2010 CADILLAC DTS tire pressure

(A) Tire Size:The tire size code is a combinationof letters and numbers used to define a particulartire’s width, height, aspect ratio, constructiontype and service description. See the “Tire Size”illustration later in this section for more detail.
(B) TPC Spec (Tire Performance CriteriaSpecification):Original equipment tires designedto GM’s specific tire performance criteria havea TPC specification code molded onto the sidewall.GM’s TPC specifications meet or exceed allfederal safety guidelines.
(C) Dual Tire Maximum Load:Maximum loadthat can be carried and the maximum pressureneeded to support that load when used in a dualconfiguration.
(D) DOT (Department of Transportation):TheDepartment of Transportation (DOT) codeindicates that the tire is in compliance with theU.S. Department of Transportation Motor VehicleSafety Standards.
(E) Tire Identification Number (TIN):The lettersand numbers following DOT code are the TireIdentification Number (TIN). The TIN showsthe manufacturer and plant code, tire size, anddate the tire was manufactured. The TIN is moldedonto both sides of the tire, although only oneside may have the date of manufacture.
Light Truck Tire Example
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(F) Tire Ply Material:The type of cord andnumber of plies in the sidewall and underthe tread.
(G) Single Tire Maximum Load:Maximum loadthat can be carried and the maximum pressureneeded to support that load when used as asingle. For information on recommendedtire pressure seeInflation - Tire Pressure onpage 6-54.
Tire Size
The following illustration shows an example of atire size.
(A) P-Metric Tire:The United States version of ametric tire sizing system. The letter P as thefirst character in the tire size means a passengervehicle tire engineered to standards set by theU. S. Tire and Rim Association.
(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 is60, as shown in item C of the illustration, it wouldmean that the tire’s sidewall is 60 percent ashigh as 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 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.
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Tire Terminology and Definitions
Air Pressure:The amount of air inside thetire pressing outward on each square inch of thetire. Air pressure is expressed in pounds persquare inch (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 is locatedbetween the plies and the tread. Cords may bemade from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrappedby steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the pliesare laid at alternate angles less than 90 degreesto the centerline of the tread.
Cold Tire Pressure:The amount of air pressure ina tire, measured in pounds per square inch (psi) orkilopascals (kPa) before a tire has built up heatfrom driving. SeeInflation - Tire Pressure onpage 6-54.
Curb Weight:The weight of a motor vehicle withstandard and optional equipment including themaximum capacity of fuel, oil, and coolant,but without passengers and cargo.
DOT Markings:A code molded into the sidewallof a tire signifying that the tire is in compliancewith the U.S. Department of Transportation (DOT)motor vehicle safety standards. The DOT codeincludes the Tire Identification Number (TIN),an alphanumeric designator which can also identifythe tire manufacturer, production plant, brand,and date of production.
GVWR:Gross Vehicle Weight Rating. SeeLoading the Vehicle on page 5-18.
GAWR FRT:Gross Axle Weight Rating for thefront axle. SeeLoading the Vehicle on page 5-18.
GAWR RR:Gross Axle Weight Rating for therear axle. SeeLoading the Vehicle on page 5-18.
Intended Outboard Sidewall:The side of anasymmetrical tire, that must always face outwardwhen mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
Light Truck (LT-Metric) Tire:A tire used onlight duty trucks and some multipurpose passengervehicles.
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Load Index:An assigned number ranging from1 to 279 that corresponds to the load carryingcapacity of a tire.
Maximum Inflation Pressure:The maximum airpressure to which a cold tire can be inflated. Themaximum air pressure is molded onto the sidewall.
Maximum Load Rating:The load rating for a tireat the maximum permissible inflation pressurefor that tire.
Maximum Loaded Vehicle Weight:The sum ofcurb weight, accessory weight, vehicle capacityweight, and production options weight.
Normal Occupant Weight:The number ofoccupants a vehicle is designed to seat multipliedby 150 lbs (68 kg). SeeLoading the Vehicle onpage 5-18.
