smooth curve with no spikes, noted Laurie Baulig, RMA general counsel.
"This is what industry engineers would call a ´Natural Decay´ curve," Baulig said. "This shows there is no potential ´magic date´ by which a tire should be taken out of service."
The RMA has submitted the report to the tire-aging docket at the National Highway Traffic Safety Administration, which is currently working on an aged tire endurance test for its tire performance standard.