2018 INFINITI Q50 tire size

1-20Safety — Seats, seat belts and supplemental restraint system
SSS0294A
Shoulder belt height adjustment
(front seats)
The shoulder belt anchor height should be
adjusted to the position best for you. (See
“Precautions on seat belt usage” (P.1-12).)
To adjust, push the button
, and then move
the shoulder belt anchor to the desired
position, so that the belt passes over the
center of the shoulder. The belt should be
away from your face and neck, but not
falling off of your shoulder. Release the
adjustment button to lock the shoulder belt
anchor into position.
WARNING
. After adjustment, release the adjust-
ment button and try to move the
shoulder belt anchor up and down to
make sure it is securely fixed in
position.
. The shoulder belt anchor height
should be adjusted to the position
best for you. Failure to do so may
reduce the effectiveness of the entire
restraint system and increase the
chance or severity of injury in an
accident.
SEAT BELT EXTENDERS
If, because of body size or driving position, it
is not possible to properly fit the lap-
shoulder belt and fasten it, an extender that
is compatible with the installed seat belts is
available that can be purchased. The ex-
tender adds approximately 8 in (200 mm) of
length and may be used for either the driver
or front passenger seating position. It is
recommended you visit an INFINITI retailer
for assistance with purchasing an extender if
an extender is required.
WARNING
.It is recommended only INFINITI seat
belt extenders, made by the same
company which made the original
equipment seat belts, be used with
the INFINITI seat belts.
. Adults and children who can use the
standard seat belt should not use an
extender. Such unnecessary use could
result in serious personal injury in the
event of an accident.
. Never use seat belt extenders to
install child restraints. If the child
restraint is not secured properly, the
child could be seriously injured or
killed in a collision or a sudden stop.
SEAT BELT MAINTENANCE
.To clean the seat belt webbing, apply a
mild soap solution or any solution re-
commended for cleaning upholstery or
carpets. Then, wipe with a cloth and
allow the seat belts to dry in the shade.
Do not allow the seat belts to retract
until they are completely dry.
. If dirt builds up in the shoulder belt guide
of the seat belt anchors, the seat belts
may retract slowly. Wipe the shoulder

belt guide with a clean, dry cloth.
. Periodically check to see that the seat
belt and the metal components such as
buckles, tongues, retractors, flexible
wires and anchors work properly. If loose
parts, deterioration, cuts or other da-
mage on the webbing is found, the entire
seat belt assembly should be replaced.
JVR0256X
Models with rear seat folding
WARNING
Do not allow children to play with the
seat belts. Most seating positions are
equipped with Automatic Locking Re-
tractor (ALR) mode seat belts. If the seat
belt becomes wrapped around a child’s
neck with the ALR mode activated, the
child can be seriously injured or killed if
the seat belt retracts and becomes tight.
This can occur even if the vehicle is
parked. Unbuckle the seat belt to release
the child. For the center of the rear seat
on the models with rear seat folding, the
connector tongue
may also be re- leased. Release the connector tongue by
inserting a suitable tool (such as a key)
into the connector buckle
. If the seat
belt can not be unbuckled or is already
unbuckled, release the child by cutting
the seat belt with a suitable tool (such as
a knife or scissors) to release the seat
belt.
Children need adults to help protect them.
They need to be properly restrained.
In addition to the general information in this
manual, child safety information is available
from many other sources, including doctors,
teachers, government traffic safety offices,
and community organizations. Every child is
different, so be sure to learn the best way to
transport your child.
There are three basic types of child restraint
systems:
. Rear-facing child restraint
. Forward-facing child restraint
. Booster seat
The proper restraint depends on the child’s
size. Generally, infants up to about 1 year
and less than 20 lbs (9 kg) should be placed
in rear-facing child restraints. Forward-
facing child restraints are available for
children who outgrow rear-facing child re-
straints and are at least 1 year old. Booster
Safety — Seats, seat belts and supplemental restraint system1-21
CHILD SAFETY

