service SUBARU IMPREZA 2006 2.G Manual PDF

13-12 Consumer information and Reporting safety defects
Uniform tire quality grading
standards
This information indicates the relative
performance of passenger car tires in
the area of treadwear, traction, and
temperature resistance. This is to aid
the consumer in making an informed
choice in the purchase of tires.
Quality grades can be found where
applicable on the tire sidewall be-
tween tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Tem-
perature A
The quality grades apply to new pneu-
matic tires for use on passenger cars.
However, they do not apply to deep
tread, winter type snow tires, space-
saver or temporary use spare tires,
tires with nominal rim diameters of 12
inches or less, or to some limited pro-
duction tires.
All passenger car tires must confirm
to Federal Safety Requirements in
addition to these grades.
Treadwear
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 example, 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 perfor-
mance of tires depends upon the ac-
tual conditions of their use, however,
and may depart significantly from the
norm due to variations in driving hab-
its, 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 speci-
fied government test surfaces of as-
phalt and concrete. A tire marked C
may have poor traction performance.
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 condi-
tions on a specified indoor laboratory
test wheel. Sustained high tempera-
ture 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 corre-
sponds to a level of performance
which all passenger car tires must
meet under the Federal Motor Vehicle
Safety Standards No. 109. Grades B
and A represent higher levels of per-
formance on the laboratory test wheel
than the minimum required by law.
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 characteristics.