tires LEXUS SC300 1999 User Guide

MAINTENANCE
315
DOES YOUR VEHICLE NEEDREPAIRING?
Be on the alert for changes in performance and sounds, and
visual tip±offs that indicate service is needed. Some
important clues are:

Engine missing, stumbling, or pinging

Appreciable loss of power

Strange engine noises

A fluid leak under the vehicle (However, water dripping
from the air conditioning after use is normal.)

Change in exhaust sound (This may indicate a dangerous
carbon monoxide leak. Drive with the windows open and
have the exhaust system checked immediately.)

Flat±looking tires, excessive tire squeal when cornering,
uneven tire wear

Vehicle pulls to one side when driving straight on a level
road

Strange noises related to suspension movement

Loss of brake effectiveness, spongy feeling brake pedal,
pedal almost touches floors, vehicle pulls to one side when
braking

Engine coolant temperature continually higher than
normal
If you notice any of these clues, take your vehicle to your
Lexus dealer as soon as possible. It probably needs
adjustment or repair.

SECTION 6 ± 3
353
SERVICE PROCEDURES AND
SPECIFICATIONS
Chassis
Specifications (SC400) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
355
Specifications (SC300) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
357
Checking brake fluid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
359
Checking power steering fluid . . . . . . . . . . . . . . . . . . . . . . . .
361
Checking tire pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
363
Rotating tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . \
. .
365
Checking and replacing tires . . . . . . . . . . . . . . . . . . . . . . . . . .
365
Installing snow tires and chains . . . . . . . . . . . . . . . . . . . . . . .
369
Replacing wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
372
Aluminum wheel precautions . . . . . . . . . . . . . . . . . . . . . . . . .
372
Suspension and chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS
356± STEERING
Freeplay
Power steering fluid
Less than 30 mm (1.2 in.)Automatic transmission fluid DEXRONII or III
± TIRES AND WHEELS
Tire size
Tire inflation pressure Recommended cold tire inflation pressure
Wheel size
Wheel nut torque
225/55R16 94V
Front 220 kPa (2.2 kgf/cm
2 or bar, 32 psi)
Rear 220 kPa (2.2 kgf/cm2 or bar, 32 psi)
16 x 7 JJ or 16 x 6 1/2 JJ
103 N´m (10.5 kgf´m, 76 ft´lbf.)

CHASSIS
358± STEERING
Freeplay
Power steering fluid
Less than 30 mm (1.2 in.)Automatic transmission fluid DEXRONII or III
± TIRES AND WHEELS
Tire size
Tire inflation pressure Recommended cold tire inflation pressure
Wheel size
Wheel nut torque
225/55 R16 94V
Front 220 kPa (2.2 kgf/cm
2 or bar, 32 psi)
Rear 220 kPa (2.2 kgf/cm2 or bar, 32 psi)
16 x 6
1/2 JJ
103 N´m (10.5 kgf´m, 76 ft´lbf.)

CHASSIS
364The recommended cold tire pressures, tire size and the
vehicle capacity weight are given on the label.
You should check the tire pressures every two weeks, or at
least
once a month. And don't forget the spare! The pressure
for the spare tire should be same with that for the standard tire.
(See page 356 or 358.) Incorrect tire pressure can reduce tire
life and make your vehicle less safe to drive.
Low tire pressure results in excessive wear, poor handling,
reduced fuel economy, and the possibility of blowouts from
overheated tires. Also, low tire pressure can cause poor
sealing of the tire bead. If the tire pressure is excessively low,
there is the possibility of wheel deformation and/or tire
separation. So keep your tire pressures at the proper level. If
a tire needs frequent refilling, have it checked by your Lexus
dealer. High tire pressure produces a harsh ride, handling problems,
excessive wear at the center of the tire tread, and a greater
possibility of tire damage from road hazards.
The following instructions for checking tire pressure should
be observed:

The pressure should be checked only when the tires are
cold. If your vehicle has been parked for at least 3 hours
and has not been driven for more than 1.5 km or 1 mile
since, you will get an accurate cold tire pressure reading.
 Always use a tire pr essure gauge. The appearance of the
tire can be misleading. Besides, tire pressures that are even
just a few pounds off can degrade handling and ride.
 Do not bleed or reduce tire pressure after driving. It is
normal for the tire pressure to be higher after driving.
 Never exceed the vehicle capacity weight. The
passengers and luggage weight should be located so that
the vehicle is balanced.
 Be sure to reinstall the tire valve caps. Without the valve
caps, dirt or moisture could get into the valve core and
cause air leakage. If the caps have been lost, have new
ones put on as soon as possible.

CHASSIS
365
ROTATING TIRES
To equalize tire wear and help extend tire life, Lexus
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 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.CHECKING AND REPLACINGTIRES
When to replace your tires

CHASSIS
366
Replace the tires when the tread wear indicators show.
The location of the tread wear indicators is shown by the
ºTWIº or º
Dº marks 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 an air loss occurs while driving, do not continue driving
with a deflated tire. 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 also applies to the spare tire and tires stored for future
use.

CHASSIS
367
Uniform tire quality grading
This information has been prepared in accordance with
regulations issued by the National Highway T raffic 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. These quality grades are molded on the
sidewall. 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 th eir 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

CHASSIS
368required by law. Warning: The temperature grade of 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.
Tire selection
When replacing a tire, use only the same size and
construction as originally installed and with the same or
greater load capacity.
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.
Do not mix radial, belted, or conventional tires on your
vehicle.
Do not use tires or wheels other than the manufacturer's
recommended size.
It can 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.

CHASSIS
369
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 road, conventional or radial tires provide better
traction than snow or studded tires.
Snow tire selection
If you need snow tires, select the same size, construction
and load capacity as the original tires on your Lexus.
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.
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.