tire type Lexus GS430 2006 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2005 PROD. OWNER'S MANUAL (OM30649U)

STARTING AND DRIVING
421
CAUTION
Do not rely excessively on the vehicle stability
control system. Even if the vehicle stability control
system is operating, you must always drive carefully
and attentively to avoid serious injury. Reckless
driving will result in an accident. If the slip indicator
light blinks, sounding an alarm, special care should
be taken while driving.
 Only use tires of specified size. The size,
manufacturer, brand and tread pattern for all 4 tires
should be the same. If you use the tires other than
specified, or different type or size, the vehicle
stability control system may not function correctly.
When replacing the tires or wheels, contact your
Lexus dealer.
 In situations where the road surface is covered with
ice or snow, your vehicle should be fitted with snow
tires or tire chains.
G31038
Slip indicator light
If the vehicle is going to skid during driving, the slip indicator
light blinks and an alarm sounds intermittently. Special care
should be taken while driving.
GS430—The slip indicator light comes on when the engine
switch is selected in “IG− ON” mode. The light goes off when
the engine is started.
GS300—The slip indicator light comes on for a few seconds
when the engine switch is selected in “IG −ON” mode.
If the indicator light does not come on when the engine switch
is selected in “IG −ON” mode, contact your Lexus dealer.

STARTING AND DRIVING
426
VEHICLE DYNAMICS
INTEGRATED MANAGEMENT (GS430 only)
Vehicle Dynamics Integrated Management (VDIM) helps
manage control for vehicle stability control system,
antilock brake system, brake assist system, traction
control system, engine output control, hillstart assist
control system and also manages variable gear ratio
steering system and electric power steering system.
In order to control sudden steering wheel operation and
the sideslip on slippery road surfaces, this system
provides excellent vehicle stability by automatically
controlling the brake, engine output and front wheel
angle.
The state of the tires will affect the performance of the vehicle
dynamics integrated management system. Be sure to check
the following:
 Are tires of specified size installed?
 Are tires of identical type installed?
 Do the tires have stipulated tire pressure?
 Are the tires worn?
A problem with the tires or modified suspension systems will
have an adverse effect on the system and may cause a
malfunction, so be careful. When the slip indicator light comes on, and the message
“CHECK ECB” appears on the multi
−information display, the
vehicle dynamics integrated management does not operate.
Have your vehicle checked by your Lexus dealer as soon as
possible.
In addition, when the master warning light comes on, and the
message “CHECK VGRS” or “CHECK P/S” appears on the
multi−information display, the system will not be temporarily
functioning. Although it is no problem in driving as usual, have
your vehicle checked by your Lexus dealer as soon as
possible.
CAUTION
Do not overestimate the vehicle dynamics integrated
management. Even when this management is
functional, there is a limit to vehicle stability, and
irresponsible driving may lead to an accident. When
driving, you should always pay attention to your speed
and keep a safe distance between your vehicle and the
vehicle in front.

STARTING AND DRIVING
434If the low tire pressure warning light does not go off or comes
on during driving, it indicates that tire inflation pressure is low.
Make
sure there is no flat tire. If the light comes on again even
after tire inflation pressure adjustment, you may have a flat tire.
If there is not adequate air pressure in the tires, the light will not
go off.
The light may turn on due to natural causes such as natural air
leaks or tire inflation pressure changes caused by
temperature. In this case, adjusting the tire inflation pressure
will turn off the light.
The tire pressure warning syst em is not a substitute for
checking tire inflation pressure.
For details about adjusting the tire inflation pressure, see
“Checking tire inflation pressure” on page 539.
If the low tire pressure warning light comes on, the action you
must take is different depending on the type of tires used. Vehicles with runflat tires:
Stop your vehicle at a safe place as soon as possible and
check that the tire inflation pressure
is as specified on the tire
and loading information label. If the low tire pressure warning
light comes on even after tire inflation pressure adjustment, it
is probable that you have a flat tire. If you cannot verify the tire
inflation pressure soon, go to the nearest Lexus dealer or
authorized tire dealer at the moderate speed and do not ever
exceed 90 km/h (55 mph) and have all your vehicle’s tires
checked and adjusted. And whether there is a flat tire or not
should be also checked at this time. If any tire must be
replaced, see “If you have a flat tire” on page 468.
If your vehicle is equipped with spare tire, the spare is not
equipped with the tire pressure sensor. So, the low tire
pressure warning light remains on even if the spare tire is
mounted.
The light goes off a few minutes after air is put into the deflated
tire.

