Lexus GS430, User Manual

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CHASSIS
557
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 purchasers and/or
prospective purchasers of Lexus vehicles with
information on uniform tire quality grading.
Your Lexus dealer will help answer any questions
you may have as you read this information.
DOT quality grades − All passenger vehicle tires
must conform to Federal Safety Requirements in
addition to these grades. Quality grades can be
found where applicable on the tire sidewall between
tread shoulder and maximum section width. For
example: Treadwear 200 Traction AA Temperature
A
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 AA, A, B, C
−
The traction grades, from highest
to lowest, are AA, 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 (straight ahead) traction tests and
does not include cornering (turning) traction.
Temperature A, B, C
−
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 material of the tire to
degenerate and reduce tire life, and excessive
temperature 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 Motor
Vehicle Safety Standard No. 109. Grades B and A
represent higher levels of performance on the laboratory
test wheel than the minimum required by law.
Warning: The temperature grades for this tire are
established for a tire that is properly inflated and not
overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.