2005 LEXUS LS430 Owners Manual

CHASSIS
478
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

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479
TYPES OF TIRES
Determine what kind of tires your vehicle is originally
equipped with.
1. 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.
2. 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.
CAUTION
 Do not mix all season and summer 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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480
ROTATING TIRES
63L020a
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.
Initial adjustment of th e tire pressure warning
system is necessary after you have rotated your
tires. See “Tire pressure warning system” on page
370.

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481
CHECKING AND REPLACING TIRES
When to replace your tires
62L026
 1New tread 2Tread wear indicator
3Worn tread
Replace the tires when the tread wear indicators
show. The location of the tread wear indicators is
shown by the “TWI” or “
Δ” marks, etc., molded on
the sidewall of each tire.
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. 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.

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482
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.
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 434 and 471.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.
If you need to change from conventional tires to radial
tires or vice versa, replace them as a set.

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483
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.
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.

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484
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 0.5 1.0 km (1/4 1/2 mile).
When installing chains on your tires, carefully follow the
instructions of the chain manufacturer.
CAUTION
Do not exceed 50 km/h (30 mph) or the chain
manufacturer’s recommended speed limit,
whichever is lower.
 Drive carefully avoiding bumps, holes, and sharp
turns, which may cause the vehicle to bounce.
 Avoid sharp turns or lockedwheel braking, as use of
chains may adversely affect vehicle handling.
 When driving with chains installed, be sure to drive
carefully. Slow down before entering curves to avoid
losing control of the vehicle. Otherwise an accident
may occur.
If the chains are installed, the tire pressure warning
system may not operate properly. See “Tire pressure
warning system” on page 370.
REPLACING WHEELS
When to replace your wheels
If you have wheel damage such as bending, cracks or
heavy corrosion, the wheel should be replaced.
If you fail to replace a damaged wheel, the tire may slip off the
wheel or cause loss of handling control.
Wheel selection
When replacing wheels, care should be taken to ensure
that they are equivalent to those removed in load capacity,
diameter, rim width, and offset.
Correct replacement wheels are available at your Lexus
dealer.
A wheel of a different size or type may adversely affect
handling, wheel and bearing life, brake cooling,
speedometer/odometer calibration, stopping ability, headlight
aim, bumper height, vehicle ground clearance, and tire or snow
chain clearance to the body and chassis.
Replacement with used wheels is not recommended as they
may have been subjected to rough treatment or high mileage
and could fail without warning. Also, bent wheels which have
been straightened may have hidden structural damage and
therefore should not be used. Never use an inner tube in a
leaking wheel which is designed for a tubeless tire.

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CAUTION
Observe the following instruction. Otherwise, an
accident may occur resulting in death or serious
injuries.
Do not use wheels other than the manufacturer’s
recommended size, as this may cause dangerous
handling characteristics resulting in loss of control.
Initial adjustment of the tire pressure warning system is
necessary after you have replaced your wheels. See “Tire
pressure warning system” on page 370.
ALUMINUM WHEEL PRECAUTIONS
 When installing aluminum wheels, check that the wheel
nuts are tight after driving your vehicle the first 1600 km
(1000 miles).
 If you have rotated, repaired, or changed your tires, check
that the wheel nuts are still tight after driving 1600 km (1000
miles).
 When using tire chains, be careful not to damage the
aluminum wheels.
 Use only Lexus wheel nuts and wrench designed for your
aluminum wheels.
 When balancing your wheels, use only Lexus balance
weights or equivalent and a plastic or rubber hammer.
 As with any wheel, periodically check your aluminum
wheels for damage. If damaged, replace immediately.