Subaru 2008 IMPREZA - Manual (Page 369)

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 government
course as a tire graded 100. The
relative performance of tires de-
pends 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 perfor-
mance.
WARNING
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests,
and does not include accel-
eration, cornering, hydroplan-
ing, or peak traction charac-
teristics.
& 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 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 perfor-
mance on the laboratory test wheel
than the minimum 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 ex-
cessive loading, either sepa-
rately or in combination, can
cause heat buildup and possi-
ble tire failure.
Consumer information and Reporting safety defects
13-13