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 tempomy use spare
tires, tires with nominal rim diameters of
10
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
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
--
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.
6-49
To Next Page
Loading...