WARNING
.Radio waves could adversely affect
electric medical equipment. Those
who use a pacemaker should contact
the electric medical equipment man-
ufacturer for the possible influences
before use.
. If the light does not illuminate with
the ignition switch pushed ON, have
the vehicle checked as soon as possi-
ble. It is recommended you visit an
INFINITI retailer for this service.
. If the light illuminates while driving,
avoid sudden steering maneuvers or
abrupt braking, reduce vehicle speed,
pull off the road to a safe location
and stop the vehicle as soon as
possible. Driving with under-inflated
tires may permanently damage the
tires and increase the likelihood of
tire failure. Serious vehicle damage
could occur and may lead to an
accident and could result in serious
personal injury. Check the tire pres-
sure for all four tires. Adjust the tire
pressure to the recommended COLD
tire pressure shown on the Tire and
Loading Information label to turn the
low tire pressure warning light OFF.
If the light still illuminates while driving after adjusting the tire pres-
sure, a tire may be flat or the TPMS
may be malfunctioning. If you have a
flat tire, replace it with a spare tire (if
so equipped) as soon as possible. If no
tire is flat and all tires are properly
inflated, it is recommended you con-
sult an INFINITI retailer.
. For models with run-flat tires,
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 tires.
— 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.
— If you detect any unusual sounds or vibrations while driving with a
punctured run-flat tire, pull off
the road to a safe location and
stop the vehicle as soon as possi-
ble. The tire may be seriously damaged and need to be replaced.
. Since the spare tire is not equipped
with the TPMS, when a spare tire is
mounted or a wheel is replaced, the
TPMS will not function and the low
tire pressure warning light will flash
for approximately 1 minute. The light
will remain on after the 1 minute.
Have your tires replaced and/or
TPMS system reset as soon as pos-
sible. It is recommended you visit an
INFINITI retailer for these services.
. Replacing tires with those not origin-
ally specified by INFINITI could affect
the proper operation of the TPMS.
CAUTION
.The TPMS is not a substitute for the
regular tire pressure check. Be sure to
check the tire pressure regularly.
. If the vehicle is being driven at speeds
of less than 16 MPH (25 km/h), the
TPMS may not operate correctly.
. Be sure to install the specified size of
tires to the four wheels correctly.
Instruments and controls2-13

THREE-WAY CATALYST
The three-way catalyst is an emission con-
trol device installed in the exhaust system.
Exhaust gases in the three-way catalyst are
burned at high temperatures to help reduce
pollutants.
WARNING
.The exhaust gas and the exhaust
system are very hot. Keep people,
animals or flammable materials away
from the exhaust system compo-
nents.
. Do not stop or park the vehicle over
flammable materials such as dry
grass, waste paper or rags. They
may ignite and cause a fire.
CAUTION
.Do not use leaded gasoline. Deposits
from leaded gasoline seriously reduce
the three-way catalyst’s ability to
help reduce exhaust pollutants.
. Keep your engine tuned up. Malfunc-
tions in the ignition, fuel injection, or
electrical systems can cause overrich fuel flow into the three-way catalyst,
causing it to overheat. Do not keep
driving if the engine misfires, or if
noticeable loss of performance or
other unusual operating conditions
are detected. Have the vehicle in-
spected promptly. It is recommended
you visit an INFINITI retailer for this
service.
. Avoid driving with an extremely low
fuel level. Running out of fuel could
cause the engine to misfire, damaging
the three-way catalyst.
. Do not race the engine while warming
it up.
. Do not push or tow your vehicle to
start the engine.
TIRE PRESSURE MONITORING
SYSTEM (TPMS)
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
vehicle placard or tire inflation pressure
label. (If your vehicle has tires of a different
size than the size indicated on the vehicle
placard or tire inflation pressure 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 Mon-
itoring System (TPMS) that illuminates a low
tire pressure telltale when one or more of
your tires is significantly under-inflated.
Accordingly, when the low tire pressure
telltale 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.
For models with run-flat tires, 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. The flat tire warning
will also appear 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, it is recommended
you have the system reset and the tire
checked and replaced if necessary by an
INFINITI retailer. 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.
Your vehicle can be driven for a limited time
on a flat tire. See “Run-flat tires” (P.8-39).
Starting and driving5-5

5-10Starting and driving
damage. See “Wheels and tires” (P.8-32) of
this manual.
If a tire rapidly loses air pressure or “blows-
out” while driving maintain control of the
vehicle by following the procedure below.
Please note that this procedure is only a
general guide. The vehicle must be driven as
appropriate based on the conditions of the
vehicle, road and traffic.
WARNING
The following actions can increase the
chance of losing control of the vehicle if
there is a sudden loss of tire air pressure.
Losing control of the vehicle may cause a
collision and result in personal injury.
.The vehicle generally moves or pulls
in the direction of the flat tire.
. Do not rapidly apply the brakes.
. Do not rapidly release the accelerator
pedal.
. Do not rapidly turn the steering
wheel.
1. Remain calm and do not overreact.
2. Maintain a firm grip on the steering wheel with both hands and try to hold
a straight course. 3. When appropriate, slowly release the
accelerator pedal to gradually slow the
vehicle.
4. Gradually steer the vehicle to a safe location off the road and away from
traffic if possible.
5. Lightly apply the brake pedal to gradu- ally stop the vehicle.
6. Turn on the hazard warning flashers and either contact a roadside emergency
service to change the tire or see “Chan-
ging a flat tire” (P.6-4) of this Owner’s
Manual.
DRINKING ALCOHOL/DRUGS
AND DRIVING
WARNING
Never drive under the influence of alco-
hol or drugs. Alcohol in the bloodstream
reduces coordination, delays reaction
time and impairs judgement. Driving
after drinking alcohol increases the like-
lihood of being involved in an accident
injuring yourself and others. Addition-
ally, if you are injured in an accident,
alcohol can increase the severity of the
injury. INFINITI is committed to safe driving. How-
ever, you must choose not to drive under the
influence of alcohol. Every year thousands of
people are injured or killed in alcohol-related
accidents. Although the local laws vary on
what is considered to be legally intoxicated,
the fact is that alcohol affects all people
differently and most people underestimate
the effects of alcohol.
Remember, drinking and driving don’t mix!
And that is true for drugs, too (over-the-
counter, prescription, and illegal drugs).
Don’t drive if your ability to operate your
vehicle is impaired by alcohol, drugs, or some
other physical condition.
INTELLIGENT ALL-WHEEL
DRIVE (AWD) DRIVING SAFETY
PRECAUTIONS (AWD models)
WARNING
.
Do not drive beyond the performance
capability of the tires, even with
Intelligent AWD engaged. Accelerat-
ing quickly, sharp steering maneuvers
or sudden braking may cause loss of
control.
. Always use tires of the same type,
size, brand, construction (bias, bias-

