2010 Mercedes GL-Class Owner's Manual - Page 250

248 Tires and wheels recommended minimum tire tread depth for winter tires is 1/6 in (4 mm). regarding tire performance. Tire manufacturers are required to grade tires based on three performance factors: treadwear :, traction ;, and temperature resistance =. Although not a Government of Canada requirement, all tires made for sale in North America have these grades branded on the sidewall. Treadwear indicator : appears as a solid band across the tread. Storing tires ! Keep unmounted tires in a cool, dry place with as little exposure to light as possible. Protect tires from contact with oil, grease and fuels. Cleaning tires ! Never use a round nozzle to power wash tires. The intense jet of water can result in damage to the tire. Always replace a damaged tire. Uniform Tire Quality Grading Standards i For illustration purposes only. Actual data on tires are specific to each vehicle and may vary from data shown in above illustration. Quality grades can be found, where applicable, on the tire sidewall between tread shoulder and maximum section width. For example: Treadwear 200 Traction AA Temperature A Operation All passenger car tires must conform to federal safety requirements in addition to these grades. Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified U.S. Government test course. For example, a tire graded 150 would wear one and one-half (1 1/2) times as well on the government course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate. Traction G Warning! The Uniform Tire Quality Grading is a U.S. Government requirement designed to give drivers consistent and reliable information The traction grade assigned to this tire is based on straight-ahead braking traction