Loading ...
Loading ...
Loading ...
EXAMPLE : DOT MA L9 ABCD 1504
DOT Department of Transportation
This symbol certifies that the tire is in compli-
ance with U.S. Department of Transportation tire
safety standards, and is approved for highway
use.
MA Code representing the tire manufacturing loca-
tion. (2 digits)
L9
ABCD
Code representing the tire size. (2 digits)
Code used by tire manufacturer. (1 to 4 digits)
15 Number representing the week in which the tire
was manufactured. (2 digits)
04 Number representing the year in which the tire
was manufactured. (2 digits)
Treadwear, Traction and Temperature Grades
Traction
The treadwear grade is a comparative rating based on the
wear rate of the tire when tested under controlled con-
ditions on a specified government test course. For ex-
ample, a tire graded 150 would wear one and one half
(1 1/2) times as well on the government course as a tire
graded 100. The relative performance of tires depends
upon the actual conditions of their use, however, and
may depart significantly from the norm due to variations
in driving habits, service practices and differences in road
characteristics and climate.
Traction
The traction grades, from highest to lowest, are AA, A, B
and C. Those grades represent the tire’s ability to stop on
wet pavement as measured under controlled conditions
on specified government test surfaces of asphalt and
concrete. A tire marked C may have poor traction perfor-
mance.
Temperature
The temperature grades are A (the highest), B and C,
representing the tire’s resistance to the generation of heat
and its ability to dissipate heat when tested under
controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the
material of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire failure. The
grade C corresponds to a level of performance which all
passenger car tires must meet under the Federal Motor
MAINTENANCE 339
9
Loading ...
Loading ...
Loading ...