tire size Lexus IS250C 2010 User Guide

421
4-3. Do-it-yourself maintenance
4
Maintenance and care
10_IS250C/350C_U
CAUTION
■When replacing wheels
●Do not use wheels that are a different size from those recommended in the
Owner’s Manual, as this may result in loss of handling control.
●Never use an inner tube in a leaking wheel which is designed for a tubeless tire.
Doing so may result in an accident, causing death or serious injury.
NOTICE
■Replacing tire inflation pressure warning valves and transmitters
●Because tire repair or replacement may affect the tire pressure warning valves
and transmitters, make sure to have tires serviced by your Lexus dealer or other
qualified service shop. In addition, make sure to purchase your tire pressure
warning valves and transmitters at your Lexus dealer.
●Ensure that only genuine Lexus wheels are used on your vehicle.
Tire pressure warning valves and transmitters may not work properly with non-
genuine wheels.

470
5-2. Steps to take in an emergency
10_IS250C/350C_U
CAUTION
■Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly when cold
and inflated to the inflation pressure recommended by the vehicle manufacturer on
the vehicle placard or tire inflation pressure label (tire and loading information
label). (If your vehicle has tires of a different size than the size indicated on the vehi-
cle placard or tire inflation pressure label [tire and loading information label], you
should determine the proper tire inflation pressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire pressure
monitoring system (TPMS-tire pressure warning system) that illuminates a low tire
pressure telltale (tire pressure warning light) when one or more of your tires is sig-
nificantly under-inflated. Accordingly, when the low tire pressure telltale (tire pres-
sure warning light) illuminates, you should stop and check your tires as soon as
possible, and inflate them to the proper pressure. Driving on a significantly under-
inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation
also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling
and stopping ability.
Please note that the TPMS (tire pressure warning system) is not a substitute for
proper tire maintenance, and it is the driver's responsibility to maintain correct tire
pressure, even if under-inflation has not reached the level to trigger illumination of
the TPMS low tire pressure telltale (tire pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warning system)
malfunction indicator to indicate when the system is not operating properly. The
TPMS (tire pressure warning system) malfunction indicator is combined with the
low tire pressure telltale (tire pressure warning light). When the system detects a
malfunction, the telltale will flash for approximately one minute and then remain
continuously illuminated. This sequence will continue upon subsequent vehicle
start-ups as long as the malfunction exists. When the malfunction indicator is illumi-
nated, the system may not be able to detect or signal low tire pressure as intended.
TPMS (tire pressure warning system) malfunctions may occur for a variety of rea-
sons, including the installation of replacement or alternate tires or wheels on the
vehicle that prevent the TPMS (tire pressure warning system) from functioning
properly. Always check the TPMS (tire pressure warning system) malfunction tell-
tale after replacing one or more tires or wheels on your vehicle to ensure that the
replacement or alternate tires and wheels allow the TPMS (tire pressure warning
system) to continue to function properly.

536
6-1. Specifications
10_IS250C/350C_U
Steering
Tires and wheels
Ty p e A
Free playLess than 1.2 in. (30 mm)
Ti r e s i z e225/45R17 90W, 245/45R17 95W, T125/
70D17 98M (spare)
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)*
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 4.5 psi (30 kPa, 0.3
kgf/cm
2 or bar) to the front tires and rear
tires. Never exceed the maximum cold tire
inflation pressure indicated on the tire side-
wall.
Wheel size17 × 8J, 17 × 4T (spare)
Wheel nut torque76 ft•lbf (103 N•m, 10.5 kgf•m)

537
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_UType B
Ti r e s i z e
Front tires: 225/45R17 91V
Rear tires: 245/45R17 95V
Spare tire: T125/70D17 98M
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)*
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 side-
wall.
Wheel size17 × 8J, 17 × 4T (spare)
Wheel nut torque76 ft•lbf (103 N•m, 10.5 kgf•m)

538
6-1. Specifications
10_IS250C/350C_UTy p e C
Ti r e s i z e
Front tires: 225/40R18 88Y
Rear tires: 255/40R18 95Y
Spare tire: T145/70D17 106M
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)*
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 side-
wall.
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)

539
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_UType D
Ti r e s i z e
Front tires: 225/40R18 88W
Rear tires: 255/40R18 95W
Spare tire: T145/70D17 106M
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)*
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 side-
wall.
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)

540
6-1. Specifications
10_IS250C/350C_UTy p e E
Ti r e s i z eFront tires: 225/40RF18 88V
Rear tires: 255/40RF18 95V
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 11.7 psi (80 kPa,
0.8 kgf/cm
2 or bar) to the front tires and rear
tires. Never exceed the maximum cold tire
inflation pressure indicated on the tire side-
wall.
Wheel sizeFront wheels: 18 × 8J
Rear wheels: 18 × 8 1 /2J
Wheel nut torque76 ft•lbf (103 N•m, 10.5 kgf•m)

545
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_U
Tire information
Ty p i c a l t i r e s y m b o l s
Standard tire
Compact spare tire
Tire size(→ P. 547)
DOT and Tire Identification Number (TIN) (→P. 547)
Location of treadwear indicators (→ P. 4 0 6 )
Tire ply composition and materials
Plies are layers of rubber-coated parallel cords. Cords are the strands
which form the plies in a tire.

547
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_U
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 si ze 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)

551
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_U
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