Hi Jon

I know the feeling! Chip uses car tyre rubber and that was a nightmare to cut let alone a lorry tyre.

I too tried a jigsaw with various blades, angle grinder, hacksaw etc.

I know you have tried this but I found the reciprocating saw the best with good quality fine tooth blades.

The stainlees steel strands though are pigs to get through and really blunt the blades rapid.

It took me hours to cut 4 tyres for our wheels and they are only about 8 inch diameter, yours I know, are a bit bigger!

Good luck and if you come up with a good method let me know.

Tom