FORD 1998 Explorer - Manual (Page 178)

grade 100. The relative performance of tires depends 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 A B C
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
test surfaces of asphalt and concrete. A tire marked C may have poor
traction performance.
The traction grade assigned to this tire is based on braking
(straight ahead) traction tests and does not include cornering
(turning) traction.
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 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.
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.
SERVICING YOUR TIRES
Checking the tire pressure
• Use an accurate tire pressure gauge.
• Check the tire pressure when tires are cold, after the vehicle has been
parked for at least one hour or has been driven less than 5 km (3
miles).
Maintenance and care
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