2011 Mercedes C-Class Owner's Manual - Page 287

Uniform Tire Quality Grading Standards Where applicable, the tire grading information can be found on the tire sidewall between the tread shoulder and maximum tire width. For example: Tread wear Traction 200 AA Temperature A 285 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. All passenger car tires must conform to the statutory safety requirements in addition to these grades. Tread wear The tread wear 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 track. For example, a tire graded 150 would wear one and one-half times as well on the government test track 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 conditions. ! Avoid wheelspin. This can lead to damage to the drive train. Temperature G Warning The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause excessive heat build-up and possible tire failure. Traction G Warning 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. The traction grades, from highest to lowest, are AA, A, B, and C. These grades represent the tire's ability to stop on a wet surface as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance. The temperature grades are A (the highest), B, and C. These represent the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life. Furthermore, excessive temperature can lead to sudden tire failure. Grade C corresponds to a level of performance that all passenger Z Tires and wheels The safe speed on a wet, snow covered or icy road is always lower than on dry road surfaces. You should pay special attention to road conditions when temperatures are around the freezing point. Mercedes-Benz recommends a minimum tire tread depth of 1/6 in (4 mm) for all four winter tires (Y page 154) to maintain normal driving characteristics in winter. Winter tires can reduce the braking distance on snow covered surfaces in comparison to summer tires. The braking distance is still much further than on surfaces that are not icy or covered with snow. Take appropriate care when driving.