WASHINGTON -- Tires made for passenger cars and light trucks will be required to withstand new speed and endurance tests by 2007 in the first new federal safety standards for tires since 1967.
Congress ordered the National Highway Traffic Safety Administration to make the changes in 2000 after the recall of millions of Firestone tires.
"Without question, these new performance requirements will improve tire safety," said NHTSA Administrator Dr. Jeffrey Runge.
Most tires on the market already comply with the new standards. NHTSA estimated that 5 to 11 percent of tires will have to be redesigned or modified to comply.
The new requirements are expected to cost tire manufacturers $31.6 million, NHTSA said. The agency estimates they will save at least four lives and prevent 102 injuries each year.
Under the new criteria, tires must be tested at 87, 93 and 99 miles per hour for 30 minutes at a time. That is an increase from the current test of 75, 80 and 85 miles per hour. A tire will be considered compliant if there is no visual evidence of tread separating or cracking after the test, and the tire pressure isn't lower than the initial pressure.
Tires also will be tested for endurance in a 34-hour test. That test will run tires at 75 miles an hour for four hours, carrying 85 percent of the tire's maximum load, six hours with 90 percent of the maximum load and 24 hours with 100 percent of the maximum load. That test speed is 50 percent higher than the current test and 50 percent longer than the current distance.
The standards also include a new test to ensure performance even if a tire is underinflated. The test, designed to mimic long-distance family travel, runs the tire for 90 minutes at 75 miles per hour at the level of underinflation that sets off a vehicle's tire pressure warning system.
NHTSA didn't adopt several other tire safety proposals it was considering, including one for checking the strength of a tire's performance on hazardous roads. The agency said it also didn't adopt another test that measured the effects of aging, but it is working with tire manufacturers to develop such a test.
Under the rules NHTSA originally proposed, the agency estimated that 30 percent of tires wouldn't pass and costs to tire makers would approach $300 million. Still, NHTSA said the new standards are reasonable ones "based on the best currently available information."
Goodyear Tire & Rubber Co., the world's largest tire manufacturer, and Bridgestone-Firestone referred questions on the proposals to the Washington-based Rubber Manufacturers Association.
RMA spokesman Dan Zielinski said response so far is mixed. The group is pleased that NHTSA is holding off aging and hazardous road tests because it believed there wasn't enough data for those. It wanted light trucks tested at lower speeds -- a request that NHTSA didn't honor.
Tire manufacturers are required to meet the new standards by June 1, 2007. Manufacturers conduct NHTSA's required tests in-house, and every type of tire must pass in order to be sold in the United States.
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