2007 Mercedes C-Class Owner's Manual - Page 303

Operation Tires and wheels Always follow the recommended tire inflation pressure ( page 289) for proper tire inflation. Warning! Uniform Tire Quality Grading Standards (U.S. vehicles) Tire manufacturers are required to grade tires based on three performance factors: treadwear, traction, and temperature resistance. Quality grades can be found, where applicable, on the tire sidewall between tread shoulder and maximum section width. For example: Treadwear Traction Temperature 200 AA A G Never exceed the max. tire inflation pressure. Follow recommended tire inflation pressures. Do not underinflate tires. Underinflated tires wear excessively and/or unevenly, adversely affect handling and fuel economy, and are more likely to fail from being overheated. Do not overinflate tires. Overinflated tires can adversely affect handling and ride comfort, wear unevenly, increase stopping distance, and result in sudden deflation (blowout) because they are more likely to become punctured or damaged by road debris, potholes etc. 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 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 1 Treadwear 2 Traction 3 Temperature resistance i For illustration purposes only. Actual data on tires is specific to each vehicle and may vary from data shown in above illustration. 302