2006 Lexus GS430 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2006 PROD. OWNER'S MANUAL (OM30786U)

CHASSIS
553
Tire symbols (Compact spare tire)
G63007
The illustration indicates typical tire symbols.

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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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555
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
63ca01a
 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)
4Tire construction code
(R=Radial, D=Diagonal)
5Wheel diameter (in inches)
6Load index (2 digits or 3 digits)
7Speed symbol (alphabet with one letter)

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556
G63005
 1Section width
2Tire height
3Wheel diameter
Name of each section of tire
63sa14
 1Bead
2Sidewall
3Shoulder
4Tread
5Belt
6Inner liner
7Reinforcing rubber
8Carcass
9Rim lines
10Bead wires
11Chafer

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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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558
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation
pressuretire pressure when the vehicle has been parked for at least 3 hours or m\
ore, or it
has not been driven more than 1.5 km or 1 mile under that condition
Maximum inflation
pressurethe maximum cold inflation pressure to which a tire may be inflated and \
it is shown
on the sidewall of the tire
Recommended inflation
pressurecold tire inflation pressure recommended by a manufacturer
Accessory weight
the combined weight (in excess of those standard items which may be rep\
laced) of
automatic transmission, power steering, power brakes, power windows, pow\
er
seats, radio, and heater, to the extent that these items are available as
factory−installed equipment (whether installed or not)
Curb weight
the weight of a motor vehicle with standard equipment including the maxi\
mum
capacity of fuel, oil, and coolant, and, if so equipped, air conditionin\
g and
additional weight optional engine
Maximum loaded vehicle
weight
the sum of —
(a) curb weight;
(b) accessory weight;
(c) vehicle capacity weight; and
(d) production options weight

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559
Tire related termMeaning
Normal occupant weight68 kg (150 lb.) times the number of occupants specified in the second \
column of
Table 1 that follows
Production options weight
the combined weight of those installed regular production options weighi\
ng over
2.3 kg (5 lb.) in excess of those standard items which they replace, n\
ot previously
considered in curb weight or accessory weight, including heavy duty brak\
es, ride
levelers, roof rack, heavy duty battery, and special trim
Vehicle capacity weight
(Total load capacity)the rated cargo and luggage load plus 68 kg (150 lb.) times the vehicl\
e’s
designated seating capacity
Intended outboard
sidewall
(a) the sidewall that contains a whitewall, bears white lettering or bearsmanufacturer, brand, and/or model name molding that is higher or deeper than
the same molding on the other sidewall of the tire, or
(b) the outward facing sidewall of an asymmetrical tire that has a particula\
r side that must always face outward when mounted on a vehicle
Occupant distributiondistribution of occupants in a vehicle as specified in the third column \
of Table 1 that
follows
Rima metal support for a tire or a tire and tube assembly upon which the ti\
re beads are
seated
Rim diameter
(Wheel diameter)nominal diameter of the bead seat

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560
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