>>1157765I don't think it'll work with a retro direct because the teeth would be on the wrong side during backpedaling unless the belt was made doublesided. I do see it working with a kickshift. I also read you could pair it with a Schlumpf speed drive. Time for some armchair design what the fuckery...
SA S2 Kickshift + Schlumpf Speed Drive = cableless 4 speed belt drive
SA S3X + compatible belt drive cog + Schlumpf Speed Drive = 6 speed fixed gear belt drive
Schlumpf speed drive + Rohloff 14 speed hub = 28 speed belt drive