
226 Car care and technical informationUniform Tire Quality GradingQuality grades can be found where applica-
ble on the tire sidewall between tread shoul-
der and maximum section width. For exam-
ple:
Treadwear 200 Traction AA
Temperature A
The following information relates to the
system developed by the United States
National Highway Traffic Safety Administra-
tion, which grades tires by treadwear, trac-
tion and temperature performance. (This
applies only to vehicles sold in the United
States.) The grades are molded on the side-
walls of most passenger car tires. The Uni-
form Tire Quality Grading 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-pro-
duction 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 Perfor-
mance 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 specified government test course. For
example, a tire graded 150 would wear one
and a half (1.5) times as well on the govern-
ment course as a tire graded 100. The rela-
tive performance of tires depends upon the
actual conditions of their use, however, and
may depart significantly from the norm due
to variations in driving habits, service prac-
tices and differences in road characteristics
and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest,
are AA, A, B, and C. Those grades repre-
sent the tire’s ability to stop on wet pave-
ment as measured under controlled condi-
tions on specified government test surfaces
of asphalt and concrete. A tire marked C
may have poor traction performance. Warn-
ing: The traction grade assigned to this tire
is based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.Temperature – A, B, C
The temperature grades are A (the highest),
B, and C, representing the tire’s resistance
to the generation of heat and its ability to dis-
sipate heat when tested under controlled
conditions on a specified indoor laboratory
test wheel. Sustained high temperature can
cause the material of the tire to degenerate
and reduce tire life, and excessive temper-
ature can lead to sudden tire failure. The
grade C corresponds to a level of perfor-
mance which all passenger car tires must
meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A
represent higher levels of performance on
the laboratory test wheel than the minimum
required by law.
Warning: The temperature grade for this tire
is established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, or excessive loading,
either separately or in combination, can
cause heat buildup and possible tire failure.95_U S _M 07.book Page 226 Friday, June 9, 2006 8:58 AM
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228 Car care and technical informationTire Chains
Notice:
If your vehicle does not have
225/45R17 alt. 235/45 R17 size tires, use
tire chains only where legal and only
when you must. Contact your Saab
dealer regarding suitable snow chains.
Install them on the front tires and tighten
them as tightly as possible with the ends
securely fastened. Drive slowly and
follow the chain manufacturer’s instruc-
tions. If you can hear the chains contact-
ing your vehicle, stop and retighten
them. If the contact continues, slow
down until it stops. Driving too fast or
spinning the wheels with chains on will
damage your vehicle.If a Tire Goes Flat
It’s unusual for a tire to “blow-out” while
you’re driving, especially if you maintain
your tires properly. If air goes out of a tire,
it’s much more likely to leak out slowly. But
if you should ever have a “blow-out”, here
are a few tips about what to expect and what
to do:
If a front tire fails, the flat tire will create a
drag that pulls the vehicle toward that side.
Take your foot off the accelerator pedal and
grip the steering wheel firmly. Steer to main-
tain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blow-out, particularly on a curve, acts
much like a skid and may require the same
correction you’d use in a skid. In any rear
blowout, remove your foot from the acceler-
ator pedal. Get the vehicle under control by
steering the way you want the vehicle to go.
It may be very bumpy and noisy, but you can
still steer. Gently brake to a stop – well off
the road if possible.
If a tire goes flat, the next part shows how to
use your jacking equipment to change a flat
tire safely.
WARNING
If your vehicle has 225/45 R17 alt. 235/45
R17 size tires, don’t use tire chains,
there’s 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 your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if
its manufacturer recommends it for use
on your vehicle and tire size combination
and road conditions. Follow that manu-
facturer’s instructions. To help avoid
damage to your vehicle, drive slowly,
readjust or remove the device if it’s con-
tacting your vehicle, and don’t spin your
wheels.
