2020 INFINITI QX50 tire size

The brake system has two separate hydraulic
circuits. If one circuit malfunctions, you will
still have braking at two wheels.
BRAKE PRECAUTIONS
Vacuum assisted brakes
The brake booster aids braking by using en-
gine vacuum. If the engine stops, you can
stop the vehicle by depressing the brake
pedal. However, greater foot pressure on the
brake pedal will be required to stop the ve-
hicle and stopping distance will be longer.
Using the brakes
Avoid resting your foot on the brake pedal
while driving. This will overheat the brakes,
wear out the brake pads faster, and reduce
gas mileage.
To help reduce brake wear and to prevent the
brakes from overheating, reduce speed and
downshift to a lower gear before going down
a slope or long grade. Overheated brakes
may reduce braking performance and could
result in loss of vehicle control.
WARNING
∙ While driving on a slippery surface, becareful when braking, accelerating or
downshifting. Abrupt braking or acceler-
ating could cause the wheels to skid and
result in an accident.
∙ If the engine is not running or is turned off while driving, the power assist for the
brakes will not work. Braking will be
harder.
Wet brakes
When the vehicle is washed or driven through
water, the brakes may get wet. As a result,
your braking distance will be longer and the
vehicle may pull to one side during braking.
To dry the brakes, drive the vehicle at a safe
speed while lightly pressing the brake pedal
to heat up the brakes. Do this until the brakes
return to normal. Avoid driving the vehicle at
high speeds until the brakes function cor-
rectly.
Parking brake break-in
Break in the parking brake shoes whenever
the stopping effect of the parking brake is
weakened or whenever the parking brake
shoes and/or rotors are replaced, in order to
assure the best brake performance. This procedure is described in the INFINITI
Service Manual. It is recommended that you
visit an INFINITI retailer for this service.
ANTI-LOCK BRAKING SYSTEM
(ABS)
WARNING
∙ The ABS is a sophisticated device, but it
cannot prevent accidents resulting from
careless or dangerous driving techniques.
It can help maintain vehicle control dur-
ing braking on slippery surfaces. Remem-
ber that stopping distances on slippery
surfaces will be longer than on normal
surfaces even with ABS. Stopping dis-
tances 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 speci- fied size of tires on all four wheels.
BRAKE SYSTEM
5-180Starting and driving

– When installing a spare tire, make surethat it is the proper size and type as
specified on the Tire and Loading In-
formation label. For additional infor-
mation, refer to “Tire and Loading In-
formation label” in the “Technical and
consumer information” section of this
manual.
– For additional information, refer to “Wheels and tires” in the “Do-it-
yourself” section of this manual.
The 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
Anti-lock Braking System will operate to pre-
vent 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 distances.
Self-test feature
The Anti-lock Braking System (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 malfunction, it switches the ABS off
and illuminates the ABS warning light on the
instrument panel. The brake system then op-
erates normally but without anti-lock assis-
tance.
If the ABS warning light illuminates during
the self-test or while driving, have the vehicle
checked. It is recommended that you visit an
INFINITI retailer for this service.
Normal operation
The Anti-lock Braking System (ABS) operates
at speeds above3-6mph(5-10km/h). The
speed varies according to road conditions. 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 prop-
erly. However, the pulsation may indicate
that road conditions are hazardous and extra
care is required while driving.
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 driv-
er’s responsibility to stay alert, drive safely
and be in control of the vehicle at all times.
Starting and driving5-181

DRAINING OF COOLANT WATER
If the vehicle is to be left outside without
antifreeze, drain the cooling system, including
the engine block. Refill before operating the
vehicle. For additional information, refer to
“Changing engine coolant” in the “Do-it-
yourself” section of this manual.
TIRE EQUIPMENT
1. SUMMER tires have a tread designed toprovide superior performance on dry
pavement. However, the performance of
these tires will be substantially reduced
in snowy and icy conditions. If you oper-
ate 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 that you
visit an INFINITI retailer for the tire type,
size, speed rating and availability infor-
mation.
2. For additional traction on icy roads, studded tires may be used. However,
some U.S. states and Canadian prov-
inces prohibit their use. Check local,
state and provincial laws before install-
ing 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.
3. Tire chains may be used. For additional information, refer to “Tire chains” in the
“Do-it-yourself” section of this manual.
SPECIAL WINTER EQUIPMENT
It is recommended that the following items
be carried in the vehicle during winter:
∙ A scraper and stiff-bristled brush to re- move ice and snow from the windows
and wiper blades.
∙ A sturdy, flat board to be placed under the jack to give it firm support.
∙ A shovel to dig the vehicle out of snow- drifts.
∙ Extra washer fluid to refill the windshield-washer fluid reservoir.
DRIVING ON SNOW OR ICE
WARNING
∙ Wet ice (32°F, 0°C and freezing rain),very cold snow or ice can be slick and very
hard to drive on. The vehicle will have
much less traction or “grip” under these
conditions. Try to avoid driving on wet
ice until the road is salted or sanded.
∙ Whatever the condition, drive with cau- tion. Accelerate and slow down with
care. If accelerating or downshifting too
fast, the drive wheels will lose even more
traction.
∙ Allow more stopping distance under these conditions. Braking should be
started sooner than on dry pavement.
∙ Allow greater following distances on slippery roads.
∙ Watch for slippery spots (glare ice). These may appear on an otherwise clear
road in shaded areas. If a patch of ice is
seen ahead, brake before reaching it. Try
not to brake while on the ice, and avoid
any sudden steering maneuvers.
∙ Do not use the cruise control on slippery roads.
5-192Starting and driving

