2010 Mercedes GLK-Class Owner's Manual - Page 236

234 Tires and wheels The safe speed on a wet, snow covered or icy road is always lower than on a dry road. You should pay particular attention to the condition of the road whenever the outside temperature is close to the freezing point. Mercedes-Benz recommends winter tires (Y page 241) with a minimum tread depth of approximately 1/6 in (4 mm) on all four wheels for the winter season to ensure normal balanced handling characteristics. On packed snow, they can reduce your stopping distance compared to summer tires. Stopping distance, however, is still considerably greater than when the road is not covered with snow or ice. Exercise appropriate caution. laboratory test wheel than the minimum required by law. Rotating tires G Warning! Rotate front and rear wheels only if the tires are of the same dimension. If your vehicle is equipped with mixed-size tires (different tire dimensions front vs. rear), tire rotation is not possible. Operation G Warning! ! Avoid spinning of a drive wheel. This may cause serious damage to the drivetrain which is not covered by the Mercedes-Benz Limited Warranty. 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. Have the tightening torque checked after changing a wheel. The wheels could come loose if they are not tightened to a torque of 110 lb-ft (150 Nm). Only use genuine Mercedes-Benz wheel bolts specified for your vehicle's rims. The temperature grades are A (the highest), B, and C, representing 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, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on the Tire rotation can be performed on vehicles with tires of the same dimension all around. If your vehicle is equipped with tires of the same dimension all around, tires can be rotated, observing a front-to-rear rotation pattern that will maintain the intended rotation (spinning) direction of the tire (Y page 231). In some cases, such as when your vehicle is equipped with mixed-size tires (different tire dimension front vs. rear), tire rotation is not possible. If applicable to your vehicle's tire configuration, tires can be rotated according to the tire manufacturer's recommended intervals in the tire manufacturer's warranty pamphlet located in your vehicle literature portfolio. If none is available, tires should be rotated every 3 000 to 6 000 miles (5 000 to 10 000 km), or sooner if necessary, according to the degree of tire wear. The same rotation (spinning) direction must be maintained. Rotate tires before the characteristic tire wear pattern becomes visible (shoulder wear on front tires and tread center wear on rear tires).