Tire Spinning; Tread Wear Indicators - Jeep 2009 Grand Cherokee Owner's Manual

340 STARTING AND OPERATING
WARNING!
The limited-use spare tires are for emergency use
only. Installation of this limited-use spare tire affects
vehicle handling. With this tire, do not drive more
than 50 mph (80 km/h). Keep inflated to the cold tire
inflation pressure listed on either your tire placard or
limited-use spare tire and wheel assembly. Replace
(or repair) the original tire at the first opportunity
and reinstall it on your vehicle. Failure to do so could
result in loss of vehicle control.

Tire Spinning

When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle's wheels above 35 mph (55 km/h).
WARNING!
Fast spinning tires can be dangerous. Forces gener-
ated by excessive wheel speeds may cause tire dam-
age or failure. A tire could explode and injure some-
one. Do not spin your vehicle's wheels faster than
35 mph (55 km/h) when you are stuck, and do not let
anyone near a spinning wheel no matter what the
speed.

Tread Wear Indicators

Tread wear indicators are in the original equipment tires
to help you in determining when your tires should be
replaced.