Maintenance
9-40
8. Uniform tyre quality grading
Quality grades can be found where
applicable on the tyre sidewall between
tread shoulder and maximum section
width.
For example:
TREADWEAR 200
TRACTION AA
TEMPERATURE A
Tread wear
The tread wear grade is a comparative
rating based on the wear rate of the tyre
when tested under controlled conditions
on a specified government test course.
For example, a tyre graded 150 would
wear one-and-a-half times (1½) as well
on the government course as a tyre
graded 100.
The relative performance of tyres
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 tyres. The
tyres 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 tyre’s ability to stop on wet
pavement as measured under controlled
conditions on specified government
test surfaces of asphalt and concrete. A
tyre marked C may have poor traction
performance.
WARNING
The traction grade assigned to this
tyre 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 tyre’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 tyre to degenerate
and reduce tyre life, and excessive
temperature can lead to sudden tyre
failure. Grades B and A represent higher
levels of performance on the laboratory
test wheel than the minimum required
by law.
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