SECTION 4 - SERVICE AND MAINTENANCE
4-18
– Triple-L-Trailer –
3121224
Information on Trailer Tires
S
ID
EW
AL
L 2
P
LI
ES
•
2X
X
X
X
X
C
O
R
D
•
M
A
X
L
O
A
D
X
X
X
k
g
X
XX
LB
S
• M
AX
PRESS XX PSI • R
AD
IAL
•
T
U
B
E
L
E
S
S
•
P
LY
R
A
T
IN
G
•
T
R
E
A
D
X
P
LIE
S•
LO
AD
R
AN
GE
•
Figure 4-12. Tire Information
1.
Tire Application
- This letter identifies the tire by
application.
• LT = Light Trucks or Trailers
• ST = Trailer use only
2.
Tire Width
-
This three-digit number gives the width
in millimeters of the tire from sidewall edge to side-
wall edge. In general, the larger the number, the
wider the tire.
3.
Aspect Ratio -
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 han-
dling on dry pavement.
4.
Radial -
The "R" stands for radial. Radial ply con-
struction of tires has been the industry standard for
the past 20 years.
5.
Wheel Diameter -
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.
6.
Maximum Load Rating -
This number indicates the
maximum load in kilograms and pounds that can
be carried by the tire.
7.
Maximum Permissible Inflation Pressure -
This
number is the greatest amount of air pressure that
shall ever be put in the tire under normal driving
conditions.
8.
Ply Rating -
The term "Ply Rating" is used to identify
a given tire with its maximum load when used in a
specific type of service. It is an index of tire strength
and does not necessarily represent the number of
cord plies in the tire.
9.
Load Range
- A letter (A,B,C etc.) used to identify a
given size tire with its load and inflation limits when
used in a specific type of service.
10.
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.
