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INFORMATION ON PASSENGER VEHICLE TIRES
Please refer to the diagram below.
P
The “P” indicates the tire is for passenger vehicles.
NEXT NUMBER
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
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
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
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 that the tire has some mud and
snow capability. Most radial tires have these markings; hence,
they have some mud and snow capability.
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.
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
This 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 it was manufactured, 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
This number indicates the maximum load in kilograms and
pounds that can be carried by the tire.
