2009 Mercedes E-Class Owner's Manual - Page 269

Operation Tires and wheels Uniform Tire Quality Grading Standards 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. 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 1 Maximum permissible tire inflation pressure i For illustration purposes only. Actual data on tires are specific to each vehicle and may vary from data shown in above illustration. This is the maximum permissible tire inflation pressure for the tire. Always follow the recommended tire inflation pressure (Y page 253) for proper tire inflation. 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, 1 Treadwear 2 Traction 3 Temperature resistance Z 267