Tire wear

When the tread is worn down to 1/16th of an inch (2 mm), tires must be replaced to help prevent your vehicle from skidding and hydroplaning. Built-in treadwear indicators, or “wear bars”, which look like narrow strips of smooth rubber across the tread will appear on the tire when the tread is worn down to 1/16th of an inch (2 mm).
When the tire tread wears down to the same height as these “wear bars”, the tire is worn out and must be replaced.

See also:
Determining if the system is operational
The SRS uses a readiness light in the instrument cluster or a tone to
indicate the condition of the system. Refer to Warning lights and
chimes in the Instrument Cluster chapter. Routine maintenanc ...
Motorcraft part numbers
Refer to scheduled maintenance information for the appropriate
intervals for changing the spark plugs.
Replace the spark plugs with ones that meet Ford material and
design specifications for ...
Tires
Tires are designed to give many thousands of miles of service, but they
must be maintained in order to get the maximum benefit from them.
Glossary of tire terminology
• Tire label: A label showing ...
