2006 Mercedes E-Class Owner's Manual - Page 346

Operation Tires and wheels General: Depending on the design standards used, the tire size molded into the sidewall may have no letter or a letter preceding the tire size designation. No letter preceding the size designation (as illustrated above): Passenger car tire based on European design standards. Letter "P" preceding the size designation: Passenger car tire based on U.S. design standards. Letter "LT" preceding the size designation: Light Truck tire based on U.S. design standards. Letter "T" preceding the size designation: Temporary spare tires which are high pressure compact spares designed for temporary emergency use only. Tire width The tire width 1 ( page 344) indicates the nominal tire width in mm. Aspect ratio The aspect ratio 2 ( page 344) 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 344) 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 346). Rim diameter The rim diameter 4 ( page 344) 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 344) 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 350) where the maximum load associated with the load index is indicated in kilograms and lbs. 345