[motto]

I have found that old hardened tyres are relatively easy to cut through with a bow saw, it's like sawing wood.
One of the problem tyres I encountered was a run-flat with sidewalls about 1-1/2" thick. It was on a Dodge Weapons Carrier and would not hold air. I travelled a thousand miles on it before replacing it.
The only way to remove it was to cut it off. First off I cut a wedge shaped piece out of it with two cuts starting about 3" apart and coming together near the bead.
Opposite that I removed another wedge but didn't bring the cuts together, I chewed the fabric and rubber out between them with an electric drill. This left a gap that I used to chisel through the wires.
Lastly I hooked chains on either side of the cut out and pulled the tyre open which I could do because of the wedge section removed earlier.
The whole operation didn't take long and wasn't very strenuous.
One of the wedge sections removed was laying around for years as a curiosity. It's probably still around somewhere.

David