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.
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).
NOTE
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.
* 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
T: 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:
Information on Temporary Tires
Please refer to the sample below.
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.
WARNING
Do not stack cargo or objects higher than the seatbacks:
Cargo stacked higher than the seatbacks is dangerous. It can block your view in the rearview mirror, which might cause you to hit another car when changing lanes.
Rearview mirror adjustment
Before driving, adjust the rearview mirror to center on the scene through the rear window.