tires Lexus GX470 2005 Pictorial Index / LEXUS 2005 GX470 (OM60B11U) Owner's Guide

CHASSIS
582
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 Ð All passenger car 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 ATreadwear
Ð 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 Ð 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 Ð 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.

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583
Temperature A, B, C Ð 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 grade for this tire
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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587
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.
The details about how to distinguish summer tires
from all season tires are described on page 578.
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.

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588
ROTATING TIRES
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 ªOwner's Manual Supplement/Scheduled
Maintenanceº.) 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 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.

CHASSIS
589
CHECKING AND REPLACING TIRES
When to replace your tires

1New tread2Tread wear indicator
3Worn tread
Replace the tires when the tread wear indicators
show. The location of the tread wear indicators
is shown by the marks such as ªTWIº or ª
Dº
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.

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590
This applies also to the spare tire and tires stored
for future use.
Tire selection
When replacing a tire, use a tire of the same size
and construction, and the same or greater load
capacity 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
Certification Label and sidewall of the tire, see pages
535 and 578.
CAUTION
Observe the following instructions. Otherwise,
an accident may occur resulting in death or
serious injuries.
Do not mix radial, bias belted, or bias±ply 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.
 Do not use tires of different brands, sizes,
construction or tread patterns, as this may
cause dangerous handling characteristics
resulting in loss of control.

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591
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 instructions. 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.
 Do not use snow tires of different brands, sizes,
construction or tread patterns, 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 105 km/h (65 mph) with any type of
snow tires.

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592
Tire chain selection

1 Side chain2 Cross chain
Use the tire chains of correct size.
For P265/65R17 tires, use the following type chains.
mm (in.)
A: Diameter of side chain 5.0 (0.20)
B: Width of side chain 18.0 (0.71)
C: Length of side chain 46.0 (1.81)
D: Width of cross chain 22.6 (0.89)
E: Length of cross chain 38.1 (1.5)
F: Diameter of cross chain 6.3 (0.25) Regulations regarding the use of tire chains vary
according to
location or type of road. Always check local
regulations before installing chains.

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594
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 Ð 1.0 km (1/4 Ð 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 locked±wheel 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.

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597
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.
SUSPENSION AND CHASSIS
CAUTION
Do not modify the suspension/chassis with lift kits,
spacers, springs, etc. It can cause dangerous handling
characteristics, resulting in loss of control.