2021 INFINITI Q50 tire size

faces will be longer than on normal
surfaces even with ABS. Stopping
distances may also be longer on
rough, gravel or snow covered roads,
or if you are using tire chains. Always
maintain a safe distance from the
vehicle in front of you. Ultimately,
the driver is responsible for safety.
. Tire type and condition may also
affect braking effectiveness.
— When replacing tires, install the specified size of tires on all four
wheels.
— When installing a spare tire, make sure that it is the proper size and
type as specified on the Tire and
Loading Information label. See
“Tire and loading information la-
bel” (P.10-13) of this manual.
— For detailed information, see “Wheels and tires” (P.8-25) of
this manual.
The Anti-lock Braking System (ABS) controls
the brakes so the wheels do not lock during
hard braking or when braking on slippery
surfaces. The system detects the rotation
speed at each wheel and varies the brake
fluid pressure to prevent each wheel from
locking and sliding. By preventing each wheel from locking, the system helps the
driver maintain steering control and helps to
minimize swerving and spinning on slippery
surfaces.
Using the system
Depress the brake pedal and hold it down.
Depress the brake pedal with firm steady
pressure, but do not pump the brakes. The
ABS will operate to prevent the wheels from
locking up. Steer the vehicle to avoid
obstacles.
WARNING
Do not pump the brake pedal. Doing so
may result in increased stopping dis-
tances.
Self-test feature
The ABS includes electronic sensors, electric
pumps, hydraulic solenoids and a computer.
The computer has a built-in diagnostic
feature that tests the system each time you
start the engine and move the vehicle at a
low speed in forward or reverse. When the
self-test occurs, you may hear a “clunk”
noise and/or feel a pulsation in the brake
pedal. This is normal and does not indicate a
malfunction. If the computer senses a mal-function, it switches the ABS off and
illuminates the ABS warning light on the
instrument panel. The brake system then
operates normally, but without anti-lock
assistance.
If the ABS warning light illuminates during
the self-test or while driving, have the
vehicle checked. It is recommended you visit
an INFINITI retailer for this service.
Normal operation
The ABS operates at speeds above 3 to 6
MPH (5 to 10 km/h).
When the ABS senses that one or more
wheels are close to locking up, the actuator
rapidly applies and releases hydraulic pres-
sure. This action is similar to pumping the
brakes very quickly. You may feel a pulsation
in the brake pedal and hear a noise from
under the hood or feel a vibration from the
actuator when it is operating. This is normal
and indicates that the ABS is operating
properly. However, the pulsation may indi-
cate that road conditions are hazardous and
extra care is required while driving.
Starting and driving5-127

5-134Starting and driving
SONAR INDICATOR
When the corner of the vehicle moves closer
to an object, the corner sensor indicator
appears on the upper display.
When the center of the vehicle moves close
to an object, the center sensor indicator
appears on the upper display.
FREEING A FROZEN DOOR LOCK
To prevent a door lock from freezing, apply
deicer through the key hole. If the lock
becomes frozen, heat the key before insert-
ing it into the key hole or use the Intelligent
Key system.
ANTIFREEZE
In the winter when it is anticipated that the
outside temperature will drop below 32°F
(0°C), check antifreeze to assure proper
winter protection. For additional informa-
tion, see “Engine cooling system” (P.8-3) or
“Intercooler cooling system” (P.8-5).
BATTERY
If the battery is not fully charged during
extremely cold weather conditions, the bat-
tery fluid may freeze and damage the
battery. To maintain maximum efficiency,
the battery should be checked regularly. For
additional information, see “Battery” (P.8-
11).
DRAINING OF COOLANT WATER
If the vehicle is to be left outside without
antifreeze, drain the cooling system, includ-
ing the engine block. Refill before operating
the vehicle. For details, see “Engine cooling
system” (P.8-3).
TIRE EQUIPMENT
SUMMER tires have a tread designed to
provide superior performance on dry pave-
ment. However, the performance of these
tires will be substantially reduced in snowy
and icy conditions. If you operate your
vehicle on snowy or icy roads, INFINITI
recommends the use of MUD & SNOW or
ALL SEASON tires on all four wheels. It is
recommended you consult an INFINITI re-
tailer for the tire type, size, speed rating and
availability information.
For additional traction on icy roads, studded
tires may be used. However, some U.S.
states and Canadian provinces prohibit their
use. Check local, state and provincial laws
before installing studded tires.
Skid and traction capabilities of studded
snow tires, on wet or dry surfaces, may be
poorer than that of non-studded snow tires.
Tire chains may be used. For details, see
“Tire chains” (P.8-33) of this manual.
Intelligent All-Wheel Drive (AWD)
models
If you install snow tires, they must also be
the same size, brand, construction and tread
pattern on all four wheels.
COLD WEATHER DRIVING

