Jeep 2009 Grand Cherokee - Owner Manual - Manual (Page 343)

These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 in (2 mm). When the indicators appear in
two or more adjacent grooves, the tire should be re-
placed.
Many states have laws requiring tire replacement at this
point.
Life Of Tire
The service life of a tire is dependent upon various
factors including but not limited to:
• Driving style
• Tire pressure
• Distance driven
WARNING!
Tires and the spare tire should be replaced after six
years, regardless of the remaining tread. Failure to
follow this warning can result in sudden tire failure.
You could lose control and have an accident resulting
in serious injury or death.
1 — Worn Tire
2 — New Tire
STARTING AND OPERATING 341
5