2004 Mercury Grand Marquis tire size

•Extra load:A class of P-metric or Metric tires designed to carry a
heavier maximum load at 41 psi [43 psi (2.9 bar) for Metric tires].
Increasing the inflation pressure beyond this pressure will not increase
the tires load carrying capability.
•kPa:Kilopascal, a metric unit of air pressure.
•PSI:Pounds per square inch, a standard unit of air pressure.
•B-pillar:The structural member at the side of the vehicle behind the
front door.
•Bead area of the tire:Area of the tire next to the rim.
•Sidewall of the tire:Area between the bead area and the tread.
•Tread area of the tire:Area of the perimeter of the tire that
contacts the road when mounted on the vehicle.
•Rim:The metal support (wheel) for a tire or a tire and tube assembly
upon which the tire beads are seated.
INFORMATION CONTAINED ON THE TIRE SIDEWALL
Federal law requires tire manufacturers to place standardized
information on the sidewall of all tires. This information identifies and
describes the fundamental characteristics of the tire and also provides a
U.S. DOT Tire Identification Number for safety standard certification and
in case of a recall.
Information on“P”type tires
P215/65R15 95H is an example of a
tire size, load index and speed
rating. The definitions of these
items are listed below. (Note that
the tire size, load index and speed
rating for your vehicle may be
different than this example.)
1.P:Indicates a tire, designated by
the Tire and Rim Association
(T&RA), that may be used for
service on cars, SUVs, minivans and
light trucks.
Note:If your tire size does not
begin with a letter this may mean it
is designated by either ETRTO
(European Tire and Rim Technical Organization) or JATMA (Japan Tire
Manufacturing Association).
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
213

2.215:Indicates the nominal width of the tire in millimeters from
sidewall edge to sidewall edge. In general, the larger the number, the
wider the tire.
3.65:Indicates the aspect ratio which gives the tire’s ratio of height to
width.
4.R:Indicates a“radial”type tire.
5.15:Indicates the wheel or rim diameter in inches. If you change your
wheel size, you will have to purchase new tires to match the new wheel
diameter.
6.95:Indicates the tire’s load index. It is an index that relates to how
much weight a tire can carry. You may find this information in your
owner’s guide. If not, contact a local tire dealer.
Note:You may not find this information on all tires because it is not
required by federal law.
7.H:Indicates the tire’s speed rating. The speed rating denotes the
speed at which a tire is designed to be driven for extended periods of
time under a standard condition of load and inflation pressure. The tires
on your vehicle may operate at different conditions for load and inflation
pressure. These speed ratings may need to be adjusted for the difference
in conditions. The ratings range from 99 mph (159 km/h) to 186 mph
(299 km/h). These ratings are listed in the following chart.
Note:You may not find this information on all tires because it is not
required by federal law.
Letter rating Speed rating - mph (km/h)
Q 99 mph (159 km/h)
R 106 mph (171 km/h)
S 112 mph (180 km/h)
T 118 mph (190 km/h)
U 124 mph (200 km/h)
H 130 mph (210 km/h)
V 149 mph (240 km/h)
W 168 mph (270 km/h)
Y 186 mph (299 km/h)
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
214

Letter rating Speed rating - mph (km/h)
Note:For tires with a maximum speed capability over 149 mph
(240 km/h), tire manufacturers sometimes use the letters ZR. For
those with a maximum speed capability over 186 mph (299 km/h), tire
manufacturers always use the letters ZR.
8.U.S. DOT Tire Identification Number (TIN):This begins with the
letters“DOT”and indicates that the tire meets all federal standards. The
next two numbers or letters are the plant code where it was
manufactured, the next two are the tire size code and the last four
numbers represent the week and year the tire was built. For example,
the numbers 317 mean the 31st week of 1997. After 2000 the numbers
go to four digits. For example, 2501 means the 25th week of 2001. The
numbers in between are identification codes used for traceability. This
information is used to contact customers if a tire defect requires a recall.
9.M+S or M/S:Mud and Snow. or
AT:All Terrain. or
AS:All Season.
10.Tire Ply Composition and Material Used:Indicates the number of
plies or the number of layers of rubber-coated fabric in the tire tread and
sidewall. Tire manufacturers also must indicate the ply materials in the
tire and the sidewall, which include steel, nylon, polyester, and others.
11.Maximum Load:Indicates the maximum load in kilograms and
pounds that can be carried by the tire. Refer to the tire label or the
safety certification label, located on the B-Pillar or the driver’s door, for
the correct tire pressure for your vehicle
12.Treadwear, Traction and Temperature Grades
•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 one-half (1
1⁄2) times as well on the government
course as a tire graded 100.
•Traction:The traction grades, from highest to lowest are AA, A, B,
and C. The grades represent the tire’s ability to stop on wet pavement
as measured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor
traction performance.
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
215

Information on“T”type tires
T145/80D16 is an example of a tire
size.
Note:The temporary tire size for
your vehicle may be different than
this example.
1.T:Indicates a type of tire,
designated by the Tire and Rim
Association (T&RA), that is
intended for temporary service on
cars, SUVs, minivans and light
trucks.
2.145:Indicates the nominal width
of the tire in millimeters from
sidewall edge to sidewall edge. In
general, the larger the number, the
wider the tire.
3.80:Indicates the aspect ratio
which gives the tires ratio of height to width. Numbers of 70 or lower
indicate a short sidewall.
4.D:Indicates a“diagonal”type tire.
R:Indicates a“radial”type tire.
5.16:Indicates the wheel or rim diameter in inches. If you change your
wheel size, you will have to purchase new tires to match the new wheel
diameter.
Location of the tire label
You will find a tire label containing tire inflation pressure by tire size and
other important information located on the B-Pillar or the driver’s door.
TIRE CARE
Improper or inadequate vehicle maintenance can also cause tires to wear
abnormally. Here are some of the important maintenance items:
Tire inflation pressure
Use a tire gauge to check the tire inflation pressure, including the spare,
at least monthly and before long trips. You are strongly urged to buy a
reliable tire pressure gauge, as automatic service station gauges may be
inaccurate. Ford recommends the use of a digital or dial type tire
pressure gauge rather than a stick type tire pressure gauge.
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
217

