I'd suggest welding a subsoiler replacement tooth to the 2" square tube to act as a wedge between the tire bead and the wheel. The shape of that item is almost identical to the duck bill hammer head we used to use to break down big rig beads. Use the front end loader bucket tilt cylinder to get the angle right before lowering the bucket to break the bead.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!