the material of the tire to degenerateand reduce tire life, and excessivetemperature can lead to sudden tirefailure. The grade C corresponds to alevel of performance which allpassenger car tires must meet under theFederal Motor Vehicle Safety StandardNo. 139. Grades B and A representhigher levels of performance on thelaboratory test wheel than the minimumrequired by law.
Glossary of Tire Terminology
*Tire label: A label showing the originalequipment tire sizes, recommendedinflation pressure and the maximumweight the vehicle can carry.
*Tire Identification Number (TIN): A
number on the sidewall of each tireproviding information about the tirebrand and manufacturing plant, tire sizeand date of manufacture. Also referredto as DOT code.
*Inflation pressure: A measure of theamount of air in a tire.
*Standard load: A class of P-metric orMetric tires designed to carry amaximum load at set pressure. Forexample: For P-metric tires 35 psi(2.4 bar) and for Metric tires 36 psi(2.5 bar). Increasing the inflationpressure beyond this pressure will notincrease the tire’s load carryingcapability.
*Extra load: A class of P-metric or Metrictires designed to carry a heaviermaximum load at 42 psi (2.9 bar).Increasing the inflation pressure beyondthis pressure will not increase the tire’sload carrying capability.
*kPa: Kilopascal, a metric unit of airpressure.
*PSI: Pounds per square inch, a standard
unit of air pressure.
*Cold tire pressure: The tire pressurewhen the vehicle has been stationaryand out of direct sunlight for an hour ormore and prior to the vehicle beingdriven for 1 mi (1.6 km).
*Recommended inflation pressure: Thecold inflation pressure found on theSafety Compliance Certification Label(affixed to either the door hinge pillar,door-latch post, or the door edge thatmeets the door-latch post, next to thedriver's seating position), or Tire Labellocated on the B-Pillar or the edge of thedriver door.
* B-pillar: The structural member at theside of the vehicle behind the front door.
*Bead area of the tire: Area of the tirenext to the rim.
* Sidewall of the tire: Area between thebead area and the tread.
*Tread area of the tire: Area of theperimeter of the tire that contacts the
road when mounted on the vehicle.
*Rim: The metal support (wheel) for atire or a tire and tube assembly uponwhich the tire beads are seated.
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Information Contained on the TireSidewall
Both United States and Canada Federalregulations require tire manufacturersto place standardized information on thesidewall of all tires. This informationidentifies and describes the fundamentalcharacteristics of the tire and alsoprovides a U.S. DOT Tire IdentificationNumber for safety standard certificationand in case of a recall.
Information on P Type Tires
P215/65R15 95H is an example of a tiresize, load index and speed rating. Thedefinitions of these items are listedbelow. (Note that the tire size, load indexand speed rating for your vehicle maybe different from this example.)
A. P: Indicates a tire, designated by theTire and Rim Association, that may beused for service on cars, sport utilityvehicles, minivans and light trucks. Note:If your tire size does not begin with aletter this may mean it is designated byeither the European Tire and RimTechnical Organization or the Japan TireManufacturing Association.
B. 215: Indicates the nominal width ofthe tire in millimeters from sidewall edgeto sidewall edge. In general, the largerthe number, the wider the tire.
C. 65: Indicates the aspect ratio whichgives the tire's ratio of height to width.
D. R: Indicates a radial type tire.
E. 15: Indicates the wheel or rim
diameter in inches. If you change yourwheel size, you will have to purchasenew tires to match the new wheeldiameter.
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F. 95: Indicates the tire's load index. Itis an index that relates to how muchweight a tire can carry. You may find thisinformation in your owner’s manual. Ifnot, contact a local tire dealer.
Note:You may not find this informationon all tires because it is not required byfederal law.
G. H: Indicates the tire's speed rating.The speed rating denotes the speed atwhich a tire is designed to be driven forextended periods of time under astandard condition of load and inflationpressure. The tires on your vehicle mayoperate at different conditions for loadand inflation pressure. These speedratings may need to be adjusted for thedifference in conditions. The ratings
range from 81 mph (130 km/h) to186 mph (299 km/h). These ratings arelisted in the following chart.
Note:You may not find this informationon all tires because it is not required byfederal law.
Speed ratingLetter rating
81 mph (130 km/h)M
87 mph (140 km/h)N
99 mph (159 km/h)Q
106 mph (171 km/h)R
112 mph (180 km/h)S
118 mph (190 km/h)T
124 mph (200 km/h)U
130 mph (210 km/h)H
149 mph (240 km/h)V
Speed ratingLetter rating
168 mph (270 km/h)W
186 mph (299 km/h)Y
Note:For tires with a maximum speed
capability over 149 mph (240 km/h), tire
manufacturers sometimes use the letters
ZR. For those with a maximum speed
capability over 186 mph (299 km/h), tire
manufacturers always use the letters
ZR.
