2008 Lexus IS250 wheel

419
6-1. Specifications
6
Vehicle specifications
Type E
Ti r e s i z e
Front tires: 225/40R18 88Y
Rear tires: 255/40R18 95Y
Spare tire: T145/70R17 106M
Front and rear tire inflation pres-
sure
(Recommended cold tire inflation
pressure)
Driving under normal conditionsFront:
35 psi (240 kPa, 2.4 kgf/cm
2 or bar)*
Rear:
38 psi (260 kPa, 2.6 kgf/cm
2 or bar)*
Spare:
60 psi (420 kPa, 4.2 kgf/cm
2 or bar)
*: When driving at high speeds above 100 mph
(160 km/h), in countries where such speeds are
permitted by law, add 7.2 psi (50 kPa, 0.5 kgf/
cm
2 or bar) to the front tires and rear tires.
Never exceed the maximum cold tire inflation
pressure indicated on the tire sidewall.
Wheel size
Front wheels: 18  8J
Rear wheels: 18 8 1 /2J
Spare wheel: 17  4T
Wheel nut torque76 ft•lbf (103 N•m, 10.5 kgf•m)

426
6-1. Specifications
Typical DOT and tire identification number (TIN)DOT symbol
*
Tire Identification Number (TIN)
Tire manufacturer's identifica-
tion mark
Tire size code
Manufacturer's optional tire
type code (3 or 4 letters)
Manufacturing week
Manufacturing year
*: The DOT symbol certifies thatthe tire conforms to applicable
Federal Motor Vehicle Safety
Standards.
Tire size
■ Typical tire size information
The illustration indicates typical
tire size.
Ti r e u s e
(P = Passenger car,
T = Temporary use)
Section width (millimeters)
Aspect ratio
(tire height to section width)
Tire construction code
(R = Radial, D = Diagonal)
Wheel diameter (inches)
Load index (2 or 3 digits)
Speed symbol
(alphabet with one letter)

427
6-1. Specifications
6
Vehicle specifications
■Tire dimensions
Section width
Ti r e h e i g h t
Wheel diameter
Tire section names
Bead
Sidewall
Shoulder
Tread
Belt
Inner liner
Reinforcing rubber
Carcass
Rim lines
Bead wires
Chafer
Uniform Tire Quality GradingThis information has b een prepared in accordance with regulations
issued by the National Highway Tr affic Safety Administration of the
U.S.A. Department of Transportation.
It provides the purchasers and/or prospective purchasers of Lexus vehi-
cles with information on uniform tire quality grading.
Your Lexus dealer will help answer an y questions you may have as you read
this information.

429
6-1. Specifications
6
Vehicle specifications
■Temperature A, B, C
The temperature grades are A (the hi ghest), 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 fail-
ure.
The grade C corresponds to a level of performance which all passenger car
tires must meet under the Federal Mo tor 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 excess ive loading, either separately or in
combination, can cause heat build up and possible tire failure.
Glossary of tire terminology
Tire related termMeaning
Accessory weight
The combined weight (in excess of those standard
items which may be replaced) of automatic transmis-
sion, power steering, power brakes, power windows,
power seats, radio and heater, to the extent that these
items are available as factory-installed equipment
(whether installed or not)
Cold tire inflation pres-
sureTire pressure when the vehicle has been parked for
three hours or more, or has not been driven more
than 1 mile or 1.5 km under that condition
Curb weight
The weight of a motor vehicle with standard equip-
ment, including the maximum capacity of fuel, oil and
coolant, and if so equipped, air conditioning and
additional weight optional engine

430
6-1. Specifications
Maximum inflation pres-
sureThe maximum cold inflated pressure to which a tire
may be inflated, shown on the sidewall of the tire
Maximum loaded vehicle
weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant weight150 lb. (68 kg) times the number of occupants speci-
fied in the second column of Table 1
* that follows
Production options
weight
The combined weight of installed regular production
options weighing over 5 lb. (2.3 kg) in excess of the
standard items which they replace, not previously
considered in curb weight or accessory weight,
including heavy duty brakes, ride levelers, roof rack,
heavy duty battery, and special trim
Vehicle capacity weight
(Total load capacity)The rated cargo and luggage load plus 150 lb. (68
kg) times the vehicle's designated seating capacity
Occupant distributionDistribution of occupants in a vehicle as specified in
the third column of Table 1
* below
Recommended inflation
pressureCold tire inflation pressure recommended by a man-
ufacturer.
RimA metal support for a tire or a tire and tube assembly
upon which the tire beads are seated
Rim diameter
(Wheel diameter)Nominal diameter of the bead seat
Rim size designationRim diameter and width
Rim type designationThe industry manufacturer's designation for a rim by
style or code
Tire related termMeaning

