2011 Mercedes CL-Class Owner's Manual - Page 457

Tire labeling ratio is calculated by dividing the tire width by the tire height. Tire code: tire code = specifies the tire type. "R" represents radial tires. "D" represents diagonal tires, "B" represents diagonal radial tires. Optionally, tires with a maximum speed of over 149 mph (240 km/h) may have "ZR" in the size description depending on the manufacturer (e.g. 245/40 ZR 18). Rim diameter: rim diameter ? is the diameter of the bead seat, not the diameter of the rim flange. The rim diameter is specified in inches (in). Load bearing index: load bearing index A is a numerical code which specifies the maximum load-bearing capacity of a tire. For further information on the load bearing index, see load index (Y page 456). Speed index: speed index B specifies the approved maximum speed of the tire. 455 G Warning Even when permitted by law, never operate a vehicle at speeds greater than the maximum speed rating of the tires. Exceeding the maximum speed for which tires are rated can lead to sudden tire failure, causing loss of vehicle control and possibly resulting in an accident and/or serious personal injury and possible death, for you and for others. G Warning Regardless of the speed index always observe the speed limits. Drive carefully and adapt your driving style to the traffic conditions. Summer tires Index Q R S T H V W Y ZR...Y ZR...(..Y) ZR Speed rating up to 100 mph (160 km/h) up to 106 mph (170 km/h) up to 112 mph (180 km/h) up to 118 mph (190 km/h) up to 130 mph (210 km/h) up to 149 mph (240 km/h) up to 168 mph (270 km/h) up to 186 mph (300 km/h) up to 186 mph (300 km/h) above 186 mph (300 km/h) above 149 mph (240 km/h) G Warning Do not overload the tires by exceeding the specified load limit as indicated on the Tire and Loading Information placard on the driver's door B-pillar. Overloading the tires can overheat them, possibly causing a blowout. Overloading the tires can also result in handling or steering problems, or brake failure. Example: The load bearing index 91 is equivalent to a maximum load of 1356 lbs (615 kg) that the tire can carry. For further information on the maximum tire load in kilograms and pounds, see (Y page 452). ROptionally, tires with a maximum speed of over 149 mph (240 km/h) may have "ZR" in the size description depending on the manufacturer (e.g. 245/40 ZR 18). Z Tires and wheels The tire load rating must always be at least half of the GAWR of your vehicle. Otherwise, sudden tire failure may be the result which could cause an accident and/or serious injury to you or others. Always replace rims and tires with rims and tires having the same specifications (designation, manufacturer and type) as shown on the original part.