Cadillac 2010 STS Owner's Manual

Also see for 2010 STS: Brochure Owner's manual

(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, asshown in item C of the illustration, it would meanthat the tire's sidewall is 60 percent as high as itis 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; theletter D means diagonal or bias ply construction;and the letter B means belted‐bias plyconstruction.(E) Rim Diameter : Diameter of the wheel ininches.(F) Service Description : These charactersrepresent the load index and speed rating of thetire. The load index represents the load carrycapacity a tire is certified to carry. The speedrating is the maximum speed a tire is certified tocarry a load.Tire Terminology and DefinitionsAir Pressure : The amount of air inside the tirepressing outward on each square inch of the tire.Air pressure is expressed in pounds per squareinch (psi) or kilopascal (kPa).Accessory Weight : This means the combinedweight of optional accessories. Some examples ofoptional accessories are, automatic transmission,power steering, power brakes, power windows,power seats, and air conditioning.Aspect Ratio : The relationship of a tire's heightto its width.Belt : A rubber coated layer of cords that islocated between the plies and the tread. Cordsmay be made from steel or other reinforcingmaterials.Bead : The tire bead contains steel wireswrapped by steel cords that hold the tire ontothe rim.Bias Ply Tire : A pneumatic tire in which the pliesare laid at alternate angles less than 90 degreesto the centerline of the tread.6-57