Tire Information (U.S.A.)
Information on Passenger Vehicle Tires
Please refer to the sample below.
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SAFETY WARNING
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Passenger car tire
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Nominal width of tire in millimeters
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Ratio of height to width (aspect ratio)
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Radial
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Run-flat tire
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Rim diameter code
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TIN: U.S. DOT tire identification number
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Load index & speed symbol
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Severe snow conditions
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Tire ply composition and materials used
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Max. load rating
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Tread wear, traction and temperature grades
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Max. permissible inflation pressure
P215/65R15 95H is an example of a tire size and load index rating. Here is an explanation of the various components of that tire size and load index rating. Note that the tire size and load index rating may be different from the example.
P
Indicates a tire that may be installed on cars, SUVs, minivans and light trucks as designated by the Tire and Rim Association (T&RA).
If your tire size does not begin with a letter this may mean it is designated by either ETRTO (European Tire and Rim Technical Organization) or JATMA (Japan Tire Manufacturing Association).
215
“215” is the nominal width of the tire in millimeters. This three-digit number gives the width in millimeters of the tire from sidewall edge to sidewall edge. In general, the larger the number, the wider the tire.
65
“65” is the aspect ratio. This two-digit number indicates the tire's ratio of height to width.
R
“R” is the tire construction symbol. R indicates “Radial ply construction”.
15
“15” is the wheel rim diameter in inches.
95
“95” is the Load Index. This two-or three-digit number indicates how much weight each tire can support.
H
“H” is the speed rating. The speed rating denotes the maximum speed for which the use of the tire is rated.
|
Letter Rating |
Speed Rating |
|---|---|
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Q |
99 mph |
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R |
106 mph |
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S |
112 mph |
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T |
118 mph |
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U |
124 mph |
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H |
130 mph |
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V |
149 mph |
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W |
168* mph |
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Y |
186* mph |
* For tires with a maximum speed capability over 149 mph, tire manufacturers sometimes use the letters ZR. For tires with a maximum speed capability over 186 mph, tire manufacturers always use the letters ZR.
M+S or M/S: Mud and Snow
AT: All Terrain.
AS: All Season. The “M+S” or “M/S” indicates that the tire has some functional use in mud and snow.
U.S. DOT Tire Identification Number (TIN)
This begins with the letters “DOT” which indicates the tire meets all federal standards. The next two numbers or letters are the plant code where it was manufactured, and the last four numbers represent the week and year the tire was manufactured. For example, the numbers 457 means the 45st week of 1997. After 2000 the numbers go to four digits. For example, the number 2102 means the 21th week of 2002. The other numbers are marketing codes used at the manufacturer's discretion. This information is used to contact consumers if a tire defect requires a recall.
Tire Ply Composition and Materials Used
The number of plies indicates the number of layers of rubber-coated fabric in the tire. In general, the greater the number of plies, the more weight a tire can support. Tire manufacturers also must indicate the tire materials, which include steel, nylon, polyester, and other.
Maximum Load Rating
This number indicates the maximum load in kilograms and pounds that can be carried by the tire.
Maximum Permissible Inflation Pressure
This number is the greatest amount of air pressure that should ever be put in the tire under normal driving conditions.
Tread Wear, Traction and Temperature Grades
Tread wear: The tread wear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one-half (1 1/2) times as well on the government course as a tire graded 100.
Traction: The traction grades, from highest to lowest are AA, A, B, and C. The grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance.
Temperature: The temperature grades are A (the highest), B and C, representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel.
Snow Tires
In some heavy snow areas, local governments may require true snow tires, those with very deeply cut tread. These tires should only be used in pairs or placed on all four wheels. Make sure you purchase snow tires that are the same size and construction type as the other tires on your vehicle.
SAFETY WARNING
The following safety warning appears on the tire's sidewall.
SERIOUS INJURY MAY RESULT FROM:
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EXPLOSION OF TIRE/RIM ASSEMBLY DUE TO IMPROPER MOUNTING-MATCH TIRE DIAMETER TO RIM DIAMETER; NEVER EXCEED 40 psi (275 kPa) TO SEAT BEADS-ONLY SPECIALLY TRAINED PERSONS SHOULD MOUNT TIRES.
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TIRE FAILURE DUE TO UNDER-INFLATION/OVERLOADING/DAMAGE-FOLLOW OWNER'S MANUAL AND PLACARD IN VEHICLE-FREQUENTLY CHECK INFLATION PRESSURE AND INSPECT FOR DAMAGE.
Information on Temporary Tires
Please refer to the sample below.