5-124Starting and driving
If any malfunction occurs in the Intelligent
All-Wheel Drive (AWD) system while the
engine is running, warning messages appear
in the vehicle information display.
JVS0228M
If the “AWD Error” warningappears, there
may be a malfunction in the Intelligent AWD
system. Reduce vehicle speed and have the
system checked as soon as possible. It is
recommended you visit an INFINITI retailer
for this service.
The “AWD High Temp.” (high temperature)
warning
may appear while trying to free a stuck vehicle due to increased oil tempera-
ture. The driving mode may change to Two-
Wheel Drive (2WD). If this warning is
displayed, stop the vehicle with the engine
idling, as soon as it is safe to do so. Then if
the warning turns off, you can continue
driving.
The “Tire Size Incorrect” warning
may
appear if there is a large difference between
the diameters of front and rear wheels. Pull
off the road in a safe area, with the engine
idling. Check that all tire sizes are the same,
that the tire pressure is correct and that the
tires are not excessively worn.
If any warning message continues to be
displayed, have your vehicle checked as soon
as possible. It is recommended you visit an
INFINITI retailer for this service.
WARNING
. For AWD equipped vehicles, do not
attempt to raise two wheels off the
ground and shift the transmission to
any drive or reverse position with the
engine running. Doing so may result
in drivetrain damage or unexpected
vehicle movement which could result
in serious vehicle damage or personal
injury.
INTELLIGENT ALL-WHEEL
DRIVE (AWD) (if so equipped)

an INFINITI retailer for this service.BRAKE ASSIST
When the force applied to the brake pedal
exceeds a certain level, the Brake Assist is
activated generating greater braking force
than a conventional brake booster even with
light pedal force.
WARNING
The Brake Assist is only an aid to assist
braking operation and is not a collision
warning or avoidance device. It is the
driver’s responsibility to stay alert, drive
safely and be in control of the vehicle at
all times.
ANTI-LOCK BRAKING SYSTEM
(ABS)
WARNING
. The Anti-lock Braking System (ABS)
is a sophisticated device, but it
cannot prevent accidents resulting
from careless or dangerous driving
techniques. It can help maintain ve-
hicle control during braking on slip-
pery surfaces. Remember that
stopping distances on slippery sur- 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.10-16) of this manual.
— For detailed information, see “Wheels and tires” (P.8-32) 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
Starting and driving5-131
BRAKE ASSIST

automatically stopping during the same
journey.
. Whenever the Idling Stop System is
deactivated the indicator light
on the
Idling Stop OFF switch illuminates. In
this condition the Idling Stop System
cannot prevent unnecessary fuel con-
sumption, exhaust emissions, or noise
during your journey.
. If the Idling Stop System is malfunction-
ing, the indicator light
on the Idling
Stop OFF switch illuminates.
NOTE:
The Idling Stop System ON or OFF message
is displayed for a few seconds in the vehicle
information display when the Idling Stop
OFF switch is pushed. See “Idling Stop
System ON or OFF” (P.5-139).
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 (for
VR30DDTT engine models)” (P.8-6), “En-
gine cooling system (for 2.0L turbo gasoline
engine models)” (P.8-8) or “Intercooler cool-
ing system (for VR30DDTT engine models)”
(P.8-9).
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-
16).
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 (for VR30DDTT engine models)”
(P.8-6) or “Engine cooling system (for 2.0L
turbo gasoline engine models)” (P.8-8).
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.8-40) of this manual.
Starting and driving5-141
COLD WEATHER DRIVING