tires Lexus GS430 2006 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2006 PROD. (OM30786U) Service Manual

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552
1 Tire size: For details, see “Tire size” on page
555.
2 DOT and Tire Identification Number (TIN): For
details, see “DOT and Tire Identification Number
(TIN)” on page 555.
3 Tire ply composition and materials : Plies
mean a layer of rubber −coated parallel cords.
Cords mean the strands forming the plies in the
tire.
4 Load limit at maximum cold tire inflation
pressure: For details, see “Checking and
replacing tires” on page 563.
5 Uniform tire quality grading For details, see
“Uniform tire quality grading” on page 557.
6 Maximum cold tire inflation pressure: This
means the pressure to which a tire may be
inflated. For recommended cold tire inflation
pressure, see “Specifications” on page 546.
7 “TUBELESS” or “TUBE TYPE”: A tubeless tire
does not have a tube inside the tire and air is
directly filled in the tire. A tube type tire has a
tube inside the tire and the tube maintains the air
pressure.
8 Radial tires or biasply tires : A radial tire has
“RADIAL” on the sidewall. A tire not marked with
“RADIAL” is a bias −ply tire.
9 Runflat tire (RFT) or standard tire: This
vehicle can be equipped with either run −flat tires
(RFT) or standard tires. A “RFT” or “DSST” mark
is molded on the sidewall of the run −flat tire. For
details, see “Run −flat tires” on page 561.
10 Location of tread wear indicators: For details,
see “Checking and replacing tires” on page 563.
11 Summer tire or all season tire: An all season
tire has “M+S” on the sidewall. The tire not
marked with “M+S” is a summer tire. For details,
see “Types of tires” on page 562.

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554
1 “TEMPORARY USE ONLY”: A compact spare
tire is identified by the phrase “TEMPORARY
USE ONLY” molded into its sidewall. This tire is
designed for temporary emergency use only. For
details, see “Compact spare tire” on page 477.
2 Tire size: For details, see “Tire size” on page
555.
3 DOT and Tire Identification Number (TIN): For
details, see “DOT and Tire Identification Number
(TIN)” on page 555.
4 Load limit at maximum cold tire inflation
pressure: For details, see “Checking and
replacing tires” on page 563.
5 Maximum cold tire inflation pressure: This
means the pressure to which a tire may be
inflated. For recommended cold tire inflation
pressure, see “Specifications” on page 540.
6 Tire ply composition and materials : Plies
mean a layer of rubber −coated parallel cords.
Cords mean the strands forming the plies in the
tire.
7 Location of tread wear indicators: For details,
see “Checking and replacing tires” on page 563.
8 “TUBELESS” or “TUBE TYPE”: A tubeless tire
does not have a tube inside the tire and air is
directly filled in the tire. A tube type tire has a
tube inside the tire and the tube maintains the air
pressure.
9 Radial tires or biasply tires : A radial tire has
“RADIAL” on the sidewall. A tire not marked with
“RADIAL” is a bias −ply tire.

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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.

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561
RUNFLAT TIRES
This vehicle can be equipped with either runflat
tires (RFT) or standard tires. You may continue
driving on the vehicle with runflat tires even if any
tire goes flat. It may be able to run for a maximum
of 160 km (100 miles) at a speed below 90 km/h (55
mph) after the tire pressure warning light comes on.
When you drive your vehicle after the tire pressure
warning light comes on, the tire must be replaced.
Do not use the repaired tire.
G63004
A “RFT” or “DSST” mark is molded on the sidewall of the
run−flat tire.
If you cannot distinguish between the standard tire and
run−flat tire, consult Lexus dealer.
If you have a flat tire, you have to take a different action
depending on whether the tires are standard tires or
run−flat tires.
Runflat tires characteristics:
The vehicle with run −flat tires helps you to continue
driving for up to 160 km (100 miles) at the moderate
speed and do not ever exceed 90 km/h (55 mph) even
with a flat tire. After such usage, the tire must be
replaced. If you are not sure, consult your Lexus dealer.
If you have a flat tire, decrease the speed and drive at
lower speed to reduce the extent to which the tire is
damaged.
However, in some conditions (such as at high
temperatures), you could not continue driving for up to
160 km (100 miles).
The use of non−genuine wheels may prohibit optimum
performance.
The run −flat tires equipped on this vehicle are ones
dedicated for GS430/300. Do not use them on another
model.
Do not mix run− flat tires with standard tires.
The tire warranty book covers the detailed information
on run− flat tires. For details, see the tire warranty book.
Tire pressure warning system
The tire pressure warning system is equipped to warn
you of the low tire inflation pressure. For details, see
“Tire pressure warning system” on page 440.

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562
TYPES OF TIRES
Determine what kind of tires your vehicle 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, summer tires are
inadequate for driving on snow −covered or icy roads.
For driving on snow− covered or icy roads, we
recommend 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 acceleration 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
characteristics, resulting in loss of control.
 Do not use tires other than the manufacturer’s
designated tires, and never mix tires or wheels
of the sizes different from the originals as this
could result in loss of control and could cause
death or serious injury.