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Temporary tires
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Nominal width of tire in millimeters
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Ratio of height to width (aspect ratio)
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Diagonal
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Rim diameter code
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Load index & speed symbol
T115/70D16 90M is an example of a tire size and load index rating. Here is an explanation of the various components of that tire size and load index rating. Note that the tire size and load index rating may be different from the example.
T
Indicates a tire that may be installed on cars, SUVs, minivans and light trucks as designated by the Tire and Rim Association (T&RA).
115
“115” is the nominal width of the tire in millimeters. This three-digit number gives the width in millimeters of the tire from sidewall edge to sidewall edge. In general, the larger the number, the wider the tire.
70
“70” is the aspect ratio. This two-digit number indicates the tire's ratio of height to width.
D
“D” is the tire construction symbol. D indicates “diagonal ply construction”.
16
“16” is the wheel rim diameter in inches.
90
“90” is the Load Index. This two-or three-digit number indicates how much weight each tire can support.
M
“M” is the speed rating. The speed rating denotes the maximum speed for which the use of the tire is rated.
|
Letter Rating |
Speed Rating |
|---|---|
|
M |
81 mph |
Checking Tire Pressure
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When you check the air pressure, make sure the tires are cold ―meaning they are not hot from driving even a mile.
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Remove the cap from the valve on one tire.
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Firmly press a tire gauge onto the valve.
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Add air to achieve recommended air pressure.
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If you overfill the tire, release air by pushing on the metal stem in the center of the valve. Then recheck the pressure with your tire gauge.
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Replace the valve cap.
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Repeat with each tire, including the spare.
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Visually inspect the tires to make sure there are no nails or other objects embedded that could poke a hole in the tire and cause an air leak.
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Check the sidewalls to make sure there are no gouges, cuts, bulges, cracks or other irregularities.
Glossary of Terms
Tire Placard: A label indicating the OE tire sizes, recommended inflation pressure, and the maximum weight the vehicle can carry.
Tire Identification Number (TIN): A number on the sidewall of each tire providing information about the tire brand and manufacturing plant, tire size, and date of manufacture.
Inflation Pressure: A measure of the amount of air in a tire.
kPa: Kilopascal, the metric unit for air pressure.
psi: Pounds per square inch, the English unit for air pressure.
B-pillar: The structural member at the side of the vehicle behind the front door.
Original Equipment (OE): Describes components originally equipped on the vehicle.
Vehicle Load Limit: The maximum value of the combination weight of occupants and cargo.
Bead Area of the Tire: Area of the tire next to the rim.
Sidewall Area of the Tire: Area between the bead area and the tread.
Tread Area of the Tire: Area on the perimeter of the tire that contacts the road when it's mounted on the vehicle.
Seating capacity means the total allowable number of vehicle occupants. Seating capacity is described on the tire label.
Production options weight is the combination weight of installed regular production options weighing over 2.3 kilograms in excess of the standard items which they replace, and not previously considered in the curb weight or accessory weight, including heavy duty brakes, ride levelers, roof rack, heavy duty battery, and special trim.
Rim is the metal support (wheel) for a tire or a tire and tube assembly upon which the tire beads are seated.
Tire Maintenance
Improper or inadequate vehicle maintenance can cause tires to wear abnormally. Here are some important maintenance points:
Replacing a Tire
Always use tires that are in good condition.
Driving with worn tires is dangerous. Reduced braking, steering, and traction could result in an accident.
If a tire wears evenly, a wear indicator will appear as a solid band across the tread.
Replace the tire when this happens.
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New tread
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Worn tread
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Tread wear indicator
You should replace the tire before the band crosses the entire tread.
Tires degrade over time, even when they are not being used on the road. It is recommended that tires generally be replaced when they are 6 years or older. Heat caused by hot climates or frequent high loading conditions can accelerate the aging process. You should replace the spare tire when you replace the other road tires due to the aging of the spare tire. The period in which the tire was manufactured (both week and year) is indicated by a 4-digit number.
Refer to Tire Labeling (Search).
Safety Practices
The way you drive has a great deal to do with your tire mileage and safety. So cultivate good driving habits for your own benefit.
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Observe posted speed limits and drive at speeds that are safe for the existing weather conditions
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Avoid fast starts, stops and turns
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Avoid potholes and objects on the road
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Do not run over curbs or hit the tire against the curb when parking
If you feel a sudden vibration or ride disturbance while driving or you suspect your tire or vehicle has been damaged, immediately reduce your speed. Drive with caution until you can safely pull off the road. Stop and inspect the tire for damage. If the tire is under-inflated or damaged, deflate it, remove the tire and rim and replace it with your spare tire. If you cannot detect a cause, have the vehicle towed to the nearest vehicle or tire dealer to have the vehicle inspected.
Vehicle Loading
Do not tow a trailer with this vehicle.
