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Wheels
Uniform tire quality grading
- Tread
wear
-
Traction
AA A B C
-
Temperature
ABC
Quality grades can be found where applicable on
the tire side wall between tread shoulder and
maximum section width
c::>
page 205, fig. 167.
For
example: Tread
wear
200,
Traction
AA,
Tem-
perature
A.
All passenger car tires must conform to
Federal
Safety Requirements
in addition to these grades
.
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 gov
-
ernment
test
course.
For example, a tire graded 150 would wear one
and one half (11/2)
times
as well on the govern-
ment 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.
Traction
The
traction
grades, from highest to lowest, are
AA, A, Band C.
Those
grades represent the tire's
ability to stop on wet pavement as measured un-
der controlled
conditions
on specified govern-
ment test surfaces of asphalt and concrete. A
tire
marked C may have poor traction performance
¢
&..
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 mate-
rial of
the
tire to degenerate
and reduce tire life,
and excessive temperature
can
lead
to sudden
tire failure
c::>
.&.
.
222
The grade C corresponds to a
level
of perform-
ance which all passenger car tires must meet
un-
der the Federal
Motor
Veh icle Safety Standard
No.
109
.
Grades Band A represent higher levels
of performance on the laboratory test wheel than
the minimum
required
by law
.
A
WARNING
-
The traction grade assigned to this tire is
based on straight-ahead
braking traction
tests, and
does
not include acceleration,
cor-
nering, hydroplaning or peak
traction
charac-
teristics.
A
WARNING
,
~
-
The
temperature
grade
for
this tire is estab-
lished for a tire that
is
properly inflated and
not overloaded. Excessive speed,
underinfla-
tion, or excessive loading, either separately or
in combination, can cause heat buildup and
possible tire failure.
A
WARNING
Temperature
grades apply to
tires
that are
properly inflated and not over or
underinflat-
ed.
Tire pressure
monitoring
system
(l)
General notes
Appli
es to vehicles
:
wit
h
tire pressure mo nitori ng
system
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflat
-
ed to the
inflation
pressure recommended
by the
vehicle manufacturer
on the vehicle placard or
tire
inflation pressure label.
(If your vehicle has
tires of a different size than the size indicated on
the vehicle placard or tire
inflation
pressure la-
bel, you should determine the proper tire infla-
tion pressure
for
those tires)
.
As
an
added safety feature, your vehicle
has
been
equipped with a
tire
pressure monitoring system
(TPMS) that illuminates a
low
tire pressure tell-
tale when one or more of your tires is significant-
ly
under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you should stop and
""
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