2008 PONTIAC G8 width

{CAUTION
You can be seriously injured by
not wearing the lap-shoulder
belt properly. In a crash, you
would not be restrained by the
shoulder belt. Your body could
move too far forward increasing
the chance of head and neck
injury. You might also slide
under the lap belt. The belt
force would then be applied
right on the abdomen. That
could cause serious or fatal
injuries. The shoulder belt
should go over the shoulder
and across the chest.
Q:What is wrong with this?
A:The belt is twisted across
the body.
{CAUTION
You can be seriously injured by
a twisted belt. In a crash, you
would not have the full width
of the belt to spread impact
forces. If a belt is twisted,
make it straight so it can
work properly, or ask your
dealer/retailer to x it.
Seats and Restraints 1-13
2008 - Pontiac G8 Owner Manual

4. At the wall, measure from the
ground upward (A) to the
recorded distance from Step 3
and mark it.
5. Draw or tape a horizontal line (B)
on the wall the width of the
vehicle at the height of the mark
in Step 4.
Notice:Do not cover a headlamp
to improve beam cut-off when
aiming. Covering a headlamp may
cause excessive heat build-up
which may cause damage to the
headlamp.6. Turn on the low-beam headlamps
and place a piece of cardboard
or equivalent in front of the
headlamp not being adjusted.
Do not place it directly on
the headlamp. This allows only
the beam of light from the
headlamp being adjusted to be
seen on the at surface.
7. Locate the vertical headlamp
aiming screws, which are
under the hood near each
headlamp assembly.The adjustment screw can be
turned with a 6 mm socket
wrench.
8. Turn the vertical aiming screw
clockwise or counterclockwise
until the headlamp beam is
aimed to the horizontal tape line.
9. Make sure that the light from the
headlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the left (A)
shows the correct headlamp aim.
The lamp on the right (B) shows
the incorrect headlamp aim.
10. Repeat Steps 7 through 9 for
the opposite headlamp.
Driver Side (Passenger
Side Similar)
9-28 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The
examples show a typical
passenger vehicle tire and a
compact spare tire sidewall.(A) Tire Size
:The tire size is a
combination of letters and
numbers used to dene a
particular tire’s width, height,
aspect ratio, construction
type, and service description.
See the “Tire Size” illustration
later in this section for more
detail.
(B) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications
meet or exceed all federal safety
guidelines.(C) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that
the tire is in compliance with
the U.S. Department of
Transportation Motor Vehicle
Safety Standards.
(D) Tire Identication Number
(TIN)
:The letters and numbers
following DOT (Department
of Transportation) code is the
Tire Identication Number (TIN).
The TIN shows the manufacturer
and plant code, tire size, and
date the tire was manufactured.
The TIN is molded onto both
sides of the tire, although
only one side may have the date
of manufacture.
Passenger (P-Metric) Tire
Example
9-40 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

(E) Tire Ination:The
temporary use tire or compact
spare tire should be inated
to 60 psi (420 kPa). For
more information on tire
pressure and ination see
Inflation - Tire Pressure on
page 9-46.
(F) Tire Size
:A combination of
letters and numbers dene a
tire’s width, height, aspect ratio,
construction type, and service
description. The letter T as
the rst character in the tire size
means the tire is for temporary
use only.
(G) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications
meet or exceed all federal safety
guidelines.Tire Size
The following illustration shows
an example of a typical
passenger vehicle tire size.
(A) Passenger (P-Metric) Tire
:The United States version of a
metric tire sizing system. The
letter P as the rst character in
the tire size means a passenger
vehicle tire engineered to
standards set by the U.S. Tire
and Rim Association.
(B) Tire Width
:The three-digit
number indicates the tire
section width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two-digit
number that indicates the tire
height-to-width measurements.For example, if the tire size
aspect ratio is 60, as shown in
item C of the illustration, it would
mean that the tire’s sidewall is
60 percent as high as it is wide.
(D) Construction Code
:A letter
code is used to indicate the type
of ply construction in the tire. The
letter R means radial ply
construction; the letter D means
diagonal or bias ply construction;
and the letter B means
belted-bias ply construction.
(E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Service Description
:These
characters represent the load
range and speed rating of the
tire. The load index represents
the load carry capacity a tire is
certied to carry. The load index
can range from 1 to 279. The
speed rating is the maximum
speed a tire is certied to carry a
load. Speed ratings range from
AtoZ.
9-42 Vehicle Service and Care
2008 - Pontiac G8 Owner Manual

