Ford F-250 Super Duty (1999 year). Manual — part 49

Replacing the tires

Replace the tires when the wear
band is visible through the tire
treads.

When replacing full size tires, never mix radial bias-belted, or
bias-type tires. Use only the tire sizes that are listed on the

Certification Label. Make sure that all tires are the same size, speed
rating, and load-carrying capacity. Use only the tire combinations
recommended on the label. If you do not follow these precautions,
your vehicle may not drive properly and safely.

Make sure that all replacement tires are of the same size, type,
load-carrying capacity and tread design (e.g., “All Terrain”, etc.),

as originally offered by Ford.

Do not replace your tires with “high performance” tires or larger
size tires.

Failure to follow these precautions may adversely affect the
handling of the vehicle and make it easier for the driver to lose

control and roll over.

Tires that are larger or smaller than your vehicle’s original tires may also
affect the accuracy of your speedometer.

SNOW TIRES AND CHAINS

Snow tires must be the same size and grade as the tires you
currently have on your vehicle.

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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. If you need to use chains, it is recommended that steel
wheels (of the same size and specifications) be used as chains may chip
aluminum wheels.

Follow these guidelines when using snow tires and chains:
• Use only SAE Class S chains.
• 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.

• The suspension insulation and bumpers will help prevent vehicle

damage. Do not remove these components from your vehicle when
using snow tires and chains.

WHAT YOU SHOULD KNOW ABOUT AUTOMOTIVE FUELS

Important safety precautions

Do not overfill the fuel tank. The pressure in an overfilled tank
may cause leakage and lead to fuel spray and fire.

The fuel system may be under pressure. If the fuel filler cap is
venting vapor or if you hear a hissing sound, wait until it stops

before completely removing the fuel filler cap. Otherwise, fuel may
spray out and injure you or others.

If you do not use the proper fuel filler cap, excessive pressure or
vacuum in the fuel tank may damage the fuel system or cause

the fuel system to work improperly in a collision, which may result in
possible personal injury.

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Automotive fuels can cause serious injury or death if misused or
mishandled.

Observe the following guidelines when handling automotive fuel:
• Extinguish all smoking materials

and any open flames before
fueling your vehicle.

• Always turn off the vehicle before

fueling.

• Automotive fuels can be harmful

or fatal if swallowed. Fuel such as
gasoline is highly toxic and if
swallowed can cause death or
permanent injury. If fuel is
swallowed, call a physician immediately, even if no symptoms are
immediately apparent. The toxic effects of fuel may not be visible for
hours.

• Avoid inhaling fuel vapors. Inhaling too much fuel vapor of any kind

can lead to eye and respiratory tract irritation. In severe cases,
excessive or prolonged breathing of fuel vapor can cause serious
illness and permanent injury.

• Avoid getting fuel liquid in your eyes. If fuel is splashed in the eyes,

remove contact lenses (if worn), flush with water for 15 minutes and
seek medical attention. Failure to seek proper medical attention could
lead to permanent injury.

• Fuels can also be harmful if absorbed through the skin. If fuel is

splashed on the skin and/or clothing, promptly remove contaminated
clothing and wash skin thoroughly with soap and water. Repeated or
prolonged skin contact with fuel liquid or vapor causes skin irritation.

• Be particularly careful if you are taking “Antabuse” or other forms of

disulfiram for the treatment of alcoholism. Breathing gasoline vapors,
or skin contact could cause an adverse reaction. In sensitive
individuals, serious personal injury or sickness may result. If fuel is
splashed on the skin, promptly wash skin thoroughly with soap and
water. Consult a physician immediately if you experience an adverse
reaction.

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When refueling always shut the engine off and never allow
sparks or open flames near the filler neck. Never smoke while

refueling. Fuel vapor is extremely hazardous under certain conditions.
Care should be taken to avoid inhaling excess fumes.

The flow of fuel through a fuel pump nozzle can produce static
electricity, which can cause a fire if fuel is pumped into an

ungrounded fuel container.

Use the following guidelines to avoid static build-up when filling an
ungrounded fuel container:
• Place approved fuel container on the ground.
• DO NOT fill a fuel container while it is in the vehicle.
• Keep the fuel pump nozzle in contact with the fuel container while

filling.

• DO NOT use a device that would hold the fuel pump handle in the fill

position.

Choosing the right fuel

Use only UNLEADED FUEL. The use of leaded fuel is prohibited by law
and could damage your vehicle.

Do not use fuel containing methanol. It can damage critical fuel system
components.

Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based compounds containing MMT.

Repairs to correct the effects of using a fuel for which your vehicle was
not designed may not be covered by your warranty.

Octane recommendations

Your vehicle is designed to use
“Regular” unleaded gasoline with an
(R+M)/2 octane rating of 87. We do
not recommend the use of gasolines
labeled as “Regular” that are sold
with octane ratings of 86 or lower in high altitude areas.

Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily under most driving conditions while you are using fuel

87

(R+M)/2 METHOD

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