(F) Uniform Tire Quality Grading (UTQG):Tire manufacturers are required to gradetires based on three performance factors:treadwear, traction and temperature resistance.For more information see Uniform Tire QualityGrading on page 6-69.(G) Maximum Cold Inflation Load Limit:Maximum load that can be carried and themaximum pressure needed to support that load.Tire SizeThe following illustration shows an example of atypical passenger (p-metric) vehicle tire size.(A) Passenger (P-Metric) Tire: The UnitedStates version of a metric tire sizing system.The letter P as the first character in the tire sizemeans a passenger vehicle tire engineeredto standards set by the U. S. Tire and RimAssociation.(B) Tire Width: The three-digit number indicatesthe tire section width in millimeters from sidewallto sidewall.(C) Aspect Ratio: A two-digit number thatindicates the tire height-to-width measurements.For example, if the tire size aspect ratio is 60,as shown in item C of the illustration, it wouldmean that the tire’s sidewall is 60 percent as highas it is wide.(D) Construction Code: A letter code is used toindicate the type of ply construction in the tire.The letter R means radial ply construction;the letter D means diagonal or bias plyconstruction; and the letter B means belted-biasply construction.(E) Rim Diameter: Diameter of the wheel ininches.(F) Service Description: These charactersrepresent the load range and speed rating of thetire. The load index represents the load carrycapacity a tire is certified to carry. The load indexcan range from 1 to 279. The speed rating isthe maximum speed a tire is certified to carry aload. Speed ratings range from A to Z.6-55
