NHTSA issues final rule on tire testing

June 23, 2003

All manufacturers who build tires for light vehicles must comply with the National Highway Traffic Safety Administration's newly finalized tire testing standards within four years.

The National Highway Traffic Safety Administration (NHTSA) issued its final tire testing rule earlier today.

It "establishes new and more stringent tire performance requirements that apply to all radial tires for use on passenger cars, multi-purpose passenger vehicles, trucks, buses an trailers that have a gross vehicle weight rating of 10,000 pounds or less" and have been manufactured after 1975, according to NHTSA officials.

The rule also applies to new cars, multi-purpose passenger vehicles, trucks, buses and trailers under 10,000 pounds.

NHTSA has made changes and/or adjustments in the following categories:

1. High speed and endurance. Tires will now be evaluated at over 50% more distance than the current tests call for;

2. Low inflation pressure performance. NHTSA is adopting a low inflation pressure test that will "ensure a minimum level of inflation at which tire pressure monitoring systems will be required to be activated." It is designed to replicate the conditions of long-distance travel;

3. Applicability. For the first time ever, NHTSA is requiring that light trucks have a specified tire reserve. The agency also is "extending the tire performance requirements for passenger cars tires to LT tires (load ranges C, D, and E) used on light trucks."

However, NHTSA is retaining old road hazard impact and bead unseating standards for the time being but will continue to evaluate them.

The agency also has declined to implement tests to measure the deterioration of tire performance due to aging, but "is commencing its own research" on the process and will probably propose an aging test within two years.

NHTSA is giving tire and vehicle producers a four-year lead-in time in light of the "extent and significance of design and production changes that might have to be made as a result of changing requirements in an area that has not been substantively revised in 30 years," say agency officials.

To read the full report, click on: http://www.nhtsa.dot.gov/cars/rules/rulings/UpgradeTire/Final/Index.html