If you do find traction devices that will fit,
install them on the front tires.95_U S _M 07.book Page 228 Friday, June 9, 2006 8:58 AM
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229 Car care and technical information
Tire Sidewall LabelingUseful information about a tire is molded
into it´s sidewall.
Tire size: The tire size ia a combination of
letters and numbers used to define a partic-
ular tire´s width, height, aspect ratio, con-
struction type and service description.
Department of Transportation (DOT):
The Department of Transportation (DOT)
code indicates that the tire is in compliance
with the U.S. Department of Transportation
Motor Vehicle Safety standards.
Tire Identification Number (TIN): The let-
ters and numbers following DOT code are
the Tire Identification Number (TIN). The
TIN shows the manufacturer and plant
code, tire size, and date the tire was manu-
factured. The TIN is molded onto both sides
of the tire.
Tire Ply Material: The type of cord and
number of plies in the sidewall and under
the tread.Uniform Tire Quality Grading (UTQG):
Tire manufacturers are required to grade
tires based on performance factors: tread-
wear, traction and temperature resistance.
For more information see “Uniform Tire
Quality Grading” on page 226.
Maximum Cold Inflation Load Limit: Max-
imum load that can be carried and the max-
imum pressure needed to support that load.
For information on recommended tire pres-
sure see “Lowest recommended tire pres-
sure, cold tires” on page 267and “Loading
Your Vehicle” on page 231.
Tire SizeThe following illustration shows an example
of a typical passenger car tire size.
Tire Width: The three-digit number indi-
cates the tire section width in millimeters
from sidewall to sidewall.215/55 R 16 93 H
| |||||
abcdef
aTire Width
b Aspect Ratio
c Belt Rating
d Rim diameter
e Load range
f Speed rating
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231 Car care and technical information
Loading Your VehicleThis is an example of what your vehicle´s
Tire-Loading Information/Certification label
might look like. It is located on the B-pillar
and shows how much weight your vehicle
may properly carry. The label tells you the
proper size, and recommended inflation
pressures for the tires on your vehicle. It
also gives you important information about
the number of people that can be in your
vehicle and the total weight that you can
carry. This weight is called the Vehicle
Capacity Weight, and includes the weight of
all occupants, cargo and all nonfac-
tory-installed options.
Tire Terminology and DefinitionsAir 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 com-
bined weight of optional accessories, for
example, automatic transmission, power
steering, power brakes, power windows,
power seats, radio 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 rein-
forcing materials.
Bias Ply Tire: A pneumatic tire in which the
ply cords that extend to the beads are laid at
alternate angles substantially less than 90
degrees to the centerline of the tread.
Cold Inflation Pressure: The amount of air
pressure in a tire, measured in pounds per
square inch (psi) or kilopascal (kPa), before
a tire have built up heat from driving. See
“Inflation - Tire Pressure” on page 222.
Curb weight: This means the weight of a
motor vehicle with standard and optional
equipment including the maximum capacity
of fuel, oil and coolant, 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 motor vehicle safety stan-
dards. The DOT code includes the Tire
Identification Number (TIN), an alphanu-
meric designator which can also identify the
tire manufacturer, production plant, brand
and date of production.
GVWR: Gross Vehicle Weight Rating see
“Loading Your Vehicle” on page 231.
GAWR FRT: Gross Axle Weight Rating for
the front axle, see “Loading Your Vehicle”
on page 231.
GAWR RR: Gross Axle Weight Rating for
the rear axle, see “Loading Your Vehicle” on
page 231.
Intended Outboard Sidewall: The side of
an asymmetrical tire that must always face
outward when mounted on a vehicle.
Kilopascal (kPa): The metric unit for air
pressure. There are 6.9 kPa to one psi.
Light Truck (LT-Metric) Tire: A tire used
on light duty trucks and some multipurpose
passenger vehicles.
Load Index: An assigned number ranging
from 1 to 279 that corresponds to the load
carrying capacity of a tire.
This label can only be found on vehicles
sold in the U.S.
