Tire Iron BeadBrakR slide show - BestRest
I put my knees on the rubber tire.  This compresses the tire, and allows the bead to move into the CAVITY of the rim.  If you don't do this process, removing the tire will be difficult or IMPOSSIBLE

I put my knees on the rubber tire. This compresses the tire, and allows the bead to move into the CAVITY of the rim. If you don't do this process, removing the tire will be difficult or IMPOSSIBLE