I couldn't find much on the internet about cutting a tyre in half, mainly how not to do it. Having bought an oscillating tool not long ago it had to be a contender. I used a wood and metal blade as I knew there would be some metal reinforcement in the tyre and hoped the blade would be string enough to cut through them. I started off by marking where I wanted to make my cuts and scored the tyre with the blade so I had a good line to follow. Putting the oscillations on max I started the cut, it was pretty tough going as most of the reinforcement is located near the rim. I found the best way for me was to cut with the tool for a bit and then bend the tyre by hand by the cut which seemed to snap some of the broken steel. After a while I got through this heavily reinforced section the rest of the tyre wasn't too bad. Be warned though the cutting does melt the rubber and produce some fumes so do this bit outside.