Vehicles sold in Canada have the tire
information label in the glovebox, see
page 268.
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232 Car care and technical informationMaximum Load rating: The load rating for
a tire at the maximum permissible inflation
pressure for that tire.
Maximum Loaded Vehicle Weight: The
sum of curb weight; accessory weight; vehi-
cle capacity weight; and production options
weight.
Maximum Permissible Inflation Pres-
sure: The maximum cold inflation pressure
to which a tire may be inflated.
Normal occupant weight: The number of
occupants a vehicle is designed to seat mul-
tipled by 150 pounds (68 kg). See “Loading
Your Vehicle” on page 231.
Occupant Distribution: Designated seat-
ing positions.
Outward Facing Sidewall: The side of a
asymmetrical tire that has a particular side
that faces outward when mounted on a vehi-
cle. The side of the tire that contains a white-
wall bears white lettering or bears manufac-
turer, brand and or model name molding on
the other sidewall of the tire.
Passenger (P-Metric) Tire: A tire used on
passenger cars and some light duty trucks
and multipurpose vehicles.Recommended Inflation Pressure: Vehi-
cle manufacturer´s recommended tire infla-
tion pressure shown on the tire label, see
“Inflation - Tire Pressure” on page 222 and
“Loading Your Vehicle” on page 231.
Radial Ply Tire: A pneumatic tire in which
the ply cords that extend to the beads are
laid at substantially 90 degrees to the cen-
terline of the tread.
Rim: A metal support for a tire or a tire and
tube assembly upon which the tire beads
are seated.
Sidewall: The portion of a tire between the
tread and the bead.
Speed rating: An alphanumeric code
assigned to a tire indicating the maximum
speed at which a tire can operate.
Traction: The friction between the tire and
the road surface. The amount of grip pro-
vided.
Treadwear Indicators: Narrow bands,
sometimes called “wear bars”, that show
across the tread of a tire when only
2/32 inch of tread remains. See “When It Is
Time for New Tires” on page 224.Tread Width: The width of the tire´s tread.
UTQGS: Uniform Tire Quality Grade Stan-
dards, a tire information system that pro-
vides consumers with ratings for a tire´s
traction, temperature and treadwear. Rat-
ings are determined by tire manufacturers
using government testing procedures. The
rating are molded into the sidewall of the
tire. See “Uniform Tire Quality Grading” on
page 226.
Vehicle Capacity Weight: Is the number of
designated seating positions multipled by
150 pounds (68 kg) plus the rated cargo
load. See “Loading Your Vehicle” on
page 231.
Vehicle Maximum Load on the Tire: Load
on an individual tire due to curb weight,
accessory weight, occupant weight and
cargo weight.
Vehicle label: A label permanently
attached to a vehicle showing original
equipment tire size and the recommended
cold inflation pressure. See “Loading Your
Vehicle” on page 231.95_U S _M 07.book Page 232 Friday, June 9, 2006 8:58 AM
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234 Car care and technical informationTire date codeTires should be regarded as perishable
goods. As the tires age, the rubber becomes
progressively harder, and the roadholding
ability of the tires diminishes. This is partic-
ularly true on winter tires.
Tires now have a date-code marking for the
year of manufacture. The first two digits
denote the week number and the two last
digits the year followed by a filled triangle.
Compact spare tireThe compact spare is light and easy to
handle when changing the tire. Its use is
only permitted when a standard tire has sus-
tained a puncture. The maximum life of the
tire is only 2000 miles (3,500 km).
Do not exceed 50 mph (80 km/h) with the
compact spare fitted.
The compact spare should be inflated to
60 psi (420 kPa). Carry the punctured tire in the spare-wheel well under the luggage-
compartment floor.
Have the standard tire repaired and refitted
as soon as possible.
The spare tire, together with the jack, front
towrope attachment eye and toolkit, is
stowed away underneath the luggage-com-
partment floor.
