Ford Super Duty (2017 year). Manual — part 92

Utility vehicles and trucks handle
differently than passenger cars in the
various driving conditions that are
encountered on streets, highways and
off-road. Utility vehicles and trucks are not
designed for cornering at speeds as high
as passenger cars any more than low-slung
sports cars are designed to perform
satisfactorily under off-road conditions.

Study your owner's manual and any
supplements for specific information about
equipment features, instructions for safe
driving and additional precautions to
reduce the risk of an accident or serious
injury.

Four-wheel drive system

(If Equipped)

WARNING

Do not become overconfident in the
ability of four-wheel drive vehicles.
Although a four-wheel drive vehicle

may accelerate better than a two-wheel
drive vehicle in low traction situations, it
won't stop any faster than two-wheel drive
vehicles. Always drive at a safe speed.

A vehicle equipped with four-wheel drive
(when selected) has the ability to use all
four wheels to power itself. This increases
traction which may enable you to safely
drive over terrain and road conditions that
a conventional two-wheel drive vehicle
cannot.

Power is supplied to all four wheels
through a transfer case or power transfer
unit. Four-wheel drive vehicles allow you
to select different modes as necessary. For
information on transfer case operation and
shifting procedures, See Four-Wheel
Drive (page 210). For information on
transfer case maintenance, See
Maintenance (page 320). You should
become thoroughly familiar with this
information before you operate your
vehicle.

On some four-wheel drive vehicles, the
initial shift from two-wheel to four-wheel
drive while the vehicle is moving can cause
a momentary clunk and ratcheting sound.
These sounds are normal and are not
cause for concern.

For four-wheel drive vehicles, a spare tire
of a different size other than the tire
provided should never be used. A dissimilar
spare tire size (other than the spare tire
provided) or major dissimilar tire sized
between the front and rear axles could
cause the four-wheel drive system to stop
functioning and default to front-wheel
drive. See Using Four-Wheel Drive (page
210).

How your vehicle differs from
other vehicles

Sport utility vehicles and trucks can differ
from some other vehicles in a few
noticeable ways. Your vehicle may be:

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•

Higher - to allow higher load carrying
capacity and to allow it to travel over
rough terrain without getting hung up
or damaging underbody components.

•

Shorter - to give it the capability to
approach inclines and drive over the
crest of a hill without getting hung up
or damaging underbody components.
All other things held equal, a shorter
wheelbase may make your vehicle
quicker to respond to steering inputs
than a vehicle with a longer wheelbase.

•

Narrower - to provide greater
maneuverability in tight spaces,
particularly in off-road use.

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As a result of the above dimensional
differences, Sport utility vehicles 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.

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TIRE CARE

Information About Uniform
Tire Quality Grading

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Tire Quality Grades apply to new
pneumatic passenger car tires.
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 passenger car tires.
They do not apply to deep tread,
winter-type snow tires,
space-saver or temporary use
spare tires, light truck or LT type
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 ©)(2).

U.S. Department of
Transportation Tire quality
grades: The U.S. Department of
Transportation requires Ford
Motor Company 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 and one-half (1
½) 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

WARNING

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.

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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 A B C

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.

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. 139. Grades B and A
represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law.

Glossary of Tire Terminology

*Tire label: A label showing the
original equipment tire sizes,
recommended inflation pressure
and the maximum weight the
vehicle can carry.

*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. Also referred
to as DOT code.

*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 set
pressure. For example: For
P-metric tires 35 psi (2.4 bar) and
for Metric tires 36 psi (2.5 bar).
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 42 psi
(2.9 bar). Increasing the inflation
pressure beyond this pressure will
not increase the tire’s load
carrying capability.

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