2006 Mercedes R-Class Owner's Manual - Page 378
2006 Mercedes R-Class Manual
Page 378 highlights
Operation Tires and wheels Aspect ratio The aspect ratio 2 ( page 376) is the dimensional relationship between tire section height and section width and is expressed in percentage. The aspect ratio is arrived at by dividing section height by section width. Tire code The tire code 3 ( page 376) indicates the tire construction type. The "R" stands for radial tire type. Letter "D" means diagonal or bias ply construction; letter "B" means belted-bias ply construction. At the tire manufacturer's option, any tire with a speed capability above 149 mph (240 km/h) can include a "ZR" in the size designation (for example: 245/40 ZR 18). For additional information, see "Tire speed rating" ( page 378). Rim diameter The rim diameter 4 ( page 376) is the diameter of the bead seat, not the diameter of the rim edge. Rim diameter is indicated in inches (in). Tire load rating The tire load rating 5 ( page 376) is a numerical code associated with the maximum load a tire can support. For example, a load rating of 91 corresponds to a maximum load of 1356 lbs (615 kg) the tire is designed to support. See also "Maximum tire load" ( page 382) where the maximum load associated with the load index is indicated in kilograms and lbs. Warning! G The tire load rating must always be at least half of the GAWR ( page 386) of your vehicle. Otherwise, tire failure may be the result which may cause an accident and/or serious personal injury to you or others. Always replace rims and tires with the same designation, manufacturer and type as shown on the original part. Warning! G Do not overload the tires by exceeding the specified load limit as indicated on the placard located 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. 377