GMC 2011 Acadia - Manual (Page 386)

Black plate (58,1) GMC Acadia/Acadia Denali Owner Manual - 2011
10-58 Vehicle Care
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 specified 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 acceleration, cornering,
hydroplaning, or peak traction
characteristics.
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
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 Safety
Standard No. 109. Grades B
and A represent higher levels of
performance 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 excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.