Lexus IS250C 2010 Owner's Manual
Page 551 of 586
550
6-1. Specifications
10_IS250C/350C_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. 139.
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 
Page 552 of 586
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 
Page 553 of 586
552
6-1. Specifications
10_IS250C/350C_U
Tire related termMeaning
Rim widthNominal distance between rim flanges
Vehicle maximum load on 
the tireThe load on an individual tire that is determined by 
distributing to each axle its share of the maximum 
loaded vehicle weight, and dividing by two
Vehicle normal load on 
the tire
The load on an individual tire that is determined by 
distributing to each axle its share of curb weight, 
accessory weight, and normal occupant weight (dis-
tributed in accordance with Table 1
* below), and 
dividing it by two
We a t h e r  s i d eThe surface area of the rim not covered by the 
inflated tire 
Page 554 of 586
553
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_U
Tire related termMeaning
Bead
The part of the tire that is made of steel wires, 
wrapped or reinforced by ply cords and that is 
shaped to fit the rim
Bead separationA breakdown of the bond between components in 
the bead
Bias ply tire
A pneumatic tire in which the ply cords that extend to 
the beads are laid at alternate angles substantially 
less than 90 degrees to the centerline of the tread
CarcassThe tire structure, except tread and sidewall rubber 
which, when inflated, bears the load
ChunkingThe breaking away of pieces of the tread or sidewall
CordThe strands forming the plies in the tire
Cord separationThe parting of cords from adjacent rubber com-
pounds
CrackingAny parting within the tread, sidewall, or innerliner of 
the tire extending to cord material
CT
A pneumatic tire with an inverted flange tire and rim 
system in which the rim is designed with rim flanges 
pointed radially inward and the tire is designed to fit 
on the underside of the rim in a manner that encloses 
the rim flanges inside the air cavity of the tire
Extra load tire
A tire designed to operate at higher loads and at 
higher inflation pressures than the corresponding 
standard tire
GrooveThe space between two adjacent tread ribs
InnerlinerThe layer(s) forming the inside surface of a tubeless 
tire that contains the inflating medium within the tire
Innerliner separationThe parting of the innerliner from cord material in the 
carcass 
Page 555 of 586
554
6-1. Specifications
10_IS250C/350C_U
Tire related termMeaning
Intended outboard side-
wall
(a) The sidewall that contains a whitewall, bears 
white lettering, or bears manufacturer, brand, 
and/or model name molding that is higher or 
deeper than the same molding on the other side-
wall of the tire, or
(b) The outward facing sidewall of an asymmetrical  tire that has a particular side that must always 
face outward when mounted on a vehicle
Light truck (LT) tire
A tire designated by its manufacturer as primarily 
intended for use on lightweight trucks or multipur-
pose passenger vehicles
Load ratingThe maximum load that a tire is rated to carry for a 
given inflation pressure
Maximum load ratingThe load rating for a tire at the maximum permissible 
inflation pressure for that tire
Maximum permissible 
inflation pressureThe maximum cold inflation pressure to which a tire 
may be inflated
Measuring rimThe rim on which a tire is fitted for physical dimension 
requirements
Open spliceAny parting at any junction of tread, sidewall, or 
innerliner that extends to cord material
Outer diameterThe overall diameter of an inflated new tire
Overall width
The linear distance between the exteriors of the side-
walls of an inflated tire, including elevations due to 
labeling, decorations, or protective bands or ribs
Passenger car tire
A tire intended for use on  passenger cars, multipur-
pose passenger vehicles, and trucks, that have a 
gross vehicle weight rating (GVWR) of 10000 lb. or 
less.
PlyA layer of rubber-coated parallel cords 
Page 556 of 586
555
6-1. Specifications
6
Vehicle specifications
10_IS250C/350C_U
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 materials, 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 
Page 557 of 586
556
6-1. Specifications
10_IS250C/350C_U
*: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
Tread separationPulling 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 
Page 558 of 586
557
6
Vehicle specifications
10_IS250C/350C_U
6-2. Customization
Customizable features
ItemFunctionDefault settingCustomizedsetting
Smart access 
system with 
push-button 
start 
(
→P.  2 8 )
Operation signal
(Emergency flashers)OnOff
Operation signal
(Buzzer)OnOff
Wireless 
remote con-
trol 
(
→P.  4 0 )
Unlocking operation
Driver's door 
unlocked in one 
step, both side 
doors unlocked 
in two steps
Both side doors 
unlocked in one  step
Automatic door lock 
function to be activated if 
door is not opened after 
being unlocked
OnOff
Your vehicle includes a variety of electr onic features that can be personal-
ized to your preferences. Programming these preferences requires spe-
cialized equipment and may be performed by an authorized Lexus
dealership.
Some function settings are changed simultaneously with other functions
being customized. Contact your Lexus dealer for further details. 
Page 559 of 586
558
6-2. Customization
10_IS250C/350C_U
Wi re le ss 
remote con-
trol 
(
→P.  4 0 )
Time elapsed before auto-
matic door lock function is 
activated if door is not 
opened after being 
unlocked
60 seconds
30 seconds
120 seconds
Operation signal
(Emergency flashers)OnOff
Operation signal 
(Buzzer) OnOff
Door lock buzzerOnOff
Trunk unlocking functionOnOff
Trunk unlocking operationPush and holdPush twice
One short push
Panic functionOnOff
ItemFunctionDefault settingCustomizedsetting 
Page 560 of 586
559
6-2. Customization
6
Vehicle specifications
10_IS250C/350C_U
Door lock 
(
→P.  4 3 )
Unlocking using a key
Driver's door 
unlocked in one 
step, both side 
doors unlocked 
in two steps
Both side doors 
unlocked in one  step
Speed-detecting auto-
matic door lock function 
(Manual transmissions)
OnOff
Speed-detecting auto-
matic door lock function 
(Automatic transmissions)
OffOn
Opening driver's door 
unlocks both side doors 
(Manual transmissions)
OnOff
Opening driver's door 
unlocks both side doors 
(Automatic transmissions)
OffOn
Shifting gears to P 
unlocks both side doorsOnOff
Shifting gears to position 
other than P locks both 
side doors
OnOff
Steering 
wheel 
(
→P.  7 2 )
Auto tilt-away functionOnOff
ItemFunctionDefault settingCustomizedsetting