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563
ROTATING TIRES
G63008
To equalize tire wear and help extend tire life, Lexus
recommends that you rotate your tires according to
the maintenance schedule. (For scheduled
maintenance information, please refer to the
“Owner’s Manual Supplement / Scheduled
Maintenance”.) However, the most appropriate
timing for tire rotation may vary according to your
driving habits and road surface conditions.
The wheel assemblies must be rotated as illustrated
above.
When rotating tires, check for uneven wear and
damage. Abnormal wear is usually caused by incorrect
tire inflation pressure, improper wheel alignment,
out−of−balance wheels, or severe braking. Before storing radial, snow or studded tires, mark the
direction of rotation and be sure to install them in the
same
direction when using them again. Tires should be
stored in a cool dry place.
CHECKING AND REPLACING TIRES
When to replace your tires
G63003
 1New tread 2Tread wear indicator
3Worn tread
Replace the tires when the tread wear indicators
show. The location of tread wear indicators is
shown by the ”TWI” or ”
Δ” marks, etc., molded on
the sidewall of each tire.

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564
The tires on your Lexus 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 replaced. Vehicles equipped with 245/40R18 93Y or
P245/40R18
93V tires: Your Lexus has been fitted with
specially developed tires which provide exceptional
dynamic performance under general road conditions.
However your riding comfort may worsen a little and
road noise may increase during driving. You may also
notice that your tires will wear more rapidly and tire grip
performance will be reduced on the snowy and/or icy
roads when compared to standard tires. Be sure to have
snow tires or tire chains on the snowy and/or icy roads
and drive carefully with the speed appropriate for road
conditions.
NOTICE
Low profile tire like 245/40R18 93Y or P245/40R18
93V may have greater damage than usual tires to
its tire wheel when receiving impact from the road
surface. Therefore, pay attention to the following.
 Be sure to use with proper tire inflation
pressure. If the tire inflation pressure is low, the
tire may have greater damage. For detailed
information about tire inflation pressure, see
page 542.
 Avoid driving onto high, sharpedged objects
and other road hazards. Failure to do so can
lead to severe tire damage.

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565
The effectiveness of snow tires is lost if the tread
wears down below 4 mm (0.16 in.).
If you have tire damage such as cuts, splits, cracks
deep enough to expose the fabric, or bulges
indicating internal damage, the tire should be
replaced.
If a tire often goes flat or cannot be properly repaired due
to the size or location of a cut or other damage, it should
be replaced. If you are not sure, consult with your Lexus
dealer.
If air loss occurs while driving, do not continue driving.
Driving even a short distance can damage a tire beyond
repair.
Any tires which are over 6 years old must be
checked by a qualified technician even if damage is
not obvious.
Tires deteriorate with age even if they have never or
seldom been used.
This applies also to the spare tire and tires stored for
future use.NOTICE
 When you purchase new tires, consult your
Lexus dealer. If you change from runflat tires
to standard tires, a spare tire should also be
equipped.
 When the tires must be repaired or replaced,
have them repaired or replaced by your Lexus
dealer or an authorized tire dealer. The tire
pressure warning valves and transmitters will
be affected by the installation or removal of
tires.
 When the tires must be replaced, replace the
grommets for tire pressure warning valves and
transmitters as well.

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566
Tire selection
When replacing a tire, use a tire of the same size and
construction, and the same or greater maximum
load as the originally installed tires. Also, all the
tires must be the same brand and have the same
tread patterns.
Using any other size or type of tire may seriously affect
handling, ride, speedometer/odometer calibration,
ground clearance, and clearance between the body and
tires or snow chains.
Check that the maximum load of the replaced tire is
greater than 1/2 of the Gross Axle Weight Ratings
(GAWR) of either the front axle or the rear axle,
whichever is greater. As for the maximum load of the
tire, see the load limit at maximum cold tire inflation
pressure mentioned on the sidewall of the tire, and as for
the Gross Axle Weight Ratings (GAWR), see the
Certification Label. For details about the Certification
Label and sidewall of the tire, see pages 508 and 551.CAUTION
Observe the following instructions. Otherwise, an
accident may occur resulting in death or serious
injuries.
 Do not mix radial, bias belted, or biasply tires
on your vehicle, as this may cause dangerous
handling characteristics resulting in loss of
control.
 Do not use tires other than the manufacturer’s
recommended size, as this may cause
dangerous handling characteristics resulting in
loss of control.

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567
INSTALLING SNOW TIRES ANDCHAINS
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 or radial tires provide better
traction than snow or studded tires.
Snow tire selection
If you need snow tires, select tires of the same size,
construction and load capacity as the originally installed
tires. Also, all the tires must be the same brand and have
the same tread patterns.
Do not use tires other than stated above. Since your vehicle
has radial tires as original equipment, make sure your snow
tires also have radial construction. Do not install studded tires
without first checking local regulations for possible restrictions.
CAUTION
Observe the following instruction. Otherwise, an
accident may occur resulting in death or serious
injuries.
Do not use snow tires other than the manufacturer’s
recommended size, as this may cause dangerous
handling characteristics resulting in loss of control.
Snow tire installation
Snow tires should be installed on all wheels.
Installing snow tires on the rear 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.
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
Regulations regarding the use of tire chains vary
according to location or type of road. Always check local
regulations before installing chains.
Use SAE Class ”S” type radial tire chains, with the exception
of radial cable chains or V− bar type chains.