Chevrolet 2006 Express Van Owner's Manual page 328

3. Turn the ratchet counterclockwise to lower the
spare tire to the ground. If the spare tire does
not lower to the ground, the secondary latch
is engaged causing the tire not to lower.
See Secondary Latch System on page 5-80.
5-74
4. When the tire has been lowered, pull the tire toward
you so you can reach the tire retainer and pull it up
through the wheel opening.
If you have a vehicle which was completed from a cab
and chassis, refer to the information from the body
supplier/installer.
The spare tire is a full-size tire, like the other tires on
your vehicle.