2010 Mercedes C-Class Owner's Manual - Page 246

244 Tires and wheels 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 Treadwear 200 Traction AA Temperature A 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. Operation Traction G Warning! The Uniform Tire Quality Grading is a U.S. Government requirement designed to give drivers consistent and reliable information 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. The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics. 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: The traction grades, from highest to lowest, are AA, A, B, and C. Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance. G Warning! If ice has formed on the road, tire traction will be substantially reduced. Under such weather conditions, drive, steer and brake with extreme caution.