Tire Information (U.S.A.)
Tire Labeling
Tire Labeling
Federal law requires tire manufacturers to place standardized information on the sidewall of all tires. This information identifies and describes the fundamental characteristics of the tire and also provides a tire identification number for safety standard certification and in case of a recall.
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 |
|---|---|
|
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 |
Recommended Tire Inflation Pressure
On the tire label you will find the recommended tire inflation pressure in both kPa and psi for the tires installed as original equipment on the vehicle. It is very important that the inflation pressure of the tires on your vehicle is maintained at the recommended pressure. You should check the tire pressure regularly to insure that the proper inflation pressure is maintained.
Refer to Tires (Search).
Tire pressures listed on the vehicle placard or tire information label indicate the recommended cold tire inflation pressure, measured when the tires are cold, after the vehicle has been parked for at least 3 hours. As you drive, the temperature in the tire warms up, increasing the tire pressure.
Always check the tire inflation pressures on a regular basis according to the recommended tire inflation pressure on the tire label and in conjunction with the information in this owner's manual:
Driving your vehicle with under-inflated tires is dangerous.
Under-inflation is the most common cause of failures in any kind of tire and may result in severe cracking, tread separation or “blowout”, with unexpected loss of vehicle control and increased risk of injury. Under-inflation increases sidewall flexing and rolling resistance, resulting in heat buildup and internal damage to the tire. It results in unnecessary tire stress, irregular wear, loss of control and accidents. A tire can lose up to half of its air pressure and not appear to be flat!
It is impossible to determine whether or not tires are properly inflated just by looking at them.
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.
