2004 GMC Canyon Owner's Manual - Page 350

Storing a Flat or Spare Tire, Jack and Tools Store the tire under the rear of the vehicle in the spare tire carrier. Use the art and text following to help you. {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. Notice: Storing an aluminum wheel with a flat tire under your vehicle for an extended period of time or with the valve stem pointing up may damage the wheel. Always stow the wheel with the valve stem pointing down and have the wheel/tire repaired as soon as possible. 1. Put the tire on the ground at the rear of the vehicle with the valve stem pointed down. 5-86