HiTechnic have started selling the Rotacaster wheels now as well. That’s great news for people who live State-side. Now you won’t have to worry about US customs intercepting your nice wheels and using them for something themselves.
HiTechnic is selling them in packs of two and you can get right here: [LINK].
They plan to have cool models up on their Models page soon, so make sure you keep an eye on there! If you don’t want to wait and you have a set of 4 of those wheels already, I can heartily recommend you make the IR RC Kart with them, it’s a serious drift-fest. I made one ages ago and it’s always a big hit at the LEGO events, kids (young ones and adult ones) love playing with it.