Occupant Distribution:Designated seatingpositions.
Outward Facing Sidewall:The side of anasymmetrical tire that has a particular side thatfaces outward when mounted on a vehicle. Theside of the tire that contains a whitewall, bearswhite lettering, or bears manufacturer, brand,and/or model name molding that is higher or deeperthan the same moldings on the other sidewall ofthe tire.
Passenger (P-Metric) Tire:A tire used onpassenger cars and some light duty trucks andmultipurpose vehicles.
Recommended Inflation Pressure:Vehiclemanufacturer’s recommended tire inflationpressure as shown on the tire placard. SeeInflation - Tire Pressure on page 6-54andLoadingthe Vehicle on page 5-18.
Radial Ply Tire:A pneumatic tire in which theply cords that extend to the beads are laid at90 degrees to the centerline of the tread.
Rim:A metal support for a tire and upon whichthe tire beads are seated.
Sidewall:The portion of a tire between the treadand the bead.
Speed Rating:An alphanumeric code assigned toa tire indicating the maximum speed at which atire can operate.
Traction:The friction between the tire and theroad surface. The amount of grip provided.
Tread:The portion of a tire that comes intocontact with the road.
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Treadwear Indicators:Narrow bands, sometimescalled wear bars, that show across the tread ofa tire when only 1/16 inch (1.6 mm) of treadremains. SeeWhen It Is Time for New Tires onpage 6-64.
UTQGS (Uniform Tire Quality GradingStandards):A tire information system thatprovides consumers with ratings for a tire’straction, temperature, and treadwear. Ratings aredetermined by tire manufacturers usinggovernment testing procedures. The ratings aremolded into the sidewall of the tire. SeeUniformTire Quality Grading on page 6-67.
Vehicle Capacity Weight:The number ofdesignated seating positions multiplied by 150 lbs(68 kg) plus the rated cargo load. SeeLoadingthe Vehicle on page 5-18.
Vehicle Maximum Load on the Tire:Load on anindividual tire due to curb weight, accessoryweight, occupant weight, and cargo weight.
Vehicle Placard:A label permanently attached toa vehicle showing the vehicle’s capacity weightand the original equipment tire size andrecommended inflation pressure. See “Tire andLoading Information Label” underLoadingthe Vehicle on page 5-18.
Inflation - Tire Pressure
Tires need the correct amount of air pressure tooperate effectively.
Notice:Do not let anyone tell you thatunder-inflation or over-inflation is all right. It isnot. If your tires do not have enough air(under-inflation), you can get the following:
•Too much flexing
•Too much heat
•Tire overloading
•Premature or irregular wear
•Poor handling
•Reduced fuel economy
If your tires have too much air (over-inflation),you can get the following:
•Unusual wear
•Poor handling
•Rough ride
•Needless damage from road hazards
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A Tire and Loading Information label is attached tothe vehicle’s center pillar. This label lists yourvehicle’s original equipment tires and shows thecorrect inflation pressures for your tires when theyare cold. The recommended cold tire inflationpressure, shown on the label, is the minimumamount of air pressure needed to supportyour vehicle’s maximum load carrying capacity.
For additional information regarding how muchweight your vehicle can carry, and an example ofthe Tire and Loading Information label, seeLoading the Vehicle on page 5-18. How you loadyour vehicle affects the vehicle handling andride comfort, never load your vehicle with moreweight than it was designed to carry.
When to Check
Check your tires once a month or more. Do notforget to check the spare tire. If your vehicle has acompact spare tire, it should be at 60 psi (420 kPa).For additional information seeSpare Tire onpage 6-90.
