Page 12
Page 12
SECTION
2
Identification and Safety
M+S
‘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.
IMPORTANT NOTE:
IF IT BECOMES NECESSARY TO REPLACE A TIRE AND
YOU FEEL IT IS A WARRANTY ISSUE, MOST TIRE
MANUFACTUERS REQUIRE THE D.O.T. NUMBER BE CUT
OUT AND RETURNED TO THEM, WITH THE WARRANTY
CLAIM, OTHERWISE THE WARRANTY COULD BE
VOIDED.
U.S. DOT Tire Identification Number
This 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 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
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.
Speed Rating
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.
Note: This information may not appear on all tires since it is
not required by law.
Q
99 mph
H
130 mph
R
106 mph
V
149 mph
S
112 mph
W
168 mph*
T
118 mph
Y
186 mph*
U
124 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.
TIRE FUNDAMENTALS
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.
P
Indicates the tire is for passenger vehicles.
Next (3 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 (2 Digit) Number
Gives the tire’s ratio of height to width, (known as the aspect
ratio). Numbers of 70 or lower indicate a short sidewall for
improved steering response and better overall handling on
dry pavement.
R
‘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.
If you are unsure, contact a local tire dealer. Note: You may
not find this information on all tires since it is not required
by law.