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Tread wear
The tread wear grade is a
comparative rating based on the
wear rate of the tire when tested
under controlled conditions on a
specified government test course.
For example, a tire graded 150 would
wear one-and-a-half times (1½) as
well on the government course as a
tire graded 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.
These grades are molded on the
sidewalls of passenger vehicle tires.
The tires available as standard or
optional equipment on your vehicle
may vary with respect to grade.
Traction - AA, A, B & C
The traction grades, from highest to
lowest, are AA, A, B and C. Those
grades 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.
The traction grade assigned to this
tire is based on straight ahead
braking traction tests, and does not
include acceleration, cornering,
hydroplaning, or peak traction
characteristics.
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. 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, 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.
Tire terminology and
definitions
Air pressure
The amount of air inside the tire
pressing outward on the tire. Air
pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
0_IK_PE_en_US.book Page 45
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