H. U.S. DOT Tire Identification Number(TIN): This begins with the letters DOTand indicates that the tire meets allfederal standards. The next twonumbers or letters are the plant codedesignating where it was manufactured,
the next two are the tire size code andthe last four numbers represent theweek and year the tire was built. Forexample, the numbers 317 mean the 31stweek of 1997. After 2000, the numbers
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go to four digits. For example, 2501means the 25th week of 2001. Thenumbers in between are identificationcodes used for traceability. Thisinformation is used to contact customersif a tire defect requires a recall.
I. M+S or M/S: Mud and Snow, or
AT: All Terrain, or
AS: All Season.
J. Tire Ply Composition and MaterialUsed: Indicates the number of plies orthe number of layers of rubber-coatedfabric in the tire tread and sidewall. Tiremanufacturers also must indicate the plymaterials in the tire and the sidewall,which include steel, nylon, polyester,and others.
K. Maximum Load: Indicates themaximum load in kilograms and poundsthat can be carried by the tire. See theSafety Compliance Certification Label(affixed to either the door hinge pillar,door-latch post, or the door edge thatmeets the door-latch post, next to thedriver's seating position), for the correcttire pressure for your vehicle.
L. Treadwear, Traction andTemperature Grades:
*Treadwear The treadwear grade is acomparative rating based on the wearrate of the tire when tested undercontrolled conditions on a specifiedgovernment test course. For example,a tire graded 150 would wear one andone-half times as well on the
government course as a tire graded 100.
*Traction: The traction grades, fromhighest to lowest are AA, A, B, and C.The grades represent the tire's ability tostop on wet pavement as measuredunder controlled conditions on specifiedgovernment test surfaces of asphalt andconcrete. A tire marked C may havepoor traction performance.
*Temperature: The temperature gradesare A (the highest), B and C,representing the tire's resistance to thegeneration of heat and its ability todissipate heat when tested undercontrolled conditions on a specifiedindoor laboratory test wheel.
M. Maximum Inflation Pressure:Indicates the tire manufacturers'maximum permissible pressure or the
pressure at which the maximum loadcan be carried by the tire. This pressureis normally higher than the vehiclemanufacturer's recommended coldinflation pressure which can be foundon the Safety Compliance CertificationLabel (affixed to either the door hingepillar, door-latch post, or the door edgethat meets the door-latch post, next to
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the driver's seating position), or TireLabel which is located on the B-Pillar orthe edge of the driver’s door. The coldinflation pressure should never be setlower than the recommended pressureon the vehicle label.
The tire suppliers may have additionalmarkings, notes or warnings such asstandard load or radial tubeless.
Additional Information Contained onthe Tire Sidewall for LT Type Tires
Note:Tire Quality Grades do not applyto this type of tire.
LT type tires have some additional
information beyond those of P type tires;these differences are described below.
A. LT: Indicates a tire, designated by theTire and Rim Association, that isintended for service on light trucks.
B. Load Range and Load InflationLimits: Indicates the tire's load-carryingcapabilities and its inflation limits.
C. Maximum Load Dual lb (kg) at psi(kPa) cold: Indicates the maximum loadand tire pressure when the tire is usedas a dual, defined as four tires on therear axle (a total of six or more tires onthe vehicle).
D. Maximum Load Single lb (kg) at psi(kPa) cold: Indicates the maximum loadand tire pressure when the tire is usedas a single, defined as two tires (total)on the rear axle.
Information on T Type Tires
T145/80D16 is an example of a tire size.
Note:The temporary tire size for yourvehicle may be different from thisexample. Tire Quality Grades do notapply to this type of tire.
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T type tires have some additionalinformation beyond those of P type tires;these differences are described below:
A. T: Indicates a type of tire, designatedby the Tire and Rim Association, that isintended for temporary service on cars,sport utility vehicles, minivans and lighttrucks.
B. 145: Indicates the nominal width ofthe tire in millimeters from sidewall edgeto sidewall edge. In general, the largerthe number, the wider the tire.
C. 80: Indicates the aspect ratio whichgives the tire's ratio of height to width.Numbers of 70 or lower indicate a shortsidewall.
D. D: Indicates a diagonal type tire.
R: Indicates a radial type tire.
E. 16: Indicates the wheel or rimdiameter in inches. If you change your
wheel size, you will have to purchasenew tires to match the new wheeldiameter.
