Ford Excursion (2005 year). Manual — part 33

• Narrower — to provide greater

maneuverability in tight spaces,
particularly in off-road use.

As a result of the above dimensional
differences, SUV’s and trucks often
will have a higher center of gravity
and a greater difference in center of
gravity between the loaded and
unloaded condition.

These differences that make your
vehicle so versatile also make it
handle differently than an ordinary
passenger car.

INFORMATION ABOUT UNIFORM TIRE QUALITY GRADING

New vehicles are fitted with tires
that have a rating on them called
Tire Quality Grades. The 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
These Tire Quality Grades are determined by standards that the United
States Department of Transportation has set.

Tire Quality Grades apply to new pneumatic tires for use on passenger
cars. They do 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 or limited production tires as defined in
Title 49 Code of Federal Regulations Part 575.104(c)(2).

U.S. Department of Transportation-Tire quality grades: The U.S.
Department of Transportation requires Ford to give you the following
information about tire grades exactly as the government has written it.

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

Tires, Wheels and Loading

134

and one-half (1 1/2) 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 significantly from the
norm due to variations in driving habits, service practices, 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. 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.

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 dissipate 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 temperature can lead to
sudden tire failure. The grade C corresponds to a level of performance
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.

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.

TIRES

Tires are designed to give many thousands of miles of service, but they
must be maintained in order to get the maximum benefit from them.

Glossary of tire terminology
• Tire label: A label showing the OE (Original Equipment) tire sizes,

recommended inflation pressure and the maximum weight the vehicle
can carry.

Tires, Wheels and Loading

135

• Tire Identification Number (TIN): A number on the sidewall of

each tire providing information about the tire brand and
manufacturing plant, tire size and date of manufacture.

• Inflation pressure: A measure of the amount of air in a tire.
• Standard load: A class of P-metric or Metric tires designed to carry a

maximum load at 35 psi [37 psi (2.5 bar) for Metric tires]. Increasing
the inflation pressure beyond this pressure will not increase the tire’s
load carrying capability.

• 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 tire’s load carrying capability.

• kPa: Kilopascal, a metric unit of air pressure.
• PSI: Pounds per square inch, a standard unit of air pressure.
• Cold inflation pressure: The tire pressure when the vehicle has

been stationary and out of direct sunlight for an hour or more and
prior to the vehicle being driven for 1 mile (1.6 km).

• Recommended inflation pressure: The cold inflation pressure found

on the tire label located on the B-Pillar or the edge of the driver’s
door.

• 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.

INSPECTING AND INFLATING YOUR TIRES

Safe operation of your vehicle requires that your tires are properly
inflated. Remember that a tire can lose up to half of its air pressure
without appearing flat.

Tires, Wheels and Loading

136

Every day before you drive, check
your tires. If one looks lower than
the others, use a tire gauge to check
pressure of all tires and adjust if
required.

At least once a month and before
long trips, inspect each tire and
check the tire pressure with a tire
gauge (including spare). Inflate all
tires to the inflation pressure
recommended by Ford Motor
Company.
Inspecting your tires
Periodically inspect the tire treads for uneven or excessive wear and
remove stones, nails, glass or other objects that may be wedged in the
tread grooves. Check for holes or cuts that may permit air leakage from
the tire and make necessary repairs.
Also inspect the tire sidewalls for cuts, bruises and other damage. If
internal damage to the tire is suspected, have the tire demounted and
inspected in case it needs to be repaired or replaced. For your safety,
tires that are damaged should not be used because they are more likely
to blow out or fail. Tires can be damaged during off-road use, so
inspection after off-road use is also recommended.
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!

Tires, Wheels and Loading

137