Tire age doesn't determine service life, RMA study says

Washington, DC - A tyre'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 tyre processing facilities in seven states - Florida, Arizona, California, Oregon, Pennsylvania, Illinois and Massachusetts - to examine more than 14 000 tyres for date of manufacture, treadwear, road damage and repairs. The technicians discovered that treadwear was by far the most consistent determinant of a tyre's service life, with 59 percent of the tyres having low or uneven tread depth.

Twenty-nine percent of the tyres 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 tyre should be taken out of service."

The RMA has submitted the report to the tyre-aging docket at the National Highway Traffic Safety Administration, which is currently working on an aged tyre endurance test for its tyre performance standard.

From Rubber & Plastics News (A Crain publication)