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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.