SECTION 6 – 3
531
SERVICE PROCEDURES AND
SPECIFICATIONS
Chassis
Specifications (GS430)532
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications (GS300) 535
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking brake fluid 538
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
.
Checking tire inflation pressure 539
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tire information 542
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . .
Run−flat tires 552
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . .
Types of tires 553
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . .
Rotating tires 554
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . .
Checking and replacing tires 554
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing snow tires and chains 558
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing wheels 560
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . .
Aluminum wheel precautions 561
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Suspension and chassis 562
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS
543
1 Tire size: For details, see “Tire size” on page
546.
2 DOT and Tire Identification Number (TIN): For
details, see “DOT and Tire Identification Number
(TIN)” on page 546.
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 554.
5 Uniform tire quality grading For details, see
“Uniform tire quality grading” on page 548.
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 537.
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 552.
10 Location of tread wear indicators: For details,
see “Checking and replacing tires” on page 554.
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 553.

CHASSIS
545
1 “TEMPORARY USE ONLY”: A compact spare
tire is identified by the phrase “TEMPOTRARY
USE ONLY” molded into its sidewall. This tire is
designed for temporary emergency use only. For
details, see “Compact spare tire” on page 471.
2 Tire size: For details, see “Tire size” on page
546.
3 DOT and Tire Identification Number (TIN): For
details, see “DOT and Tire Identification Number
(TIN)” on page 546.
4 Load limit at maximum cold tire inflation
pressure: For details, see “Checking and
replacing tires” on page 554.
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 532.
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 554.
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.

CHASSIS
546
DOT and Tire Identification Number (TIN)
63SA11a
The illustration indicates typical DOT and Tire
Identification Number (TIN)
1“DOT” symbol
2Tire Identification Number (TIN)
3Tire manufacturer’s identification mark
4Tire size code
5Manufacturer’s optional tire type code
(3 or 4 letters)
6Manufacturing week
7Manufacturing year
The “DOT” symbol certifies that the tire conforms to
applicable Federal Motor Vehicle Safety Standards.
Tire size
63ca01
The illustrations indicate typical tire sizes.
1Tire use (P=Passenger car, T=Temporary use)
2Section width (in millimeters)
3Aspect ratio (tire height to section width)
4Speed category (alphabet with one letter)
5Tire construction code
(R=Radial, D=Diagonal)
6Wheel diameter (in inches)
7Load index (2 digits or 3 digits)
8Speed symbol (alphabet with one letter)

CHASSIS
551
Tire related termMeaning
Rim size designationrim diameter and width
Rim type designationthe industry of manufacturer’s designation for a rim by style or code
Rim widthnominal distance between rim flanges
Vehicle maximum load on
the tirethe load on an individual tire that is determined by distributing to eac\
h axle its
share of the maximum loaded vehicle weight and dividing by two
Vehicle normal load on
the tirethe load on an individual tire that is determined by distributing to eac\
h axle its
share of the curb weight, accessory weight, and normal occupant weight
(distributed in accordance with Table 1 that follows) and dividing by two
Weather sidethe surface area of the rim not covered by the inflated tire
Table 1 – Occupant loading and distribution for vehicle normal load for various designated seating capacities
Designated seating capacity, Number of occupants
Vehicle normal load,
Number of occupantsOccupant distribution in a normally loaded vehicle
2 through 422 in front
5 through 1032 in front, 1 in second seat

CHASSIS
553
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.

CHASSIS
557
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 500 and 542.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.