2006 Mercedes S-Class Owner's Manual - Page 300

Operation Tires and wheels Tread depth Do not allow your tires to wear down too far. Adhesion properties on wet roads are sharply reduced at tread depths under 1/ in (3 mm). 8 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 1/16 in (1.6 mm), at which point the tire is considered worn and should be replaced. Recommended minimum tire tread depth: Summer tires 1/8 in (3 mm) Winter tires 1/6 in (4 mm) Warning! Storing 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. ! Keep unmounted tires in a cool, dry place with as little exposure to light as possible. Protect tires from contact with oil, grease and gasoline. Cleaning tires ! Never use a round nozzle to power wash tires. The intense jet of water can result in damage to the tire. Always replace a damaged tire. G 1 TWI (TreadWear Indicator) The treadwear indicator appears as a solid band across the tread. Although the applicable federal motor safety laws consider a tire to be worn when the treadwear indicators (TWI) become visible at approximately 1/16 in (1.6 mm), we recommend that you do not allow your tires 299