2008 GMC Acadia Owner's Manual - Page 398

Storing a Flat or Spare Tire and Tools Storing the Spare Tire {CAUTION: Storing a jack, a tire, or other equipment in the passenger compartment of the vehicle could cause injury. In a sudden stop or collision, loose equipment could strike someone. Store all these in the proper place. To store the spare tire: 1. Lay the compact spare tire near the rear of the vehicle with the valve stem down. 2. Reinstall the plastic spare tire heat shield on the compact spare tire. 3. Slide the cable retainer through the center of the wheel and start to raise the compact spare tire. Make sure the retainer is fully seated across the underside of the wheel. 4. When the compact spare tire is almost in the stored position, turn the tire so the valve is toward the rear of the vehicle. This position helps when checking the air pressure in the compact spare tire. {CAUTION: The underbody-mounted spare tire needs to be stored with the valve stem pointing down. If the spare tire is stored with the valve stem pointing upwards, its secondary latch will not work properly and the spare tire could loosen and suddenly fall from your vehicle. If this happened when your vehicle was being driven, the tire might contact a person or another vehicle, causing injury and, of course, damage to itself as well. Be sure the underbody-mounted spare tire is stored with its valve stem pointing down. 5-84