SDI2567
Tire and Loading Information label
Seating capacity: The maximum
number of occupants that can be
seated in the vehicle.
Vehicle load limit: See “Vehicle
loading information” (P.10-17).
Original size: The size of the tires
originally installed on the vehicle
at the factory.
Cold tire pressure: Inflate the
tires to this pressure when the
tires are cold. Tires are consid-
ered COLD after the vehicle hasbeen parked for 3 or more hours,
or driven less than 1 mile (1.6 km)
at moderate speeds. The recom-
mended cold tire inflation is set
by the manufacturer to provide
the best balance of tire wear,
vehicle handling, driveability, tire
noise, etc., up to the vehicle’s
GVWR.
Tire size — see “Tire labeling”
(P.8-29).
Spare tire size or compact spare
tire size (if so equipped)
Do-it-yourself8-27

(P.8-28).)
SizeCold Tire In-
flation Pres- sure
Front Original Tire:
P225/55RF17 95V 35 psi, 240
kPa
Front Original Tire:
P225/50RF18 94V 35 psi, 240
kPa
Front Original Tire:
P245/40RF19 94V 35 psi, 240
kPa
Front Original Tire:
245/40RF19 94W 35 psi, 240
kPa
Rear Original Tire:
P225/55RF17 95V 35 psi, 240
kPa
Rear Original Tire:
P225/50RF18 94V 35 psi, 240
kPa
Rear Original Tire:
P245/40RF19 94V 35 psi, 240
kPa
Rear Original Tire:
245/40RF19 94W 35 psi, 240
kPa
Rear Original Tire:
265/35RF19 94W 35 psi, 240
kPa
Recommended tire inflation pressures
at speeds of 100 MPH (160 km/h) or
higher where it is legal to do so.
SizeCold Tire In-
flation Pres- sure
Front Original Tire:
P225/55RF17 95V 38 psi, 260
kPa
Front Original Tire:
P225/50RF18 94V 41 psi, 280
kPa
Front Original Tire:
P245/40RF19 94V 42 psi, 290
kPa
Front Original Tire:
245/40RF19 94W 42 psi, 290
kPa
Rear Original Tire:
P225/55RF17 95V 38 psi, 260
kPa
Rear Original Tire:
P225/50RF18 94V 41 psi, 280
kPa
Rear Original Tire:
P245/40RF19 94V 42 psi, 290
kPa
Rear Original Tire:
245/40RF19 94W 42 psi, 290
kPa
Rear Original Tire:
265/35RF19 94W 42 psi, 290
kPa
SDI1575
Example
TIRE LABELING
Federal law requires tire manufac-
turers to place standardized informa-
tion on the sidewall of all tires. This
information identifies and describes
the fundamental characteristics of
the tire and also provides the tire
identification number (TIN) for safety
standard certification. The TIN can be
used to identify the tire in case of a
recall.
Do-it-yourself8-29

8-30Do-it-yourself
SDI1606
Example
Tire size (example: P215/60R16
94H)
1. P: The “P” indicates the tire is designed for passenger vehicles.
(Not all tires have this informa-
tion.)
2. Three-digit number (215): This number gives the width in milli-
meters of the tire from sidewall
edge to sidewall edge.
3. Two-digit number (60): This num- ber, known as the aspect ratio,
gives the tire’s ratio of height to width.
4. R: The “R” stands for radial. F: The “F” after “R” indicates Self-
Supporting type run-flat tire.
5. Two-digit number (16): This num- ber is the wheel or rim diameter in
inches.
6. Two- or three-digit number (94): This number is the tire’s load index.
It is a measurement of how much
weight each tire can support. You
may not find this information on all
tires because it is not required by
law.
7. H: Tire speed rating. You should not drive the vehicle faster than
the tire speed rating.
JVM0694X
Example
TIN (Tire Identification Number) for
a new tire (example: DOT XX XX XXX
XXXX)
1. DOT: Abbreviation for the “De- partment of Transportation”. The
symbol can be placed above, be-
low or to the left or right of the
Tire Identification Number.
2. Two-digit code: Manufacturer’s identification mark
3. Two-digit code: Tire size
4. Three-digit code: Tire type code (Optional)

