User Guide
-
A
CAUTION:
Mixing tires could cause you to lose control while
driving.
If
you mix tires of different sizes or types
(radial and bias-belted tires), the vehicle may not
handle properly, and you could have a crash.
Using tires of different sizes may also cause
damage to your vehicle.
Be
sure
to
use the
same
size and type tires on all wheels.
Uniform Tire Quality Grading
The following information relates
to
the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires
by
treadwear, traction and temperature performance.
(This
applies only
to
vehicles sold
in
the United States.)
The
grades are molded
on
the sidewalls
of
most
passenger car tires. The Uniform Tire Quality Grading
system does
not
apply to deep tread, winter-type snow
tires, space-saver or temporary
use
spare tires, tires with
nominal rim diameters
of
IO
to
12
inches
(25
to
30
cm),
or
to
some limited-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades,
they
must
also
conform
to
Federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
Treadwear
The treadwear 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
(1
1/2)
times as
well
on
the government course as a tire
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.
E
at-aded
100.
The relative performance of tires depends
Traction
--
A,
B,
C
The traction grades, from highest to lowest,
are
A,
B,
and
C, and they 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.
Warning: The traction grade assigned
to
this, tire
is
based
on
braking (straightahead) traction tests and does
not
include cornering (turning) traction.
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