Honda Civic Sedan 1993 Owner's Manual page 146

Tires
Traction
The traction grades, from highest
to lowest, are A, B, and C, and they
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 as-
signed to this tire is based on brak-
ing (straight ahead) traction tests
and does not include cornering
(turning) traction.
Maintenance
Temperature
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 Vehicle
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 build-up and
possible tire failure.