Uniform Tire Quality Grading - Toyota 4Runner 1998 Operating Manual

Uniform tire quality grading

This information has been prepared in
accordance with regulations issued by
the National Highway Traffic Safety
Administration of the U.S. Department
of Transportation. It provides the pur-
chasers and/or prospective purchasers
of Toyota vehicles with information on
uniform tire quality grading.
Your Toyota dealer will help answer
any questions you may have as you
read this information.
DOT quality grades—All passenger
vehicle tires must conform to Fed-
eral Safety Requirements in addition
to these grades. These
grades are molded on the sidewall.
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 char-
acteristics and climate.
Traction A, B,
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 condi-
tions on specified government
surfaces of asphalt and concrete. A
tire marked C may have poor traction
performance.
Warning: The traction grade assigned
to this tire is based
(straight ahead) traction
does not include cornering (turning)
traction.
quality Temperature A, B, C—The tempera-
ture grades are A (the highest), B,
and C, representing the tire's resis-
tance to the generation of heat and its
ability to dissipate heat when tested
under controlled conditions on a speci-
fied indoor laboratory test wheel. Sus-
tained high temperature can cause the
material of the tire to degenerate and
reduce tire life, and excessive temper-
ature can lead to sudden tire failure.
The grade C corresponds to a level of
performance which all passenger car
tires must meet under the Federal Mo-
tor Vehicle Safety Standard No. 109.
Grades B and A represent higher lev-
els of performance on the laboratory
test wheel than the minimum required
by law.
C—The traction Warning: The temperature grades for
this tire are established for a tire that
is properly
loaded. Excessive speed, underinfla-
tion, or excessive loading, either sepa-
test rately or in combination, can cause
heat buildup and possible tire failure.
on braking
tests and
4RUNNER (1998)
inflated and not over-