5. Four numbers represent the weekand year the tire was built. For
example, the numbers 3103
means the 31st week of 2003. If
these numbers are missing, then
look on the other sidewall of the
tire.
Tire ply composition and material
The number of layers or plies of
rubber-coated fabric in the tire.
Tire manufacturers also must indicate
the materials in the tire, which include
steel, nylon, polyester, and others.
Maximum permissible inflation
pressure
This number is the greatest amount of
air pressure that should be put in the
tire. Do not exceed the maximum
permissible inflation pressure.
Maximum load rating
This number indicates the maximum
load in kilograms and pounds that can
be carried by the tire. When replacing
the tires on the vehicle, always use a
tire that has the same load rating as
the factory installed tire.
Term of “tubeless” or “tube type”
Indicates whether the tire requires an
inner tube (“tube type”) or not (“tube-
less”).
The word “radial”
The word “radial” is shown, if the tire
has radial structure.
Manufacturer or brand name
Manufacturer or brand name is
shown.
Other tire-related terminology:
In addition to the many terms that are
defined throughout this section, In-
tended Outboard Sidewall is (1) the
sidewall that contains a whitewall,
bears white lettering or bears manu-
facturer, brand and/or model name
molding that is higher or deeper than
the same molding on the other side-
wall of the tire, or (2) the outward
facing sidewall of an asymmetrical
tire that has a particular side that
must always face outward when
mounted on a vehicle.
TYPES OF TIRES
WARNING
. When changing or replacing tires, be
sure all four tires are of the same type
(Example: Summer, All Season or
Snow) and construction. An INFINITI
retailer may be able to help you with
information about tire type, size,
speed rating and availability.
. Replacement tires may have a lower
speed rating than the factory
equipped tires, and may not match
the potential maximum vehicle speed.
Never exceed the maximum speed
rating of the tire.
. Replacing tires with those not origin-
ally specified by INFINITI could affect
the proper operation of the TPMS.
. For additional information regarding
tires, refer to “Important Tire Safety
Information” (US) or “Tire Safety
Information” (Canada) in the War-
ranty Information Booklet.
All season tires
INFINITI specifies all season tires on some
models to provide good performance all
Do-it-yourself8-31