How to Check
Use a good quality pocket-type gage to check tirepressure. You cannot tell if your tires areproperly inflated simply by looking at them. Radialtires may look properly inflated even when theyare under-inflated. Check the tire’s inflationpressure when the tires are cold. Cold means yourvehicle has been sitting for at least three hoursor driven no more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem.Press the tire gage firmly onto the valve toget a pressure measurement. If the cold tireinflation pressure matches the recommendedpressure on the Tire and Loading Informationlabel, no further adjustment is necessary. If theinflation pressure is low, add air until you reach therecommended amount.
If you overfill the tire, release air by pushing onthe metal stem in the center of the tire valve.Re-check the tire pressure with the tire gage.
Be sure to put the valve caps back on the valvestems. They help prevent leaks by keeping out dirtand moisture.
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Professional Vehicle
The proper inflation of the tires on yourprofessional vehicle depends on the type of tireson it.
•If your vehicle has P235/60R17 size tires, the
cold inflation pressure is 41 psi (284 kPa).
•If your vehicle has LT235/60R17E size tires,
the cold inflation pressure depends on thevehicle mass and should be determined by thevehicle coach-builder. A Tire and LoadingInformation label provided by the final stagemanufacturer should be attached to the B-pillaron the driver’s side of the vehicle. If the finalstage manufacturer’s label is not present,the coach-builder should be consulted. Do notuse the tire pressures indicated on theGeneral Motors label. These tire pressures arefor the incomplete vehicle and are not thecorrect tire pressures for the completedprofessional vehicle.
Operation at inflation pressures below thisrecommendation may cause your tires to becomeoverloaded.
High-Speed Operation
{WARNING:
Driving at high speeds, 160 km/h (100 mph) or
higher, puts an additional strain on tires. Sustained
high-speed driving causes excessive heat build up
and can cause sudden tire failure. You could have
a crash and you or others could be killed. Some
high-speed rated tires require inflation pressure
adjustment for high speed operation. When speed
limits and road conditions are such that a vehicle
can be driven at high speeds, make sure the tires
are rated for high speed operation, in excellent
condition, and set to the correct cold tire inflation
pressure for the vehicle load.
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If your vehicle has P235/55R17 or P245/50R18 sizetires, and you will be driving at speeds of 100 mph(160 km/h) or higher, where it is legal, set the coldinflation pressure to the maximum inflation pressureshown on the tire sidewall, or 38 psi (265 kPa),whichever is lower. See the example following.
Example:
You will find the maximum load and inflation pressuremolded on the tire’s sidewall, in small letters, nearthe rim flange. It will read something like this: Maximumload 690 kg (1521 lbs) 300 kPa (44 psi) Max. Press.
For this example, you would set the inflation pressure forhigh-speed driving at 38 psi (265 kPa).
When you end this high-speed driving, return the tires tothe cold inflation pressure shown on the Tire andLoading Information label. SeeLoading the Vehicle onpage 5-18.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses radioand sensor technology to check tire pressure levels. TheTPMS sensors monitor the air pressure in yourvehicle’s tires and transmit tire pressure readings to areceiver located in the vehicle.
Each tire, including the spare (if provided), should bechecked monthly when cold and inflated to the inflationpressure recommended by the vehicle manufactureron the vehicle placard or tire inflation pressure label.(If your vehicle has tires of a different size than the sizeindicated on the vehicle placard or tire inflationpressure label, you should determine the proper tireinflation pressure for those tires.)
As an added safety feature, your vehicle has beenequipped with a tire pressure monitoring system (TPMS)that illuminates a low tire pressure telltale when oneor more of your tires is significantly under-inflated.
Accordingly, when the low tire pressure telltaleilluminates, you should stop and check your tires assoon as possible, and inflate them to the properpressure. Driving on a significantly under-inflated tirecauses the tire to overheat and can lead to tire failure.Under-inflation also reduces fuel efficiency and tiretread life, and may affect the vehicle’s handlingand stopping ability.
Please note that the TPMS is not a substitute for propertire maintenance, and it is the driver’s responsibility tomaintain correct tire pressure, even if under-inflation hasnot reached the level to trigger illumination of theTPMS low tire pressure telltale.
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