Ford F-450 (2017 year). Manual — part 92

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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.

E168583

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.

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.

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.

*kPa: Kilopascal, a metric unit of
air pressure.

*PSI: Pounds per square inch, a
standard unit of air pressure.

*Cold tire 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 kilometers).

*Recommended inflation
pressure: The cold inflation
pressure found on the Safety
Compliance Certification Label
(affixed to either the door hinge
pillar, door-latch post, or the door
edge that meets the door-latch
post, next to the driver's seating
position), or 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.

Information Contained on the
Tire Sidewall

Both United States and Canada
Federal regulations require 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

H

I

J

K

L

M

A

B

C D

E

F

G

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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 from this example).