8-32Do-it-yourself
year, including snowy and icy road condi-
tions. All Season tires are identified by ALL
SEASON and/or M&S (Mud and Snow) on
the tire sidewall. Snow tires have better
snow traction than All Season tires and may
be more appropriate in some areas.
Summer tires
INFINITI specifies summer tires on some
models to provide superior performance on
dry roads. Summer tire performance is
substantially reduced in snow and ice. Sum-
mer tires do not have the tire traction rating
M&S on the tire sidewall.
If you plan to operate your vehicle in snowy
or icy conditions, INFINITI recommends the
use of SNOW tires or ALL SEASON tires on
all four wheels.
Snow tires
If snow tires are needed, it is necessary to
select tires equivalent in size and load rating
to the original equipment tires. If you do not,
it can adversely affect the safety and
handling of your vehicle.
Generally, snow tires will have lower speed
ratings than factory equipped tires and may
not match the potential maximum vehicle
speed. Never exceed the maximum speed
rating of the tire.
If you install snow tires, they must be thesame size, brand, construction and tread
pattern on all four wheels.
For additional traction on icy roads, studded
tires may be used. However, some U.S.
states and Canadian provinces prohibit their
use. Check local, state and provincial laws
before installing studded tires. Skid and
traction capabilities of studded snow tires,
on wet or dry surfaces, may be poorer than
that of non-studded snow tires.
Run-flat tires (if so equipped)
Your vehicle is equipped with run-flat tires.
You can continue driving to a safe location
even if they are punctured. Always use run-
flat tires of the specified size on all four
wheels. Mixing tire sizes or construction may
reduce vehicle handling stability. If neces-
sary, contact an INFINITI retailer for assis-
tance.
Frequently check the tire pressure and adjust
pressure of each tire properly. The tire
pressure can be also checked in the vehicle
information display.
It can be difficult to tell if a run-flat tire is
under-inflated or flat. Check the tire pres-
sures as described earlier in this section. If
the tire becomes under-inflated while driv-
ing, the low tire pressure warning light will
illuminate. If the tire becomes flat while
driving, the low tire pressure warning light
and the “Flat Tire - Visit dealer” warning will
appear.
Low tire pressure:
If the vehicle is being driven with low tire
pressure, the low tire pressure warning light
will illuminate.
Flat tire:
If the vehicle is being driven with one or more
flat tires, the low tire pressure warning light
will illuminate continuously and a chime will
sound for 10 seconds. A “Flat Tire - Visit
dealer” warning also appears in the vehicle
information display.
The chime will only sound at the first
indication of a flat tire and the warning light
will illuminate continuously. When the flat
tire warning is activated, have the system
reset and the tire checked, and replaced if
necessary. It is recommended you visit an
INFINITI retailer for these services. Even if
the tire is inflated to the specified COLD tire
pressure, the warning light will continue to
illuminate until the system is reset by an
INFINITI retailer.
If the low tire pressure warning light illumi-
nates continuously and the “Flat Tire - Visit
dealer” warning appears in the vehicle
information display:
. Do not exceed 50 MPH (80 km/h).

.Increase your following distance to allow
for increased stopping distances.
. Avoid sudden maneuvers, hard cornering
and hard braking.
WARNING
. Although you can continue driving
with a punctured run-flat tire, re-
member that vehicle handling stabi-
lity is reduced, which could lead to an
accident and personal injury. Also,
driving a long distance at high speeds
may damage the tire.
. Do not drive at speeds above 50
MPH (80 km/h) and do not drive
more than approximately 93 miles
(150 km) with a punctured run-flat
tire. The actual distance the vehicle
can be driven on a flat tire depends on
outside temperature, vehicle load,
road conditions and other factors.
. Drive safely at reduced speeds. Avoid
hard cornering or braking, which may
cause you to lose control of the
vehicle.
. If you detect any unusual sounds or
vibrations while driving with a punc-
tured run-flat tire, pull off the road
to a safe location and stop the vehicle as soon as possible. The tire may be
seriously damaged and need to be
replaced.
CAUTION
.
Never install tire chains on a punctu-
red run-flat tire, as this could damage
your vehicle.
. Avoid driving over any projection or
pothole, as the clearance between
the vehicle and the ground is smaller
than normal.
. Do not enter an automated car wash
with a punctured run-flat tire.
. It is recommended you have the
punctured tire inspected by an
INFINITI retailer or other authorized
repair shop. Replace the tire as soon
as possible if the tire is seriously
damaged.
TIRE CHAINS
CAUTION
Tire chains/cables should not be in-
stalled on 265/35RF19 tires. Doing so
will cause damage to the vehicle. If you
plan to use tire chains/cables, you
should install 245/40RF19 tires on your
vehicle.
Use of tire chains may be prohibited accord-
ing to location. Check the local laws before
installing tire chains. When installing tire
chains, make sure they are the proper size
for the tires on your vehicle and are installed
according to the chain manufacturer’s sug-
gestions. Use only SAE Class S chains. Class
“S” chains are used on vehicles with re-
stricted tire to vehicle clearance. Vehicles
that can use Class “S” chains are designed to
meet the SAE standard minimum clearances
between the tire and the closest vehicle
suspension or body component required to
accommodate the use of a winter traction
device (tire chains or cables). The minimum
clearances are determined using the factory
equipped tire size. Other types may damage
your vehicle. Use chain tensioners when
recommended by the tire chain manufac-
turer to ensure a tight fit. Loose end links of
Do-it-yourself8-33