P
- The “P” indicates the tire is for passenger vehicles.
NOTE: Passenger car tires are not recommended for use on trailers, because the capacity ratings are not marked on the side walls of
these tires. In the event a passenger car tire is used, the capacity must be derated by 10%.
Next number (Positions 2, 3 & 4)
- 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.
Next number (Positions 5 & 6)
- This two-digit number, known as the aspect ratio, gives the tire’s ratio of height to width. Numbers of
70 or lower indicate a short sidewall for improved steering response and better overall handling on dry pavement.
R -
The “R” stands for radial. Radial ply construction of tires has been the industry standard for the past 20 years.
Next number (Positions 8 & 9) -
This two-digit number is the wheel or rim diameter in inches. If you change your wheel size, you will
have to purchase new tires to match the new wheel diameter.
Next number (Position 10, 11 and/or 12) -
This two- or three-digit number is the tire’s load index. It is a measurement of how much
weight each tire can support. You may find this information in your owner’s manual. If not, contact a local tire dealer. Note: You may not
find this information on all tires because it is not required by law.
M+S -
The “M+S” or “M/S” indicates the tire has some mud/snow capability. Most radial tires have these markings.
Speed Rating -
The speed rating denotes the speed at which a tire is designed to be driven for extended periods of time. The ratings
range from 99 miles per hour (mph) to 186 mph. These ratings are listed below. Note: You may not find this information on all tires
because it is not required by law
Letter Rating Speed Rating
Q
99 mph
R
106 mph
S
112 mph
T
118 mph
U
124 mph
H
130 mph
V
149 mph
W
168* mph
Y
186* mph
* For tires with a maximum speed capability over 149 mph, tire manufacturers sometimes use the letters ZR. For those with a maximum
speed capability over 186 mph, tire manufacturers always use the letters ZR.
U.S. DOT Tire Identification Number -
Begins with the letters “DOT” and indicates that the tire meets all federal standards. The next
two numbers or letters are the plant code where of manufacture, and the last four numbers represent the week and year the tire was built.
For example, the numbers 3197 means the 31st week of 1997. 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 materials in the tire,
which include steel, nylon, polyester, and others.
Maximum Load Rating -
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.
Information on Passenger Vehicle Tires
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