I'm definitely curious about turning, or more precisely steering. I just assumed there was a flywheel ala bb8 for the pivot motion.
Edit: OK, I see the rings and it definitely looks like one is moving in one direction and the other the opposite direction. So tank drive seems plausible. If that's not the mechanism, I don't see much point in allowing the ring to move independently of both the central tire and the outer hub (both are static when it's turning, whereas the rings aren't)
Edit: OK, I see the rings and it definitely looks like one is moving in one direction and the other the opposite direction. So tank drive seems plausible. If that's not the mechanism, I don't see much point in allowing the ring to move independently of both the central tire and the outer hub (both are static when it's turning, whereas the rings aren't)