1999 TOYOTA 4RUNNER run flat

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242
Checking and replacing tires
Tread wear indicator
CHECKING YOUR TIRES
Check the tire tread for the tread wear
indicators. If the indicators show, re-
place the tires.
The tires on your Toyota have built- in
tread wear indicators to help you know
when the tires need replacement. When
the tread depth wears to 1.6 mm (0.06
in.) or less, the indicators will appear. If
you can see the indicators in two or more
adjacent grooves, the tire should be re-
placed. The lower the tread, the higher
the risk of skidding.
The effectiveness of snow tires is lost
if the tread wears down below 4 mm
(0.16 in.). Check the tires regularly for damage
such as cuts, splits and cracks. If any
damage is found, consult with a techni-
cian and have the tire repaired or re-
placed.
Even if the damage does not appear seri-
ous, a qualified technician should examine
the damage. Objects which have pene-
trated the tire may have caused internal
damage.
Any tires which are over six years old
must be checked by a qualified techni-
cian even if damage is not obvious.
Tires deteriorate with age even if they
have never or seldom been used.
This also applies to the spare tire and
tires stored for future use.
REPLACING YOUR TIRES
When replacing a tire, use only the
same size and construction as original-
ly installed and with the same or great-
er load capacity.
Using any other size or type of tire may
seriously affect handling, ride, speedome-
ter/odometer calibration, ground clearance,
and clearance between the body and tires
or snow chains.CAUTION

Do not mix radial, bias belted, or
bias- ply tires on your vehicle. It
can cause dangerous handling char-
acteristics, resulting in loss of con-
trol.
Do not use tires or wheels other
than the manufacture's recom-
mended size.
Toyota recommends all four tires, or at
least both of the front or rear tires be
replaced at a time as a set.
See ºIf you have a flat tireº in Part 4 for
tire change procedure.
When a tire is replaced, the wheel
should always be balanced.
An unbalanced wheel may affect vehicle
handling and tire life. Wheels can get out
of balance with regular use and should
therefore be balanced occasionally.
When replacing a tubeless tire, the air
valve should also be replaced with a
new one.

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Rotating tires
To equalize tire 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 ºIf you have a flat tireº 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.
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 w
heels
only can lead to an excessive difference
in road grip capab ility 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
replacing.
CAUTION
Do not drive with the snow tires
incorrectly inflated.
Never drive over 120 km/h (75 mph)
with any type of snow tires.
TIRE CHAIN SELECTION
Use the tire chains of correct size.
Regulations regarding the use of tire
chains vary according to location or
type of road, so always check them
before installing chains.
CHAIN INSTALLATION
Install the chains on the rear tires as
tightly as possible. Do not use tire
chains on the front tires. Retighten
chains after driving 0.5Ð1.0 km
(1/4Ð1/2 mile).
When installing chains on your tires, care-
fully follow the instructions of the chain
manufacturer.
If wheel covers are used, they will be
scratched by the chain band, so remove
the covers before putting on the chains.
Installing snow tires and
chains

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268
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 gradesÐAll passenger ve-
hicle tires must conform to Federal
Safety Requirements in addition to
these grades. These quality grades are
molded on the sidewall.
Treadwear
ÐThe 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
ÐThe 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 ÐThe temperature
grades are A (the highest), B, and C,
representing the tire's resistance to the
generation of heat and its ab ility 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.