318 VEHICLE CAREPassenger (P-Metric) Tire Example(1) Tire Size : The tire size is acombination of letters andnumbers used to define aparticular tire's width, height,aspect ratio, construction type,and service description. See the“Tire Size” illustration later in thissection.(2) TPC Spec (Tire PerformanceCriteria Specification) : Originalequipment tires designed to GM'sspecific tire performance criteriahave a TPC specification codemolded onto the sidewall. GM'sTPC specifications meet or exceedall federal safety guidelines.(3) DOT (Department ofTransportation) : TheDepartment of Transportation(DOT) code indicates that the tireis in compliance with the U.S.Department of TransportationMotor Vehicle Safety Standards.DOT Tire Date of Manufacture :The last four digits of the TINindicate the tire manufactureddate. The first two digits representthe week (01–52) and the last twodigits, the year. For example, thethird week of the year 2010 wouldhave a four-digit DOT dateof 0310.(4) Tire Identification Number(TIN) : The letters and numbersfollowing the DOT (Department ofTransportation) code are the TireIdentification Number (TIN). TheTIN shows the manufacturer andplant code, tire size, and date thetire was manufactured. The TIN ismolded onto both sides of the tire,although only one side may havethe date of manufacture.(5) Tire Ply Material : The typeof cord and number of plies in thesidewall and under the tread.(6) Uniform Tire QualityGrading (UTQG) : Tiremanufacturers are required tograde tires based on threeperformance factors: treadwear,traction, and temperatureresistance. For more informationsee Uniform Tire Quality Grading0 333.(7) Maximum Cold InflationLoad Limit : Maximum load thatcan be carried and the maximumpressure needed to supportthat load.
