Ford 2003 Mustang Owner's Manual page 163

Four tire rotation
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.
Maintenance and care
163