7-25
INSPECTION AND MAINTENANCE
79K21-03E
Tires
For safe operation of your vehicle, it is
important that the tires be the correct
type and size, in good condition, and
properly inflated. Be sure to follow the
requirements and recommendations in
this section.
Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The example
below shows a typical passenger car
tire.
Typical Passenger Car Tire Sidewall
67D027
A. Tire Manufacturer
The name of the tire manufacturer
is shown here.
B. Tire Name/Model
The tire name or model is shown
here.
C. Tire Size
The tire size code is a combina-
tion of letters and numbers used
to define a particular tire’s width,
height, aspect ratio, construction
type, and service description. See
the “Tire Size” explanation later in
this section for more details.
D. U.S. DOT Tire Identification Num-
ber
The Department of Transportation
(DOT) marking indicates that the
tire is in compliance with the U.S.
Department of Transportation
Motor Vehicle Safety Standards.
The letters and numbers following
the DOT marking is the Tire Iden-
tification Number (TIN). The TIN
identifies the tire manufacturer
and plant, tire size, and date the
tire was manufactured.
E. Uniform Tire Quality Grading
(UTQG)
Tire manufacturers are required to
grade tires based on three perfor-
mance factors: treadwear, traction
and temperature resistance.
Refer to the “Uniform Tire Quality
Grading” section for more details.
F. Load Rating
Load rating is the maximum
weight a tire is designed to sup-
port in normal service.
G. Max Inflation Pressure
Max inflation pressure is the max-
imum inflation pressure a tire is
designed for.
H. Tire Ply Material
These tire markings describe the
type of cord and number of plies
in the sidewall and under the
tread.
I. Load Index and Speed Rating
The two- or three-digit number is
the tire’s load index, the maximum
load a tire can carry at the speed
indicated by its speed symbol at
the maximum inflation pressure.
The higher the number is, the
greater the load carrying capacity.
The letter symbol denotes the
speed at which a tire is designed
to be driven for extended periods
of time. (Ratings are listed below.)
A
H
B
G
E
F
D
J
I
C
EXAMPLE
Tires: 6
English 