Towing a trailer with this vehicle is dangerous because it has not been designed to tow a trailer and doing so will affect the drive system which could result in vehicle damage.
This section will guide you in the proper loading of your vehicle, to keep your loaded vehicle weight within its design rating capability. Properly loading your vehicle will provide maximum return of vehicle design performance. Before loading your vehicle, familiarize yourself with the following terms for determining your vehicle's weight ratings, from the vehicle's Safety Certification Label and Tire and Load Information Label:
Overloaded Vehicle.
Overloading a vehicle is dangerous. The results of overloading can have serious consequences in terms of passenger safety. Too much weight on a vehicle's suspension system can cause spring or shock absorber failure, brake failure, handling or steering problems, irregular tire wear, tire failure or other damage.
Overloading makes a vehicle harder to drive and control. It also increases the distance required for stopping. In cases of serious overloading, brakes can fail completely, particularly on steep grades. The load a tire will carry safely is a combination of the size of the tire, its load range, and corresponding inflation pressure.
Never overload the vehicle and always observe the vehicle's weight ratings from the vehicle's Safety Certification and Tire and Load Information labels.
Base Curb Weight is the weight of the vehicle including a full tank of fuel and all standard equipment. It does not include passengers, cargo, or optional equipment.
Vehicle Curb Weight is the weight of your new vehicle when you picked it up from your dealer plus any aftermarket equipment.
PAYLOAD
Payload is the combination weight of cargo and passengers that the vehicle is designed to carry. The maximum payload for your vehicle can be found on the Tire and Load Information label on the driver's door frame or door pillar. Look for “THE COMBINATION WEIGHT OF OCCUPANTS AND CARGO SHOULD NEVER EXCEED XXX kg or XXX lbs” for your maximum payload. The payload listed on the tire label is the maximum payload for the vehicle as built by the assembly plant. If any aftermarket or dealer installed equipment has been installed on the vehicle, the weight of the equipment must be subtracted from the payload listed on the tire label in order to be accurate.
SAMPLE
CARGO
Cargo Weight includes all weight added to the Base Curb Weight, including cargo and optional equipment.
The cargo weight limit decreases depending on the number of vehicle occupants. The cargo weight limit can be calculated by subtracting the total weight of the vehicle occupants from the “combination weight of occupants and cargo should never exceed” value on the tire label.
Examples: Based on a single occupant weight of 68 kg (150 lbs), and a value of 385 kg (849 lbs) for the “combination weight of occupants and cargo should never exceed”:
The cargo weight limit with one occupant is 385 kg (849 lbs) － 68 kg (150 lbs) = 317 kg (699 lbs)
The cargo weight limit with two occupants is 385 kg (849 lbs) － (68 × 2) kg ( (150 × 2) lbs) = 249 kg (549 lbs)
If the weight of the occupant increases, the cargo weight limit decreases by that much.
GAW (Gross Axle Weight) is the total weight placed on each axle (front and rear) - including vehicle curb weight and all payload.
GAWR (Gross Axle Weight Rating) is the maximum allowable weight that can be carried by a single axle (front or rear). These numbers are shown on the Safety Compliance Certification Label located on the driver's door frame or door pillar. The total load on each axle must never exceed its GAWR.
GVW
GVW (Gross Vehicle Weight) is the Vehicle Curb Weight + cargo + passengers.
GVWR (Gross Vehicle Weight Rating) is the maximum allowable weight of the fully loaded vehicle (including all options, equipment, passengers and cargo). The GVWR is shown on the Safety Compliance Certification Label located on the driver's door frame or door pillar. The GVW must never exceed the GVWR.
SAMPLE
Never Exceed Axle Weight Rating Limits.
Exceeding the Safety Certification Label axle weight rating limits is dangerous and could result in death or serious injury as a result of substandard vehicle handling, performance, engine, transmission and/or structural damage, serious damage to the vehicle, or loss of control.
Always keep the vehicle within the axle weight rating limits.
GCW
GCW (Gross Combination Weight) is the weight of the loaded vehicle (GVW).
GCWR (Gross Combination Weight Rating) is the maximum allowable weight of the vehicle - including all cargo and passengers - that the vehicle can handle without risking damage. The GCW must never exceed the GCWR.
Never Exceed GVWR or GAWR Specifications.
Exceeding the GVWR or the GAWR specified on the certification label is dangerous. Exceeding any vehicle rating limitation could result in a serious accident, injury, or damage to the vehicle.
Do not use replacement tires with lower load carrying capacities than the originals because they may lower the vehicle's GVWR and GAWR limitations. Replacement tires with a higher limit than the originals do not increase the GVWR and GAWR limitations.
Never exceed the GVWR or the GAWR specified on the certification label.
