552
GS350_OM_OM30F69U_(U)
8-1. Specifications
This information has been prepared in accordance with regulations issued
by the National Highway Traffic Safety Administration of the U.S. Depart-
ment of Transportation.
It provides the purchasers and/or prospective purchasers of Lexus vehi-
cles 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 Require-
ments 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 govern-
ment 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. Performance may differ significantly from the norm due to variations in
driving habits, service practices and differences in road characteristics and cli-
mate.
■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.
Uniform Tire Quality Grading
GS350_OM_OM30F69U_(U)
5538-1. Specifications
8
Vehicle specifications
■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 labora-
tory 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.
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 of a tire assume that it 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.
