Cadillac SRX Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-9087647) - 2016 - crc - 5/4/15282 Vehicle Careinformation on tire pressure andinflation see Tire Pressure0 285.(6) Tire Size : A combination ofletters and numbers define atire's width, height, aspect ratio,construction type, and servicedescription. The letter T as thefirst character in the tire sizemeans the tire is for temporaryuse only.(7) TPC Spec (TirePerformance CriteriaSpecification) : Originalequipment tires designed toGM's specific tire performancecriteria have a TPC specificationcode molded onto the sidewall.GM's TPC specifications meet orexceed all federal safetyguidelines.Tire DesignationsTire SizeThe following is an example of atypical passenger vehicletire size.(1) Passenger (P-Metric) Tire :The United States version of ametric tire sizing system. Theletter P as the first character inthe tire size means a passengervehicle tire engineered tostandards set by the U.S. Tireand Rim Association.(2) Tire Width : The three-digitnumber indicates the tire sectionwidth in millimeters fromsidewall to sidewall.(3) Aspect Ratio : A two-digitnumber that indicates the tireheight-to-width measurements.For example, if the tire sizeaspect ratio is 60, as shown initem 3 of the illustration, it wouldmean that the tire's sidewall is60 percent as high as it is wide.(4) Construction Code : A lettercode is used to indicate the typeof ply construction in the tire.The letter R means radial plyconstruction; the letter D meansdiagonal or bias plyconstruction; and the letter Bmeans belted-bias plyconstruction.(5) Rim Diameter : Diameter ofthe wheel in inches.(6) Service Description : Thesecharacters represent the loadindex and speed rating of thetire. The load index representsthe load carrying capacity a tireis certified to carry. The speedrating is the maximum speed atire is certified to carry a load.