Sometimes irregular tire wear can be corrected by rotating the tires.
Note:If your tires show uneven wear ask a qualified technician at a
Ford or Lincoln/Mercury dealership to check for and correct any wheel
misalignment, tire imbalance or mechanical problem involved before tire
rotation.
Note:Your vehicle may be equipped with a dissimilar spare tire/wheel. A
dissimilar spare tire/wheel is defined as a spare tire and/or wheel that is
different in brand, size or appearance from the road tires and wheels. If
you have a dissimilar spare tire/wheel it is intended for temporary use
only and should not be used in a tire rotation.
Note:After having your tires rotated, inflation pressure must be checked
and adjusted to the vehicle requirements.
Tire wear
Measure and inspect the tire tread on all your tires periodically.
Advanced and unusual tire wear can reduce the ability of tread to grip
the road in adverse (wet, snowy, etc.) conditions. Visually check your
tires for uneven wear, looking for high and low areas or unusually
smooth areas. Also check for signs of tire damage.
When the tread is worn down to
1/16th of an inch (2 mm), tires must
be replaced to prevent your vehicle
from skidding and hydroplaning.
Built-in treadwear indicators, or
“wear bars”, which look like narrow
strips of smooth rubber across the
tread will appear on the tire when
the tread is worn down to 1/16th of an inch (2 mm). When you see these
“wear bars”, the tire is worn out and should be replaced.
Inspect your tires frequently for any of the following conditions and
replace them if one or more of the following conditions exist:
•Fabric showing through the tire rubber
•Bulges in the tread or sidewalls
•Cracks or cuts on the sidewalls
•Cracks in the tread groove
•Impact damage resulting from use
•Separation in the tread
•Separation in the sidewall
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
221

•Severe abrasion on the sidewall
If your vehicle has a leak in the exhaust system, a road tire or the spare
tire may be exposed to hot exhaust temperatures requiring the tire to be
replaced.
Tire Replacement Requirements
Your vehicle is equipped with tires designed to provide safe ride and
handling capability.
Only use replacement tires and wheels that are the same size
and type (such as P-metric versus LT-metric or all-season versus
all-terrain) as those originally provided by Ford. Use of any tire or
wheel not recommended by Ford can affect the safety and
performance of your vehicle, which could result in an increased risk of
loss of vehicle control, vehicle rollover, personal injury and death.
Additionally the use of non-recommended tires and wheels could cause
steering, suspension, axle or transfer case/power transfer unit failure. If
you have questions regarding tire replacement, see an authorized Ford
or Lincoln/Mercury dealer.
Make sure all tires and wheels on the vehicle are of the same size, type,
tread design, brand, load-carrying capacity and speed rating because it
can affect the safety and performance of your vehicle, which could result
in an increased risk of loss of vehicle control, vehicle rollover, personal
injury and death.
You should replace the spare tire when you replace the other road tires
due to the aging of the spare tire.
Safety practices
Driving habits have a great deal to do with your tire mileage and safety.
•Observe posted speed limits
•Avoid fast starts, stops and turns
•Avoid potholes and objects on the road
•Do not run over curbs or hit the tire against a curb when parking
If your vehicle is stuck in snow, mud, sand, etc.,do notrapidly spin the
tires; spinning the tires can tear the tire and cause an explosion. A tire
can explode in as little as three to five seconds.
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
222

Tire explosions can cause death, personal injury or property
damage. Do not allow anyone to stand near, directly ahead or
behind the spinning tire.
Never spin the tires in excess of the 35 mph (55 km/h) point
indicated on the speedometer.
Highway hazards
No matter how carefully you drive there’s always the possibility that you
may eventually have a flat tire on the highway. Drive slowly to the
closest safe area out of traffic. This may further damage the flat tire, but
your safety is more important.
If you feel a sudden vibration or ride disturbance while driving, or you
suspect your tire or vehicle has been damaged, immediately reduce your
speed. Drive with caution until you can safely pull off the road. Stop and
inspect the tires for damage. If a tire is under-inflated or damaged,
deflate it, remove wheel and replace it with your spare tire and wheel. If
you cannot detect a cause, have the vehicle towed to the nearest repair
facility or tire dealer to have the vehicle inspected.
SNOW TIRES AND CHAINS
Snow tires must be the same size and grade as the tires you
currently have on your vehicle.
The tires on your vehicle have all weather treads to provide traction in
rain and snow. However, in some climates, you may need to use snow
tires and chains.
Follow these guidelines when using snow tires and chains:
•Either cable type chains or SAE class S chains can be used.
•Install chains securely, verifying that the chains do not touch any
wiring, brake lines or fuel lines.
•Drive cautiously. If you hear the chains rub or bang against your
vehicle, stop and re-tighten the chains. If this does not work, remove
the chains to prevent damage to your vehicle.
•If possible, avoid fully loading your vehicle.
•Remove the tire chains when they are no longer needed. Do not use
tire chains on dry roads.
2004 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA English(fus)
Maintenance and Specifications
223