FORD 2004 F-150 v.1 - Manual (Page 169)

Tires, Replacement Requirements
Do not use a size and type of tire and wheel other than that
originally provided by Ford Motor Company because it can affect
the safety and performance of your vehicle, which could result in an
increased risk of loss of vehicle control, vehicle rollover, and/or serious
personal injury or death.
Make sure all tires and wheels on the vehicle are of the same size, type,
tread design, brand and load-carrying capacity. If you have questions
regarding tire replacement, see an authorized Ford or Lincoln/Mercury
dealer.
If you nevertheless decide to equip your 4WD for off-road use with tires
larger than what Ford Motor Company recommends, you should not use
these tires for highway driving.
If you use any tire/wheel combination not recommended by Ford Motor
Company, it may adversely affect vehicle handling and could cause
steering, suspension, axle or transfer case failure as well as the increased
risk of loss of vehicle control.
Do not use “aftermarket lift kits” or other suspension modifications,
whether or not they are used with larger tires and wheels.
These “aftermarket lift kits” could adversely affect the vehicle’s handling
characteristics, which could lead to loss of vehicle control or rollover and
serious injury.
Tires can be damaged during off-road use. For your safety, tires that are
damaged should not be used for highway driving because they are more
likely to blow out or fail.
You should carefully observe the recommended tire inflation pressure
found on the safety compliance certification label attached to the left
front door lock facing or door latch post pillar. Failure to follow tire
pressure recommendations can adversely affect the way your vehicle
handles. Do not exceed the Ford Motor Company recommended pressure
even if it is less than the maximum pressure allowed for the tire.
Driving
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