Chevrolet Spark EV 2014 Owner's Manual page 280

Replace the tire if:
The indicators at three or
more places around the tire
can be seen.
There is cord or fabric
showing through the tire's
rubber.
The tread or sidewall is
cracked, cut, or snagged
deep enough to show cord or
fabric.
The tire has a bump, bulge,
or split.
The tire has a puncture, cut,
or other damage that cannot
be repaired well because of
the size or location of the
damage.
If the vehicle has non-directional
tires, they should be rotated
every 12 000 km/7,500 mi. See
.
Tires are rotated to achieve
uniform wear for all tires. The
first rotation is the most
important.
Anytime unusual wear is
noticed, rotate the tires as soon
as possible, check for proper tire
inflation pressure, and check for
damaged tires or wheels. If the
unusual wear continues after
the rotation, check the wheel
alignment. See
and
.
Directional tires should not be
rotated. Each tire and wheel
should be used only in the
position it is in. Directional tires
will have an arrow on the tire
indicating the proper direction of
rotation or will have left or
right molded on the sidewall.
Different tire sizes should not be
rotated front to rear.
Use this rotation pattern if the
vehicle has different size tires
on the front and rear and they
are non-directional.