Ford 2003 Explorer Owner's Manual page 184

Maintenance and Specifications
Replacing tires
Replace the tires when the wear
band is visible. Due to exposure to
the elements and exhaust you
should replace the spare tire when
you replace the other tires.
Never mix radial bias-belted
tires, 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 effected 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,
load-carrying capacity and tread design 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
affect the accuracy of your speedometer.
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