climate control TOYOTA SIENNA 1999 Owners Manual

name. SIENNA (45403U)
272
Uniform tire quality grading
This information has been prepared in ac-
cordance with regulations issued by the
National Highway Traffic Safety Adminis-
tration of the U.S. Department of Trans-
portation. It provides the purchasers 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 ve-
hicle tires must conform to Federal
Safety Requirements in addition to
these grades. These quality 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 condi-
tions of their use, however, and may de-
part significantly from the norm due to
variations in driving habits, service prac-
tices and differences in road characteris-
tics 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 mea-
sured under controlled conditions on spe-
cified 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 dissi-
pate heat when tested under controlled
conditions on a specified indoor laboratory
test wheel. Sustained high temperature
can cause the material of the tire to de-
generate and reduce tire life, and exces-
sive temperature can lead to sudden tire
failure. The grade C corresponds to a lev-
el 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 perfor-
mance 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 prop-
erly inflated and not overloaded. Exces-
sive speed, underinflation, or excessive
loading, either separately or in combina-
tion, can cause heat buildup and possible
tire failure.
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