3938-1. Specifications
8
Vehicle specifications
would wear one and a half (1 - 1/2)
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. Performance may differ
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 high-
est to lowest, are AA, A, B and
C, and they represent the tire’s
ability to stop on wet pavement
as measured under controlled
conditions on specified govern-
ment 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
braking (straight ahead) traction
tests and does not include corner-
ing (turning) traction.
■Temperature A, B, C
The temperature grades are A (the highest), B, and C, repre-
senting 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 labo-
ratory 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.
Grade C corresponds to a level of
performance which all passenger
car tires must meet under the Fed-
eral Motor Vehicle Safety Standard
No. 109.
Grades B and A represent higher
levels of performance on the labo-
ratory test wheel than the minimum
required by law.
Warning: The temperature grades
of a tire assume tha t it is properly
inflated and not overloaded.
Excessive speed, underinflation, or
excessive loading, either sepa-
rately or in combination, can cause
heat buildup and possible tire fail-
ure.
Glossary of tire terminology
Tire related termMeaning
Cold tire infl ation pressure
Tire pressure when the vehicle has been
parked for three hours or more, or has not
been driven more than 1 mile or 1.5 km
under that condition
Maximum inflation pressure
The maximum cold inf lated pressure to
which a tire may be inflated, shown on the
sidewall of the tire