Recommended Tire Pressures andInflating Your Tires
Safe operation of your vehicle requiresthat your tires are properly inflated.Remember that a tire can lose up to halfof its air pressure without appearing flat.Every day before you drive, check yourtires. If one looks lower than the others,use a tire gauge to check the pressureof all tires and adjust if required.
At least once a month and before longtrips, inspect each tire and check the tirepressure with a tire gauge (includingspare, if equipped). Inflate all tires to theinflation pressure recommended by FordMotor Company.
WARNING: Under-inflation is themost common cause of tire failuresand may result in severe tire cracking,tread separation or blowout, withunexpected loss of vehicle control andincreased risk of injury. Under-inflationincreases sidewall flexing and rolling
resistance, resulting in heat buildup
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and internal damage to the tire. It alsomay result in unnecessary tire stress,irregular wear, loss of vehicle controland accidents. A tire can lose up tohalf of its air pressure and not appearto be flat!
You are strongly urged to buy a reliabletire pressure gauge, as automaticservice station gauges may beinaccurate. Ford recommends the useof a digital or dial-type tire pressuregauge rather than a stick-type tirepressure gauge. Use the recommendedcold inflation pressure for optimum tireperformance and wear. Under-inflationor over-inflation may cause uneventreadwear patterns.
Always inflate your tires to the Fordrecommended inflation pressure evenif it is less than the maximum inflationpressure information found on the tire.You will find a Tire Label containing theFord recommended tire inflationpressure by the tire size and otherimportant information located on theB-Pillar or the edge of the driver’s door.
The Ford recommended tire inflationpressure is also found on the SafetyCompliance Certification Label (affixedto either the door hinge pillar, door-latchpost, or the door edge that meets thedoor-latch on the B-pillar, or on the edgeof the driver’s door.
Failure to follow the tire pressurerecommendations can cause uneventreadwear patterns and adversely affectthe way your vehicle handles.
Inspecting Your Tires and Wheel ValveStems
Periodically inspect the tire treads foruneven or excessive wear and removeobjects such as stones, nails or glassthat may be wedged in the tread
grooves. Check the tire and valve stemsfor holes, cracks, or cuts that may permitair leakage and repair or replace the tireand replace the valve stem. Inspect thetire sidewalls for cracking, cuts, bruisesand other signs of damage or excessivewear. If internal damage to the tire is
suspected, have the tire demounted andinspected in case it needs to be repairedor replaced. For your safety, tires thatare damaged or show signs of excessivewear should not be used because theyare more likely to blow out or fail.
Improper or inadequate vehiclemaintenance can cause tires to wearabnormally. Inspect all your tires,including the spare, frequently, andreplace them if one or more of thefollowing conditions exist:
Tire Wear
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When the tread is worn down to onesixteenth of an inch (2 mm), tires mustbe replaced to help prevent your vehiclefrom skidding and hydroplaning. Built-intreadwear indicators, or wear bars,which look like narrow strips of smoothrubber across the tread will appear onthe tire when the tread is worn down toone sixteenth of an inch (2 mm).
When the tire tread wears down to thesame height as these wear bars, the tireis worn out and must be replaced.
Damage
Periodically inspect the tire treads andsidewalls for damage (such as bulges inthe tread or sidewalls, cracks in thetread groove and separation in the tread
or sidewall). If damage is observed orsuspected, have the tire inspected by atire professional. Tires can be damagedduring off-road use, so inspection afteroff-road use is also recommended.
Age
WARNING: Tires degrade overtime depending on many factors suchas weather, storage conditions, andconditions of use (load, speed, inflationpressure) the tires experiencethroughout their lives.In general, tires should be replacedafter six years regardless of treadwear. However, heat caused by hotclimates or frequent high loadingconditions can accelerate the agingprocess and may require tires to bereplaced more frequently.You should replace your spare tirewhen you replace the road tires orafter six years due to aging even if ithas not been used.
U.S. DOT Tire Identification Number
Both United States and Canada Federalregulations require tire manufacturersto place standardized information on thesidewall of all tires. This informationidentifies and describes the fundamentalcharacteristics of the tire and alsoprovides a U.S. DOT Tire IdentificationNumber for safety standard certificationand in case of a recall.
This begins with the letters DOT andindicates that the tire meets all federalstandards. The next two numbers orletters are the plant code designatingwhere it was manufactured, the next twoare the tire size code and the last fournumbers represent the week and yearthe tire was built. For example, the
numbers 317 mean the 31st week of1997. After 2000, the numbers go to fourdigits. For example, 2501 means the25th week of 2001. The numbers inbetween are identification codes usedfor traceability. This information is usedto contact customers if a tire defectrequires a recall.
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