Consumer information and Reporting safety defects/Uniform tire quality grading standards
All passenger car tires must con-
form to Federal Safety Require-
ments in addition to these grades.
& Treadwear
The treadwear grade is a compara-
tive rating based on the wear rate of
the tire when tested under con-
trolled conditions on a specified
government test course.
For example, a tire graded 150
would wear one and one-half (1-
1/2) times as well on the govern-
ment 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
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 spe-
cified government test surfaces of
asphalt and concrete.
A tire marked C may have poor
traction performance.
WARNING
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests,
and does not include accelera-
tion, cornering, hydroplaning,
or peak traction characteris-
tics.
& Temperature A, B, C
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 con-
ditions on a specified indoor labora-
tory test wheel.
Sustained high temperature can
cause the material of the tire to
degenerate and reduce tire life, and
13-15
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 Stan-
dards No. 109.
Grades B and A represent higher
levels of performance on the la-
boratory test wheel than the mini-
mum required by law.
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.