2021 LEXUS IS300 Owners Manual

3858-1. Specifications
8
Vehicle specifications
Compact spare tireLocation of treadwear indicators ( P.303)
Load limit at maximum cold tire inflation pressure ( P.303)
Maximum cold tire inflation pressure ( P.379)
This means the pressure to which a tire may be inflated.
DOT and Tire Identification Number (TIN) ( P.385)
Tire ply composition and materials
Plies are layers of rubber-coated parallel cords. Cords are the strands which form the plies
in a tire.
“TEMPORARY USE ONLY”
A compact spare tire is identified by the phrase “TEMPORARY USE ONLY” molded on its
sidewall. This tire is designed for temporary emergency use only.
Tire size ( P.386)
TUBELESS or TUBE TYPE
A tubeless tire does not have a tube and air is directly put into the tire. A tube type tire has a
tube inside the tire and the tube maintains the air pressure.
Type A
A
B
C
D
E
F
G
H
Typical DOT and Tire Identifica-
tion Number (TIN)

3868-1. Specifications
DOT symbol*
Tire Identification Number (TIN)
Tire manufacturer’s identification
mark
Tire size code
Manufacturer’s optional tire type
code (3 or 4 letters)
Manufacturing week
Manufacturing year
*:The DOT symbol certifies that the tire
conforms to applicable Federal Motor
Vehicle Safety Standards.
Type B
DOT symbol
*
Tire Identification Number (TIN)
Tire manufacturer’s identification
mark
Manufacturer’s code
Manufacturing week
Manufacturing year
*:The DOT symbol cert ifies that the tire
conforms to applicable Federal Motor
Vehicle Safety Standards.
■Typical tire size information
The illustration indicates typical tire
size.
Tire use (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 digits or 3 digits)
Speed symbol (alphabet with one
letter)
■Tire dimensionsSection width
Tire height
A
B
C
D
E
F
G
A
B
C
D
E
F
Tire size
A
B
C
D
E
F
G
A
B

3878-1. Specifications
8
Vehicle specifications
Wheel diameter
Bead
Sidewall
Shoulder
Tread
Belt
Inner liner
Reinforcing rubber
Carcass
Rim lines
Bead wires
Chafer
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 pro-
spective 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 con-
form 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 condi-
tions 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.
Performance may differ significantly from
the norm due to variatio ns 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 con-
trolled conditions on specified govern-
ment 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
Tire section names
Uniform Tire Quality Grading
C
A
B
C
D
E
F
G
H
I
J
K

3888-1. Specifications
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 condi-
tions 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. Grade C corresponds to
a level of perfor-
mance which all passenger car tires must
meet under the Fede ral 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 of a tire
assume that it is properly inflated and not
overloaded.
Excessive speed, unde rinflation, or exces-
sive loading, either separately or in combi-
nation, can cause heat buildup and
possible tire failure.
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation pressure
Tire 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
Maximum inflation pressureThe maximum cold inflated pressure to which a tire
may be inflated, 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 replaced) of automatic trans-
mission, power steering, power brakes, power win-
dows, power 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 equip-
ment, including the maximum capacity of fuel, oil
and coolant, and if so equipped, air conditioning
and additional weight optional engine

3898-1. Specifications
8
Vehicle specifications
Maximum loaded vehicle weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant weight
150 lb. (68 kg) times the number of occupants
specified in the second column of Table 1
* that fol-
lows
Occupant distributionDistribution of occupants in a vehicle as specified in
the third column of Table 1
* below
Production options weight
The combined weight of installed regular produc-
tion options weighing over 5 lb. (2.3 kg) in excess of
the standard items which they replace, not previ-
ously considered in curb weight or accessory
weight, including heavy duty brakes, ride levelers,
roof rack, heavy duty battery, and special trim
RimA metal support for a tire or a tire and tube assem-
bly 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
Rim widthNominal distance between rim flanges
Vehicle capacity weight (Total load
capacity)The rated cargo and luggage load plus 150 lb. (68
kg) times the vehicle’s designated seating capacity
Vehicle maximum load on the tire
The load on an individual ti re 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 ti re that is determined by
distributing to each axle its share of curb weight,
accessory weight, and normal occupant weight
(distributed in accor dance with Table 1
* below), and
dividing by two
Weather sideThe surface area of the rim not covered by the
inflated tire
Tire related termMeaning

3908-1. Specifications
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 substan-
tially 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 operat e 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 in side 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
Tire related termMeaning

3918-1. Specifications
8
Vehicle specifications
Intended outboard sidewall
(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 sidewall
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 lightwe ight 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 permissi-
ble inflation pressure for that tire
Maximum permissible inflation pres-
sureThe maximum cold inflation pressure to which a tire
may be inflated
Measuring rimThe rim on which a tire is fitted for physical dimen-
sion 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
sidewalls 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 10,000 lb.
or less.
PlyA layer of rubber-c oated parallel cords
Ply separationA parting of rubber compound between adjacent
plies
Pneumatic tire
A mechanical device made of rubber, chemicals,
fabric 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
Tire related termMeaning

3928-1. Specifications
*: Table 1 -Occupant loading and distribution for vehicle normal load for various desig-nated seating capacities
Radial ply tire
A pneumatic tire in which the ply cords that extend
to the beads are laid at su bstantially 90 degrees to
the centerline of the tread
Reinforced tire
A tire designed to operat e at higher loads and at
higher inflation pressures than the corresponding
standard tire
Section width
The linear distance between the exteriors of the
sidewalls 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 Referenc e Test Tire, when using the snow
traction test as described in ASTM F-1805-00,
Standard Test Method fo r Single Wheel Driving
Traction in a Straight Line on Snow-and Ice-Cov-
ered Surfaces, and which is marked with an Alpine
Symbol ( ) on at least one sidewall
Test rimThe rim on which a tire is fitted for testing, and may
be any rim listed as appropriate for use with that tire
TreadThat portion of a tire that comes into contact with
the road
Tread ribA tread section running ci rcumferentially 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
Tire related termMeaning