FORD 2003 F-150 v.1 - Manual (Page 254)

Replacing the tires
Replace the tires when the wear
band is visible through the tire
treads. Due to exposure to the
elements and exhaust you should
replace the spare tire when you
replace the other tires.
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 handling may be affected which can lead to loss of vehicle
control, vehicle rollover and/or personal injury.
Make sure that all replacement tires are of the same size, type,
speed rating, load-carrying capacity and tread design (e.g., “All
Terrain”, “Touring”, etc.), as originally offered by Ford.
Do not replace your tires with “high performance” tires or larger
size tires.
Failure to follow these precautions, your vehicle handling may be
adversely effected which can lead to loss of vehicle control,
vehicle rollover and/or personal injury.
Tires that are larger or smaller than your vehicle’s original tires may also
affect the accuracy of your speedometer.
Maintenance and Specifications
254