Weird okay. I don't actually use Kyosho shoes, I have a friend in canada who CNC machines shoes and I use his ones. When I tried to fit his shoes on my Kyosho flywheel, I had to spend some serious time turning them on the pins to get them to fit on. But they went straight on to all my other flywheels. (ofna, hot bodies, all 2.5mm) Maybe the Mugen pins are 2.6mm too? who knows.