2008 PONTIAC G8 tire size

Tire SizeRecommended Cold Tire Ination
Occupant and Cargo Weight: 573 lbs (260 kg) or Less Occupant and Cargo Weight:
Up to 917 lbs (416 kg)
(Vehicle Capacity Weight)
Front Tires Rear Tires Front Tires Rear Tires
P245/45R18 96V 35 psi (240 kPa) 35 psi (240 kPa) 39 psi (270 kPa) 44 psi (300 kPa) 245/45R18 96V 36 psi (250 kPa) 36 psi (250 kPa) 39 psi (270 kPa) 44 psi (300 kPa)
245/40R19 94W 36 psi (250 kPa) 36 psi (250 kPa) 39 psi (270 kPa) 44 psi (300 kPa)
When you end this high-speed
driving, return the tires to the cold tire
ination pressure shown on the Tire
and Loading Information label. See
Loading the Vehicle on page 8-28
and Inflation - Tire Pressure on
page 9-46 .
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your vehicle’s
tires and transmit tire pressure
readings to a receiver located in the
vehicle.
Each tire, including the spare (if
provided), should be checked
monthly when cold and inated to the
ination pressure recommended by
the vehicle manufacturer on the
vehicle placard or tire ination pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire ination pressure label, you
should determine the proper tire
ination pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low tire
pressure telltale when one or
more of your tires is signicantly
under-inated.
Vehicle Service and Care 9-49
2008 - Pontiac G8 Owner Manual

The TPMS operates on a radio
frequency and complies with
RSS-210 of Industry and Science
Canada. Operation is subject to the
following two conditions:
1. This device may not cause
interference.
2. This device must accept any
interference received, including
interference that may cause
undesired operation of the
device.
Changes or modications to this
system by other than an authorized
service facility could void
authorization to use this equipment.Tire Pressure Monitor
Operation
The Tire Pressure Monitor System
(TPMS) is designed to warn the
driver when a low tire pressure
condition exists. TPMS sensors are
mounted onto each tire and
wheel assembly, excluding the
spare tire and wheel assembly. The
TPMS sensors monitor the air
pressure in the vehicle’s tires and
transmit the tire pressure readings to
a receiver located in the vehicle.
When a low tire pressure condition is
detected, the TPMS turns on the
7
low tire pressure warning light.
At the same time a message to
check the pressure in a specic tire
appears on the Driver Information
Center (DIC) display. The low
tire pressure warning light and the
DIC warning message come on
at each ignition cycle until the tires
are inated to the correct ination
pressure. Using the DIC, tire
pressure levels can be viewed bythe driver. For additional information
and details about the DIC operation
and displays seeDIC Operation
and Displays on page 4-23andDIC
Warnings and Messages on
page 4-27.
The low tire pressure warning light
may come on in cool weather
when the vehicle is rst started, and
then turn off as you start to drive.
This could be an early indicator that
the air pressure in the tire(s) are
getting low and need to be inated
to the proper pressure.
A Tire and Loading Information label
shows the size of the vehicle’s
original equipment tires and
the correct ination pressure for the
vehicle’s tires when they are
cold. SeeLoading the Vehicle on
page 8-28, for an example of
the Tire and Loading Information
label and its location on the vehicle.
Also seeInflation - Tire Pressure
on page 9-46.
Vehicle Service and Care 9-51
2008 - Pontiac G8 Owner Manual

When It Is Time for New
Tires
Various factors, such as
maintenance, temperatures, driving
speeds, vehicle loading, and
road conditions inuence when you
need new tires.
One way to tell when it is time for
new tires is to check the treadwear
indicators, which will appear
when the tires have only 1/16 inch
(1.6 mm) or less of tread remaining.You need new tires if any of the
following statements are true:You can see the indicators at
three or more places around
the tire.
You can see cord or fabric
showing through the tire’s rubber.
The tread or sidewall is cracked,
cut, or snagged deep enough to
show cord or fabric.
The tire has a bump, bulge,
or split.
The tire has a puncture, cut, or
other damage that cannot be
repaired well because of the size
or location of the damage.
The rubber in tires degrades over
time, even if they are not being
used. This is also true for the spare
tire, if the vehicle has one. Multiple
conditions affect how fast this
aging takes place, including
temperatures, loading conditions,
and ination pressure maintenance.
With proper care and maintenance
tires typically wear out beforethey degrade due to age. If you are
unsure about the need to replace
the tires as they get older, consult
the tire manufacturer for more
information.
Buying New Tires
GM has developed and matched
specic tires for your vehicle.
The original equipment tires installed
on your vehicle, when it was new,
were designed to meet General
Motors Tire Performance Criteria
Specication (TPC Spec) system
rating. If you need replacement tires,
GM strongly recommends that
you get tires with the same TPC
Spec rating. This way, your vehicle
will continue to have tires that
are designed to give the same
performance and vehicle safety,
during normal use, as the
original tires.
9-56 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