Tire and Loading Information label
1Seating capacity: The maximum
number of occupants that can be
seated in the vehicle.
2Original tire size: The size of the
tires originally installed on the ve-
hicle at the factory.
3Cold tire pressure: Inflate the tires
to this pressure when the tires are
cold. Tires are considered COLD
after the vehicle has been parked
for 3 or more hours, or driven less
than 1 mile (1.6 km) at moderate
speeds. The recommended cold
tire inflation is set by the manu-
facturer to provide the best bal-
ance of tire wear, vehicle handling,
driveability, tire noise, etc., up to
the vehicle’s GVWR.
4Tire size - refer to “Tire labeling” in
this section.
5Spare tire size.
6Vehicle load limit: Refer to “Ve-
hicle loading information” in the
“Technical and consumer informa-
tion” section of this manual.
LDI3172
Do-it-yourself8-27

Checking tire pressure
1. Remove the valve stem cap fromthe tire.
2. Press the pressure gauge squarely onto the valve stem. Do
not press too hard or force the
valve stem sideways, or air will
escape. If the hissing sound of air
escaping from the tire is heard
while checking the pressure, re-
position the gauge to eliminate
this leakage. 3. Remove the gauge.
4. Read the tire pressure on the
gauge stem and compare to the
specification shown on the Tire
and Loading Information label.
5.
Add air to the tire as needed. If too
much air is added, press the core of
the valve stem briefly with the tip
of the gauge stem to release pres-
sure. Recheck the pressure and
add or release air as needed.
6. Install the valve stem cap.
7. Check the pressure of all other tires, including the spare.
Size Cold Tire Infla-
tion Pressure
Front and Rear
Original Tire:
P235/55RF19 33 psi, 230 kPa
Front and Rear
Original Tire:
P255/45RF20 33 psi, 230 kPa
Spare Tire: none
TIRE LABELING
Federal law requires tire manufactur-
ers to place standardized information
on the sidewall of all tires. This infor-
mation identifies and describes the
fundamental characteristics of the tire
and also provides the Tire Identifica-
tion Number (TIN) for safety standard
certification. The TIN can be used to
identify the tire in case of a recall.
LDI0393ExampleWDI0394
8-28Do-it-yourself

1Tire size (example: P215/65R15
95H)
1. P: The “P” indicates the tire is de- signed for passenger vehicles (not
all tires have this information).
2. Three-digit number (215): This number gives the width in millime-
ters of the tire from sidewall edge
to sidewall edge. 3. Two-digit number (65): This num-
ber, known as the aspect ratio,
gives the tire’s ratio of height to
width.
4. R: The “R” stands for radial.
5. Two-digit number (15): This num- ber is the wheel or rim diameter in
inches. 6. Two- or three-digit number (95):
This number is the tire’s load in-
dex. It is a measurement of how
much weight each tire can sup-
port. You may not find this infor-
mation 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.
Example
WDI0395
Do-it-yourself8-29

2TIN (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 week and 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.
3Tire 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.
4Maximum permissible inflation
pressure
This number is the greatest amount of
air pressure that should be put in the
tire. Do not exceed the maximum per-
missible inflation pressure.
5Maximum 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.
6Term of “tubeless” or “tube type”
Indicates whether the tire requires an
inner tube (“tube type”) or not (“tube-
less”).
Example
LDI2786
8-30Do-it-yourself

7The word “radial”
The word “radial” is shown if the tire
has radial structure.
8Manufacturer 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 (i.e.,
Summer, All Season or Snow) and con-
struction. 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 originally specified by INFINITI could affect the
proper operation of the low tire pressure
warning system.
∙
Always use tires of the same type, size,
brand, construction and tread pattern on
all four wheels. Failure to do so may result
in a circumference difference between
tires on the front and rear axles which can
cause the Vehicle Dynamic Control (VDC)
system to malfunction resulting in per-
sonal injury or death, excessive tire wear
and may damage the transmission, trans-
fer case and differential gears.
∙ For additional information regarding tires, refer to “Important Tire Safety In-
formation” (US) or “Tire Safety Informa-
tion” (Canada) in the Warranty Informa-
tion Booklet.
All-Wheel Drive (AWD) models
CAUTION
∙ ONLY use spare tires specified for the AWD model.
If excessive tire wear is found, it is recom-
mended that all four tires be replaced with
tires of the same size, brand, construction
and tread pattern. The tire pressure and
wheel alignment should also be checked and
corrected as necessary. It is recommended
that you visit an INFINITI retailer for this
service.
All season tires
INFINITI specifies All Season tires on some
models to provide good performance all year,
including snowy and icy road conditions. All
Season tires are identified by ALL SEASON
and/or M&S on the tire sidewall. Snow tires
have better snow traction than All Season
tires and may be more appropriate in some
areas.
Do-it-yourself8-31