1998 TOYOTA SIENNA traction control

name. SIENNA (U)
178
Suspension and chassis
CAUTION
Do not modify the suspension/chassis
with lift kits, spacers, springs, etc. It
can cause dangerous vehicle handling
characteristics, resulting in loss of
control.
Types of tires
Determine what kind of tires your ve-
hicle is originally equipped with.
1. Summer tires
Summer tires are high−speed capability
tires best suited to highway driving under
dry conditions.
Since summer tires do not have the same
traction performance as snow tires, sum-
mer tires are inadequate for driving on
snow−covered or icy roads. For driving on
snow−covered or icy roads, we recom-
mend using snow tires. If installing snow
tires, be sure to replace all four tires.
2. All season tires
All season tires are designed to provide
better traction in snow and to be adequate
for driving in most winter conditions, as
well as for use all year round.
All season tires, however, do not have
adequate traction performance compared
with snow tires in heavy or loose snow.
Also, all season tires fall short in accel-
eration and handling performance
compared with summer tires in highway
driving.CAUTION
Do not mix summer and all season
tires on your vehicle as this can
cause dangerous handling charac-
teristics, resulting in loss of con-
trol.
Do not use tires other than the
manufacturer ’s designated tires, and
never mix tires or wheels of the
sizes different from the originally
equipped tires and wheels.
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Rotating tires
Steel wheels with a compact spare tire
and aluminum wheels
Steel wheels without a compact spare tire
To equalize the wear and help extend
tire life, Toyota recommends that you
rotate your tires approximately every
12000 km (7500 miles). However, the
most appropriate timing for tire rotation
may vary according to your driving hab-
its and road surface conditions.
See ”If you have a flat tire” in Part 4 for
tire change procedure.
When rotating tires, check for uneven
wear and damage. Abnormal wear is usu-
ally caused by incorrect tire pressure, im-
proper wheel alignment, out−of−balance
wheels, or severe braking.
CAUTION
Do not include a compact spare tire
when rotating the tires. It is designed
for temporary use only.
WHEN TO USE SNOW TIRES OR
CHAINS
Snow tires or chains are recommended
when driving on snow or ice.
On wet or dry roads, conventional tires
provide better traction than snow tires.
SNOW TIRE SELECTION
If you need snow tires, select the same
size, construction and load capacity as
the original tires on your Toyota.
Do not use tires other than those men-
tioned above. Do not install studded tires
without first checking local regulations for
possible restrictions.
SNOW TIRE INSTALLATION
Snow tires should be installed on all
wheels.
Installing snow tires on the front wheels
only can lead to an excessive difference
in road grip capability between the front
and rear tires which could cause loss of
vehicle control.
When storing removed tires, you should
store them in a cool dry place. Mark the
direction of rotation and be sure to install
them in the same direction when replac-
ing.
Installing snow tires and
chains
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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 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 con-
trolled conditions on specified government
test surfaces of asphalt and concrete. A
tire marked C may have poor traction per-
formance.
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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