Ford F-150 Heritage (2004 year). Manual — part 54

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 for 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, which is located on the B-Pillar or the edge of
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.

• Temperature: The temperature grades are A (the highest), B and C,

representing the tire’s resistance to the generation of heat and its
ability to dissipate heat when tested under controlled conditions on a
specified indoor laboratory test wheel.

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13. Maximum Permissible Inflation Pressure: Tire manufacturer’s
maximum permissible pressure and/or the pressure at which the
maximum load can be carried by the tire. This pressure is normally
higher than the manufacturer’s recommended cold inflation pressure
which can be found on either the tire label or certification label which is
located B-Pillar or the edge of the driver’s door. The cold inflation
pressure should never be set lower than the recommended pressure on
the vehicle label.

The tire suppliers may have additional markings, notes or warnings such
as standard load, radial tubeless, etc.

Additional information contained on the tire sidewall for “LT” type
tires

“LT” type tires have some additional
information beyond those of “P”
type tires; these differences are
described below:

1. LT: Indicates a tire, designated by
the Tire and Rim Association
(T&RA), that is intended for service
on light trucks.

2. Load Range/Load Inflation
Limits: Indicates the tire’s
load-carrying capabilities and its
inflation limits.

3. Maximum Load Dual lbs. (kg)
at psi (kPa) cold: Indicates the
maximum load and tire pressure
when the tire is used as a dual;
defined as four tires on the rear axle (a total of six or more tires on the
vehicle).

4. Maximum Load Single lbs. (kg) at psi (kPa) cold: Indicates the
maximum load and tire pressure when the tire is used as a single;
defined as two tires (total) on the rear axle.

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219

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 from
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 tire’s 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 edge of the
driver’s door.

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220

TIRE CARE

Improper or inadequate vehicle maintenance can also cause tires to wear
abnormally. Here are some of the important maintenance items:

Inflating your tires

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.

Use the recommended cold inflation pressure for optimum tire
performance and wear. Under-inflation or over-inflation may cause
uneven treadwear patterns.

Under-inflation is the most common cause of tire failures and
may result in severe tire cracking, tread separation or

⬙blowout⬙,

with unexpected loss of vehicle control and increased risk of injury.
Under-inflation increases sidewall flexing and rolling resistance,
resulting in heat buildup and internal damage to the tire. It also may
result in unnecessary tire stress, irregular wear, loss of vehicle control
and accidents. A tire can lose up to half of its air pressure and not
appear to be flat!

When weather temperature changes occur, tire inflation pressures also
change. A 10° F (6° C) temperature drop can cause a corresponding
drop of 1 psi (7 kPa) in inflation pressure. Check your tire pressures
frequently and adjust them to the proper pressure which can be found
on the tire label or certification label.

If you are checking tire pressure when the tire is hot, (i.e. driven more
than 1 mile [1.6 km]), never “bleed” or reduce air pressure. The tires are
hot from driving and it is normal for pressures to increase above
recommended cold pressures. A hot tire at or below recommended cold
inflation pressure could be significantly under-inflated.

To check the pressure in your tire(s):

1. Make sure the tires are cool, meaning they are not hot from driving
even a mile.

Note: If you have to drive a distance to get air for your tire(s), check
and record the tire pressure first and add the appropriate air pressure
when you get to the pump. It is normal for tires to heat up and the air
pressure inside to go up as you drive. Never “bleed” or reduce air
pressure when tires are hot.

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221