Tire Terminology and
Denitions
Air Pressure:The amount of
air inside the tire pressing
outward on each square inch of
the tire. Air pressure is
expressed in pounds per square
inch (psi) or kilopascal (kPa).
Accessory Weight
:This means
the combined weight of optional
accessories. Some examples of
optional accessories are,
automatic transmission, power
steering, power brakes, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire’s height to its width.
Belt
:A rubber coated layer of
cords that is located between the
plies and the tread. Cords
may be made from steel or other
reinforcing materials.Bead
:The tire bead contains
steel wires wrapped by steel
cords that hold the tire onto
the rim.
Bias Ply Tire
:A pneumatic tire
in which the plies are laid at
alternate angles less than
90 degrees to the centerline of
the tread.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in pounds per square
inch (psi) or kilopascals (kPa)
before a tire has built up heat
from driving. SeeInflation - Tire
Pressure on page 9-46.
Curb Weight
:The weight of a
motor vehicle with standard
and optional equipment including
the maximum capacity of fuel,
oil, and coolant, but without
passengers and cargo.DOT Markings
:A code
molded into the sidewall of a
tire signifying that the tire
is in compliance with the
U.S. Department of
Transportation (DOT) motor
vehicle safety standards.
The DOT code includes the Tire
Identication Number (TIN),
an alphanumeric designator
which can also identify the tire
manufacturer, production
plant, brand, and date of
production.
GVWR
:Gross Vehicle Weight
Rating. SeeLoading the Vehicle
on page 8-28.
GAWR FRT
:Gross Axle Weight
Rating for the front axle. See
Loading the Vehicle on
page 8-28.
Vehicle Service and Care 9-43
2008 - Pontiac G8 Owner Manual

Uniform Tire Quality
Grading
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
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires by
treadwear, traction, and
temperature performance. This
applies only to vehicles sold in
the United States. The gradesare molded on the sidewalls of
most passenger car tires. The
Uniform Tire Quality Grading
(UTQG) system does not apply to
deep tread, winter-type snow
tires, space-saver, or temporary
use spare tires, tires with nominal
rim diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
General Motors passenger cars
and light trucks may vary
with respect to these grades,
they must also conform to
federal safety requirements and
additional General Motors
Tire Performance Criteria (TPC)
standards.Treadwear
The treadwear grade is a
comparative rating based on the
wear rate of the tire when
tested under controlled
conditions on a specied
government test course. For
example, a tire graded
150 would wear one and a half
(1.5) 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, however, and may
depart signicantly from the
norm due to variations in driving
habits, service practices, and
differences in road
characteristics and climate.
Vehicle Service and Care 9-59
2008 - Pontiac G8 Owner Manual

the alignment might need to be
checked. If you notice your vehicle
vibrating when driving on a
smooth road, the tires and wheels
might need to be rebalanced.
See your dealer/retailer for proper
diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked or badly rusted or corroded.
If wheel nuts keep coming loose,
the wheel, wheel bolts and
wheel nuts should be replaced. If
the wheel leaks air, replace it
(except some aluminum wheels,
which can sometimes be repaired).
See your dealer/retailer if any of
these conditions exist.
Your dealer/retailer will know the
kind of wheel you need.
Each new wheel should have the
same load-carrying capacity,
diameter, width, offset and be
mounted the same way as the one
it replaces.If you need to replace any of the
wheels, wheel bolts or wheel
nuts, replace them only with new
GM original equipment parts.
This way, you will be sure to have
the right wheel, wheel bolts and
wheel nuts for the vehicle.
{CAUTION
Using the wrong replacement
wheels, wheel bolts, or wheel
nuts on your vehicle can be
dangerous. It could affect the
braking and handling of your
vehicle, make your tires lose air
and make you lose control. You
could have a collision in which
you or others could be injured.
Always use the correct wheel,
wheel bolts, and wheel nuts for
replacement.Notice:The wrong wheel can
also cause problems with bearing
life, brake cooling, speedometer
or odometer calibration,
headlamp aim, bumper height,
vehicle ground clearance, and tire
or tire chain clearance to the
body and chassis.
SeeChanging a Flat Tire (V6
Engine) on page 9-71for more
information.
Used Replacement Wheels
{CAUTION
Putting a used wheel on the
vehicle is dangerous. You
cannot know how it has been
used or how far it has been
driven. It could fail suddenly
and cause a crash. If you have
to replace a wheel, use a new
GM original equipment wheel.
Vehicle Service and Care 9-61
2008 - Pontiac G8 Owner Manual