1997 Pontiac Grand Am Owner's Manual - Page 273

1997 Pontiac Grand Am Manual

Page 273 highlights

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 onthe sidewalls of most passenger car tires. The Uniform TireQuality 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 10 to 12 inches (25 to 30 cm), or to somelimited-production tires. While the tires available on General Motors passenger cars andlight 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 onthe 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 B, and A, 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. 6-46

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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
10
to 12 inches (25 to
30
cm),
or to
somelimited-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.
6-46