WARNING
Stow all tools carefully away after use, so
that they cannot get loose and cause
injury in the event of a crash.
NOTICETo avoid damaging a punctured alloy
wheel it can be placed outside up in the
spare-wheel well but only while driving to
the closest dealer.
A general rule is that all heavy loads must
be well secured in the luggage compart-
ment, see page 131 and 135.
IB3233
Spare wheel (under panel in luggage
compartment)
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236 Car care and technical informationChanging a wheel
WARNING
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous
without the appropriate safety equipment
and training. The jack provided with your
vehicle is designed only for changing a
flat tire. If it is used for anything else, you
or others could be badly injured or killed if
the vehicle slips off the jack. Use the jack
provided with your vehicle only for chang-
ing a flat tire.
Changing a tire can be dangerous. The
vehicle can slip off the jack and roll over
or fall on you or other people. You and
they could be badly injured or even killed.
Find a level place to change your tire. To
help prevent the vehicle from moving:
1 Set the parking brake firmly.
2 If you have an automatic transmis-
sion, put the shift lever in PARK (P).
For a manual transmission, leave the
car in gear (1st or REVERSE (R)).
3 Turn off the engine and do not restart
while the vehicle is raised.
4 Do not allow passengers to remain in
the vehicle.
To be even more certain the vehicle won't
move, you should put blocks at the front
and rear of the tire farthest away from the
one being changed. That would be the
tire, on the other side, at the opposite end
of the vehicle.
The car jack is designed solely for use
in changing a wheel or fitting snow
chains. It must not be used to sup-
port the car during repair work or
servicing.
Never crawl under a car that is
supported only by a jack.
Raising your vehicle too high or with
the jack improperly positioned can
damage the vehicle and even make
the vehicle fall. To help avoid personal
injury and vehicle damage, be sure to
fit the jack lift head into the proper
location before raising the vehicle, and
raise the vehicle only far enough off
the ground so there is enough room
for the spare tire to fit (no more than
25 mm or 1 inch clearance between
the ground and the bottom of the tire).
Switch on the hazard warning lights if
the car is on a road.
The jack should be stored correctly
under the carpeting in the trunk. If it
lies loose in the car, it could thrown for-
ward and cause personal injury in the
event of a crash or if the car rolls over.
Grit, salt and rust can clog the inner
threads of the wheel bolts if the car has
been driven for several years exclu-
sively with alloy wheels.
If steel wheels are being installed, the
bolt hole threads in the brake hubs
should be cleaned before the thinner
steel wheels are fitted. It may other-
wise not be possible to achieve the
correct clamping force, despite tight-
ening the wheel bolts to the correct
torque.
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248 Car care and technical information The vehicle should be fully assembled
and all other work stopped while headlight
aiming is being done.
The vehicle should not have any snow,
ice or mud attached to it.
Tires should be inflated to the prescribed
pressure.
Close all doors.
Rock the vehicle to stabilize the suspen-
sion.
Headlight aiming is done with the vehicle
low beam lamps. The high beam lamps will
be correctly aimed if the low beam lamps
are aimed properly.
If you find that the headlight needs adjust-
ment follow these steps:
1 Open the hood and locate the vertical
aiming device.
2 Locate the marker on the lens.
3 Measure the distance from the ground to
the aim marker on each lens.
Subtract 2 inches if the vehicle is
equipped with halogen lamps, record
this distance.
Subtract 3 inches if the vehicle is
equipped with xenon lamps, record this
distance.4 At the wall or other flat surface, measure
from the ground to the recorded dis-
tance (see point 4) and draw a horizontal
line the width of the vehicle.
IB1950
2
14
3
1 Wall or garage door
2 25 ft (7.6 m) between wall and headlight lens.
3 Measurement from the ground to the low beam aiming marker on the headlight lens.
4 Same measurement as (3) but substract 2 inches for vehicles with halogen lamps and
3 inches for vehicles with xenon lamps.
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