NHTSA proposes passenger and light truck tire performance standard

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The U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA) is asking for comments on a new proposal requiring more stringent tire performance requirements.

The resulting new federal motor vehicle safety standard (FMVSS No. 139) would apply to all new tires for use on vehicles with a gross vehicle

weight rating of 10,000 pounds or less.

"In developing this proposal, NHTSA placed particular emphasis on improving tires to withstand the effects of factors mentioned during the consideration and enactment of the TREAD (Tire Recall, Efficiency, Accountability and Documentation) Act -- tire heat build up, low inflation, and aging," said Dr. Jeffrey Runge, NHTSA Administrator.

"We have identified an array of amendments for revising and updating our tire standards

and improving tire performance. Some would upgrade existing tests, while the others would add new ones."

In an official release, the Department of Transportation (DOT) said "the new standard would substantially upgrade the existing high speed and endurance tests for new tires. It also proposes new test procedures to assess the likelihood of tire failure from striking a road hazard, like a pothole, and from the tire bead coming off the vehicle wheel during hard driving maneuvers.

"The proposal also adds tests in two new areas. The first new test is to ensure that tires will not fail when underinflated.

"The second new test would assess the tire's performance after the tire has been aged. The

proposal sets forth some alternatives for the new tests for low inflation performance and for aged tire performance.

"The new standard also proposes to establish the same performance requirements for car and light truck tires. It also proposes to require that the load of cars and light trucks with three adult passengers cannot be more than 85% of the load-carrying capacity of the tires on the vehicle at the inflation pressure recommended by the vehicle manufacturer, instead of the 88% currently required.

"This proposal is designed to ensure that there will be an adequate reserve of load-carrying capacity in the tires.

"While the agency believes that its proposed amendments would improve tire safety and are based on the best currently available information, it is concerned about the potential costs of these amendments.

"NHTSA expects to receive data and other information in the public comments that will enable it to refine its assessment of benefits and costs. The agency will then be in a better position to choose among the proposed amendments.

"Section 10 of the TREAD Act requires the agency to issue a final rule on this tire upgrade by June 1, 2002. To meet this statutory deadline, the agency has limited its tire upgrade research and analysis to conventional tires for light vehicles.

"Congress did not set a deadline by which all applicable tires would be required to meet the upgraded standard."

The agency is proposing the two alternative implementation schedules:

* a two-year phase-in whereby all applicable tires must comply with the final rule by Sept. 1, 2004, and

* a three-year phase-in whereby all applicable tires must comply with the final rule by Sept. 1, 2005.

Comments will be accepted for 60 days from the date of publication in the Federal Register, according to the DOT. Comments in writing should be sent to: Docket Management, Room PL-401, 400 Seventh Street, SW., Washington, D.C., 20590.

Comments also can be submitted electronically by logging onto the Docket Management System Web site at Click on "Help & Information" or "Help/Info" to view instructions for filing.

All comments should mention Docket No. NHTSA-00-8011.

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