Maintenance
54
7
7. Uniform tire quality grading
Quality grades can be found where
applicable on the tire sidewall
between tread shoulder and maxi-
mum chapter width.
For example:
TREADWEAR 200
TRACTION AA
TEMPERATURE A
Tread wear
The tread wear grade is a compara-
tive rating based on the wear rate ofthe tire when tested under controlled
conditions on a specified govern-
ment test course. For example, a tire
graded 150 would wear one-and-a-
half times (1½) as well on the gov-
ernment 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 because
of variations in driving habits, service
practices and differences in road
characteristics and climate. These grades are molded on the
side-walls of passenger vehicle tires.
The tires available as standard or
optional equipment on your vehicles
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 tires ability to
stop on wet pavement as measuredunder controlled conditions on speci-
fied government test surfaces of
asphalt and concrete. A tire marked C
may have poor traction performance.
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. Grades B and A
represent higher levels of perform-
ance on the laboratory test wheel
than the minimum required by the law.
WARNING
The traction grade assigned to this tire is based on straight-ahead braking traction tests,
and does not include accelera-
tion, cornering, hydroplaning,
or peak traction characteristics.WARNING - Tire temperature
The temperature grade for this
tire is established for a tire that is
properly inflated and not over-
loaded. Excessive speed, under-
inflation, or excessive loading,
either separately or in combina-
tion, can cause heat build-up and
possible sudden tire failure. This
can cause loss of vehicle control
and serious injury or death.
JD PE eng 7.QXP 1/28/2016 5:37 PM Page 54
