2009 Mercedes E-Class Owner's Manual - Page 250

Operation Tires and wheels Tire care and maintenance G Warning! Regularly check the tires for damage. Damaged tires can cause tire inflation pressure loss. As a result, you could lose control of your vehicle. Worn, old tires can cause accidents. If the tire tread is worn to minimum tread depth, or if the tires have sustained damage, replace them. Check the tire inflation pressure at least every other week. For more information on checking tire inflation pressure, see "Recommended tire inflation pressure" (Y page 253). Replace the tire if you find any of the above conditions. Make sure you also inspect the spare tire periodically for condition and inflation. Spare tires will age and become worn over time even if never used, and thus should be inspected and replaced when necessary. (1.6 mm), we recommend that you do not allow your tires to wear down to that level. As tread depth approaches 1/8 in (3 mm), the adhesion properties on a wet road are sharply reduced. Depending upon the weather and/or road surface (conditions), the tire traction varies widely. Do not allow your tires to wear down too far. Adhesion properties on wet roads are sharply reduced at tread depths of less than 1/8 in (3 mm). Treadwear indicators (TWI) are required by law. These indicators are located in six places on the tread circumference and become visible at a tread depth of approximately 1/ in (1.6 mm), at which point the tire is 16 considered worn and should be replaced. The recommended minimum tire tread depth for summer tires is 1/8 in (3 mm). The recommended minimum tire tread depth for winter tires is 1/6 in (4 mm). Life of tire G Warning! Tires and spare tire should be replaced after 6 years, regardless of the remaining tread. The service life of a tire is dependent upon varying factors including but not limited to: RDriving RTire Tire inspection Every time you check the tire inflation pressure, you should also inspect your tires for the following: Rexcessive Rcord style driven inflation pressure RDistance treadwear (Y page 248) Tread depth G Warning! Although the applicable federal motor vehicle safety laws consider a tire to be worn when the treadwear indicators (TWI) become visible at approximately 1/16 in or fabric showing through the tire's rubber bulges, cuts, cracks or splits in the tread or side of the tire Rbumps, 248