434
6-1. Specifications
Tire related termMeaning
Ply separationA parting of rubber compound between adjacent
plies
Pneumatic tire
A mechanical device made of rubber, chemicals, fab-
ric and steel or other mate rials, that, when mounted
on an automotive wheel, provides the traction and
contains the gas or fluid that sustains the load
Radial ply tire
A pneumatic tire in which the ply cords that extend to
the beads are laid at substantially 90 degrees to the
centerline of the tread
Reinforced tire
A tire designed to operate at higher loads and at
higher inflation pressures than the corresponding
standard tire
Section width
The linear distance between the exteriors of the side-
walls of an inflated tire, excluding elevations due to
labeling, decoration, or protective bands
SidewallThat portion of a tire between the tread and bead
Sidewall separationThe parting of the rubber compound from the cord
material in the sidewall
Snow tire
A tire that attains a traction index equal to or greater
than 110, compared to the ASTM E-1136 Standard
Reference Test Tire, when using the snow traction test
as described in ASTM F-1805-00, Standard Test
Method for Single Wheel Driving Traction in a
Straight Line on Snow-and Ice-Covered Surfaces,
and which is marked with an Alpine Symbol (
)
on at least one sidewall
Te s t r i mThe rim on which a tire is fitted for testing, and may be
any rim listed as appropriate for use with that tire

435
6-1. Specifications
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Vehicle specifications
*: Table 1  Occupant loading and distribution for vehicle normal load for
various designated seating capacities
Tire related termMeaning
Tr e a dThat portion of a tire that comes into contact with the
road
Tr e a d r i bA tread section running circumferentially around a
tire
Tr e a d s e p a r a t i o nPulling away of the tread from the tire carcass
Treadwear indicators
(TWI)The projections within the principal grooves
designed to give a visual indication of the degrees of
wear of the tread
Wheel-holding fixtureThe fixture used to hold the wheel and tire assembly
securely during testing
Designated seating
capacity, Number of occupantsVehicle 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
11 through 155
2 in front, 1 in second
seat, 1 in third seat, 1 in fourth seat
16 through 207
2 in front, 2 in second
seat, 2 in third seat, 1 in fourth seat

450
Alphabetical index
Alphabetical index
A/C ............................................................. 192
ABS.............................................................. 170
AFS .............................................................. 144
Adaptive front lighting system ......... 144
Air conditioning filter .......................... 322
Air conditioning systemAir conditioning filter ....................... 322
Automatic air conditioning system .................................................... 192
Airbags Airbag operating conditions.............81
Airbag precautions for your child.......................................................... 85
Airbag warning light ..........................361
Curtain shield airbag operating
conditions.............................................. 82
Curtain shield airbag precautions .......................................... 85
Front passenger occupant classification system......................... 90
General airbag precautions ........... 85
Locations of airbags............................ 79
Modification and disposal of airbags .................................................... 89
Proper driving po sture ............. 77, 85
Side airbag operating conditions.............................................. 82
Side airbag precautions .................... 85
SRS airbags ............................................. 79 Alarm .............................................................74
Antenna ....................................................208
Anti-lock brake system ........................170
Armrest .................................................... 255
Ashtrays.................................................... 248
Audio input.............................................. 228
Audio system
Antenna.................................................. 208
Audio input ........................................... 228
AUX adapter ...................................... 228
CD player/changer ............................. 211
MP3/WMA disc..................................217
Optimal use ..........................................225
Portable music player ..................... 228
Radio ....................................................... 204
Steering wheel audio switch.........229
Automatic air conditioning system ......................................................192
Automatic headlight leveling system ......................................................145
Automatic light control system.........143
Automatic transmission Automatic transmission ....................122
If the shift lever cannot be shifted from P....................................392
S mode ..................................................... 124
AUX adapter ......................................... 228A