wet pavement as measured under controlled conditions
on specified government tests surfaces of asphalt and
concrete. A tire marked C may have poor traction perfor-
mance.
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 repre-
sent higher levels of performance on the laboratory test
wheel than the minimum required by law.
Tire inflation pressures
Proper tire inflation pressure is essential to the safe and
satisfactory operation of your vehicle. Three primary
areas are affected by improper tire pressure:1. Safety
Under-inflation increases tire flexing and can result in tire
failure. Over-inflation results in a tire losing its ability to
cushion shock. Objects on the road and potholes could
cause tire damage that may result in tire failure.
2. Economy
Improper inflation pressures can cause uneven wear
patterns to develop across the tire tread. These abnormal
wear patterns will reduce tread life, resulting in a need
for earlier tire replacement.
Under-inflation also increases tire rolling resistance and
results in higher fuel consumption.
3. Ride comfort and vehicle stability
Proper tire inflation pressures contribute to the excellent
ride quality built into your vehicle. Over-inflation pro-
duces an uncomfortable and jarring ride.
Under-inflation can produce a feeling of sluggish re-
sponse.
Unequal inflation pressures can produce erratic and
unpredictable vehicle response to steering maneuvers.
The proper tire pressure for your vehicle is listed on a
placard attached near the door sill striker on the driver's
336 MAINTENANCE
