Ford 1997 Aerostar Manual page 255

If your vehicle has aluminum wheels, you may
demount the full size, non-temporary spare
tire (if so equipped) and remount on an
aluminum wheel to rotate the spare tire into
your vehicle's rotation pattern. Rebalance the
wheel.
You may discover uneven outside shoulder wear
on your vehicle's front radial tires if you drive
often in the city and turn frequently around
curbs. You can extend the life of your front tires
by remounting them so the outside of the tire
faces inside on the wheel rim.
Replacing the Tires
Replace any tires that show wear bands. When
your tire shows a wear band, it has only 1/16
inch (2 mm) of tread left.
Wear band
Because your vehicle's tires may wear unevenly,
you may need to replace them before a wear
band appears across the entire tread.
Your wheels and tires are match-mounted for
improved ride. Before you begin to repair a tire,
mark the wheel and tire so that they are
properly aligned when remounted. This will
ensure that the tires will continue to give you
the same ride level.
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