tires Lexus IS250 2012 Service Manual

535
6-1. Specifications
6
Vehicle specifications
IS350/250_UTy p e E
■ Compact spare tire
Ti r e s i z eFront tires: 225/40R18 88W
Rear tires: 255/40R18 95W
Front and rear tire inflation pres-
sure
(Recommended cold tire inflation
pressure)
Driving under normal conditions
Front:
35 psi (240 kPa, 2.4 kgf/cm
2 or bar)*
Rear:
38 psi (260 kPa, 2.6 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 sizeFront wheels: 18 × 8J
Rear wheels: 18 × 8 1 /2J
Wheel nut torque76 ft•lbf (103 N•m, 10.5 kgf•m)
Ti r e s i z e
Ty p e A
T125/70D17 98M
Ty p e B
T145/70D17 106M
Tire inflation pressure
(Recommended cold tire inflation
pressure)
60 psi (420 kPa, 4.2 kgf/cm2 or bar)
Wheel size17 × 4T

542
6-1. Specifications
IS350/250_U
Radial tires or bias-ply tires
A radial tire has “RADIAL” on the sidewall. A tire not marked “RADIAL” is
a bias-ply tire.
TUBELESS or TUBE TYPE
A tubeless tire does not have a tube and air is directly filled in the tire. A
tube type tire has a tube inside the ti re and the tube maintains the air pres-
sure.
Load limit at maximum cold tire inflation pressure ( →P. 4 1 9 )
Maximum cold tire inflation pressure ( →P. 5 3 1 )
This means the pressure to which a tire may be inflated.
Uniform tire quality grading
For details, see “Uniform Tire Quality Grading” that follows.
Summer tire or all season tire (→ P. 4 1 9 )
An all season tire has “M+S” on the sidewall. A tire not marked “M+S” is a
summer tire.
“TEMPORARY USE ONLY” (→ P. 4 9 6 )
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.

545
6-1. Specifications
6
Vehicle specifications
IS350/250_U■
DOT quality grades
All passenger vehicle tires must conform to Federal Safety Require-
ments 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 gov-
ernment 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 sign ificantly from the norm due to varia-
tions in driving habits, service practices and differences in road characteris-
tics 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) trac-
tion.

546
6-1. Specifications
IS350/250_U■
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 fail-
ure.
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.
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

559
6
Vehicle specifications
IS350/250_U
6-3. Initialization
Items to initialize
ItemWhen to initializeReference
Maintenance data
(U.S.A. only)After the maintenance is performedP. 3 8 6
Tire pressure warning
system
• When rotating the tires with differing front and rear tire inflation pressures.
• When changing the tire inflation pressure by changing traveling
speed.
• When changing the tire size.
P. 4 1 3
The following items must be initialized for normal system operation in cases
such as after the battery is reconnected, or maintenance is performed on
the vehicle.

587
Alphabetical index
IS350/250_U
Tire informationGlossary ................................................ 546
Size ........................................................... 543
Tire identification number ............. 543
Uniform tire quality grading......... 544
Tires
Chains ..................................................... 206
Checking ................................................. 412
If you have a flat tire.......................... 492
Inflation pressure ................................424
Inflation pressure sensor.................. 414
Information..............................................541
Replacing............................................... 492
Rotating tires .......................................... 412
Size ............................................................. 531
Snow tires.............................................. 206
Tools ...........................................................492
Total load capacity............................... 205
Towing Dinghy towing............................... 211, 212
Emergency towing ........................... 463
Trailer towing......................................... 210
TRAC .......................................................... 196
Traction control ...................................... 196
Transmission shift switches ................ 149
Trip meter..................................................158 Trunk
Extending trunk space ....................354
Opener ...................................................... 52
Trunk light
Trunk light ................................................. 53
Wattage ................................................. 536
Turn signal lights Replacing light bulbs ......................... 451
Switch........................................................ 154
Wattage ................................................. 536
USB port* .................................................... 260
Vanity lights Vanity lights .......................................... 337
Wattage ................................................. 536
Vanity mirrors ........................................ 337
VDIM .......................................................... 196
Vehicle dynamics integrated management ........................................ 196
Vehicle identification number .......... 521
Vehicle stability control....................... 196
Ventilators ...............................................348
Voice command switch* ...................298
VSC............................................................. 196
U
V
*: For vehicles with a navigation system, refer to the “Navigation System Owner’s Manual”.