GM’s exclusive TPC Spec system
considers over a dozen critical
specications that impact the overall
performance of your vehicle,
including brake system performance,
ride and handling, traction control,
and tire pressure monitoring
performance. GM’s TPC Spec
number is molded onto the tire’s
sidewall near the tire size. If the tires
have an all-season tread design,
the TPC Spec number will be
followed by an MS for mud and
snow. SeeTire Sidewall Labeling on
page 9-40for additional information.
GM recommends replacing tires
in sets of four. This is because
uniform tread depth on all tires will
help keep your vehicle performing
most like it did when the tires
were new. Replacing less than a full
set of tires can affect the braking
and handling performance of
your vehicle. SeeTire Inspection
and Rotation on page 9-54for
information on proper tire rotation.{CAUTION
Mixing tires could cause you
to lose control while driving.
If you mix tires of different
sizes, brands, or types
(radial and bias-belted tires),
the vehicle may not handle
properly, and you could
have a crash. Using tires of
different sizes, brands, or
types may also cause
damage to the vehicle. Be
sure to use the correct size,
brand, and type of tires on
all wheels. It is all right to
drive with the compact
spare temporarily, as it was
developed for use on the
vehicle. SeeCompact Spare
Tire on page 9-79.{CAUTION
If you use bias-ply tires on
the vehicle, the wheel rim
anges could develop
cracks after many miles of
driving. A tire and/or wheel
could fail suddenly, causing
a crash. Use only radial-ply
tires with the wheels on the
vehicle.
If you must replace your vehicle’s
tires with those that do not have
a TPC Spec number, make
sure they are the same size, load
range, speed rating, and
construction type (radial and
bias-belted tires) as your vehicle’s
original tires.
Vehicle Service and Care 9-57
2008 - Pontiac G8 Owner Manual

Vehicles that have a tire pressure
monitoring system could give
an inaccurate low-pressure warning
if non-TPC Spec rated tires are
installed on your vehicle. Non-TPC
Spec rated tires may give a
low-pressure warning that is higher
or lower than the proper warning
level you would get with TPC Spec
rated tires. SeeTire Pressure
Monitor System on page 9-49.
Your vehicle’s original equipment
tires are listed on the Tire and
Loading Information Label. See
Loading the Vehicle on page 8-28,
for more information about the
Tire and Loading Information Label
and its location on your vehicle.Different Size Tires and
Wheels
If you add wheels or tires that are a
different size than your original
equipment wheels and tires,
this may affect the way your vehicle
performs, including its braking,
ride and handling characteristics,
stability, and resistance to rollover.
Additionally, if your vehicle has
electronic systems such as, antilock
brakes, traction control, and
electronic stability control, the
performance of these systems can
be affected.
{CAUTION
If you add different sized
wheels, your vehicle may not
provide an acceptable level of
performance and safety if tires
not recommended for those
wheels are selected. You may
increase the chance that you
will crash and suffer serious
injury. Only use GM specic
wheel and tire systems
developed for your vehicle, and
have them properly installed by
a GM certied technician.
SeeBuying New Tires on page 9-56
andAccessories and Modifications
on page 9-3for additional
information.
9-58 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

Tire Chains
{CAUTION
Do not use tire chains. There is
not enough clearance. Tire
chains used on a vehicle
without the proper amount of
clearance can cause damage to
the brakes, suspension or other
vehicle parts. The area
damaged by the tire chains
could cause you to lose control
of the vehicle and you or others
may be injured in a crash.
(Continued)
CAUTION (Continued)
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size
combination and road
conditions. Follow that
manufacturer’s instructions. To
help avoid damage to the
vehicle, drive slowly, readjust
or remove the device if it is
contacting the vehicle, and do
not spin the vehicle’s wheels. If
you do nd traction devices
that will t, install them on the
front tires.
Tire Changing
If a Tire Goes Flat
It is unusual for a tire to blowout
while you are driving, especially if
you maintain your tires properly. See
Tires on page 9-39. If air goes out
of a tire, It is much more likely
to leak out slowly. But if you should
ever have a blowout, here are a
few tips about what to expect
and what to do:
If a front tire fails, the at tire will
create a drag that pulls the vehicle
toward that side. Take your foot
off the accelerator pedal and grip the
steering wheel rmly. Steer to
maintain lane position, and then
gently brake to a stop well out of the
traffic lane.
9-62 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

Storing a Flat or Spare
Tire and Tools
{CAUTION
Storing a jack, a tire, or other
equipment in the passenger
compartment of the vehicle
could cause injury. In a sudden
stop or collision, loose
equipment could strike
someone. Store all these in the
proper place.To store a at or spare tire and
tools, do the following:
A. Jack Handle
B. Nut Cap Tool
C. Wheel Wrench
D. Jack1. Replace the jack and tools as
shown.
2. Turn the retainer nut clockwise to
tighten.
3. Remove the wheel center cap by
pushing it from the back.
4. Place the at tire face up into the
spare tire hub.
5. Turn the retainer nut clockwise to
secure it into place.
6. Put the load oor back in place.
The compact spare tire is for
temporary use only. Replace the
compact spare with a full-size tire as
soon as possible.
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2008 - Pontiac G8 Owner Manual

Compact Spare Tire
Although the compact spare tire
was fully inated when the vehicle
was new, it can lose air after a time.
Check the ination pressure
regularly. It should be 60 psi
(420 kPa).
After installing the compact spare on
the vehicle, stop as soon as possible
and make sure the spare tire is
correctly inated. The compact spare
is made to perform well at speeds up
to 65 mph (105 km/h) for distances
up to 3,000 miles (5 000 km), so you
can nish your trip and have the
full-size tire repaired or replaced at
your convenience. Of course, it is
best to replace the spare with a
full-size tire as soon as possible. The
spare tire will last longer and be in
good shape in case it is needed
again.Notice:When the compact spare
is installed, do not take your
vehicle through an automatic car
wash with guide rails. The
compact spare can get caught on
the rails. That can damage the
tire and wheel, and maybe other
parts of your vehicle.
Do not use the compact spare on
other vehicles.
And do not mix the compact spare
tire or wheel with other wheels
or tires. They will not t. Keep the
spare tire and its wheel together.
Notice:Tire chains will not
t your compact spare. Using
them can damage your vehicle
and can damage the chains
too. Do not use tire chains on
your compact spare.
Vehicle Service and Care 9-79
2008 - Pontiac G8 Owner Manual