Transport i bezpieczeństwo · 5.06.1998

Consumer Information Regulations: Uniform Tire Quality Grading Standards

This notice of proposed rulemaking (NPRM) proposes to amend the treadwear testing procedures under the Uniform Tire Quality Grading Standards (UTQGS). To ensure the consistency of the treadwear grades from one year to the next, the agency must monitor the changing roughness of the test course, periodically calculate a base course wear rate (BCWR), and adjust measured tire wear rates accordingly. To monitor the test course, the agency uses special tires designated as course monitoring tires (CMTs). The agency is proposing to change the computation of the BCWR used in calculating the treadwear grade of passenger car tires. Under the proposed amendments, there would be a direct comparison of the wear rates of course monitoring tires (CMT) used as the control standard and candidate tires, i.e, the tires being tested for the purposes of grading. This direct comparison would result in more consistent treadwear ratings by compensating for any changes or variations in CMT characteristics. NHTSA proposes to measure the wear rate of CMTs 4 times per year and using the average wear rate from the last 4 quarterly CMT tests as a basis for the BCWR. NHTSA further proposes to require, subject to