7-32
Maintenance
Temperature - A, B & C
The temperature grades are A (the highest), B and C representing the
tire’s resistance to the generation ofheat and its ability to dissipate heatwhen tested under controlled condi-
tions on a specified indoor laboratorytest 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
responds 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 labora-
tory test wheel than the minimum
required by law.
Tire Terminology and Definitions
Air Pressure
The amount of air inside the tire
pressing outward on the tire.
Air pressure is expressed in kilopas-
cal (kPa) or pounds per square inch(psi).
Accessory Weight
This means the combined weight of
optional accessories. Some exam-
ples of optional accessories are
automatic transmission, power
seats, and air conditioning.
Aspect Ratio
The relationship of a tire's height toits width.
Belt
A rubber coated layer of cords that is
located between the plies and the
tread. Cords may be made from steel
or other reinforcing materials.
The temperature grade for this
tire is established for a tire that
is properly inflated and not
overloaded. Excessive speed,
under-inflation, over-inflation,
or excessive loading, either
separately or in combination,
can cause heat build-up and
possible sudden tire failure.
This may cause loss of vehicle
control resulting in an accident.
WARNING
