wheel size PONTIAC GRAND PRIX 2005 Owners Manual

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 A to Z.
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.
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{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
or types (radial and bias-belted tires), the
vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes may also cause damage to your vehicle.
Be sure to use the same size and type tires on
all wheels. It’s all right to drive with your
compact spare temporarily, it was developed
for use on your vehicle. SeeCompact Spare
Tire on page 5-93.
{CAUTION:
If you use bias-ply tires on your 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 your vehicle.
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, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform 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-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.
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Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can’t know how it’s been used
or how far it’s been driven. It could fail suddenly
and cause a crash. If you have to replace a
wheel, use a new GM original equipment wheel.
Tire Chains
{CAUTION:
If your vehicle has P225/55R17 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 manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your wheels.
If you do nd traction devices that will t, install
them on the front tires.
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Notice:If your vehicle does not have P225/55R17
size tires, use tire chains only where legal and
only when you must. Use only SAE Class “S” type
chains that are the proper size for your tires.
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
instructions. If you can hear the chains contacting
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 “blowout” 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 “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.A rear blowout, 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
accelerator 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.
{CAUTION:
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 at 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 changing a at tire.
If a tire goes at, the next part shows how to use your
jacking equipment to change a at tire safely.
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8. Tighten the wheel nuts
rmly in a crisscross
sequence as shown.
9. Reinstall the wheel trim. If the vehicle has plastic
caps, tighten them by hand. With the wheel
wrench, tighten the plastic caps an additional
quarter turn clockwise.
Notice:Wheel covers will not t on your compact
spare. If you try to put a wheel cover on the compact
spare, you could damage the cover or the spare.
10. Do not try to put the wheel cover on the compact
spare tire. It will not t. Store the wheel cover in
the trunk until the at tire is repaired or replaced.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.
After the compact spare tire is put on the vehicle, store
the at tire in the trunk. Use the following procedure
to secure it in the trunk.
When storing a full-size tire, use the extension and
protector/guide, located in the foam holder to help avoid
wheel surface damage.
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To store a full-size tire, do the following:
1. Place the tire in the trunk with the valve stem facing
down, and the protector/guide placed through a
wheel bolt hole.
2. Remove the protector and attach the retainer
securely.
3. Place the protector/guide back in the foam holder
when putting the compact spare back in the trunk.
Store the cover as far forward as possible.
The compact spare tire is for temporary use only.
Replace the compact spare tire with a full-size tire as
soon as possible. SeeCompact Spare Tire on
page 5-93. See the storage instructions label on the
trunk lid to properly position the compact spare tire
in the trunk.A. Retainer
B. Cover
C. Compact Spare Tire
D. Nut
E. Jack
F. Wheel Wrench
G. Extension and
Protective Guide
H. Foam Holder
I. Bolt Screw
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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.
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