Treadwear
The treadwear grade is a comparative
rating based on the wear rate of the tire
when tested under controlled conditions
on a specified government test course.
For example, a tire graded 150 would
wear one and one-half (1 ½) 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 AA A B C
WARNING
The traction grade assigned to this
tire is based on straight-ahead
braking traction tests, and does not
include acceleration, cornering,
hydroplaning or peak traction
characteristics.
The traction grades, from highest to
lowest are AA, A, B, and C. The 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
performance.
Temperature A B C
WARNING
The temperature grade for this tire
is established for a tire that is
properly inflated and not overloaded.
Excessive speed, underinflation, or
excessive loading, either separately or
in combination, can cause heat buildup
and possible tire failure.
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 Vehicle Safety Standard
No. 139. Grades B and A represent
higher levels of performance on the
laboratory test wheel than the minimum
required by law.
Glossary of Tire Terminology
*Tire label: A label showing the original
equipment tire sizes, recommended
inflation pressure and the maximum
weight the vehicle can carry.
*Tire Identification Number (TIN): A
number on the sidewall of each tire
providing information about the tire
brand and manufacturing plant, tire size
and date of manufacture. Also referred
to as DOT code.
*Inflation pressure: A measure of the
amount of air in a tire.
299
Navigator (TB5) Canada/United States of America, enUSA, First Printing
Wheels and Tires
