Instead of paying $80 for a Green Machine (like stupid ol’ me), just copy down the serial # off the one on display at Toys R Us (it’s stamped onto the bottom of the frame). Then call Huffy and ask for a replacement wheel. They’ll ask for the serial # as proof of purchase. I think it’s around $25 and should include complete wheelset with tire and cranks.
However…I don’t think the GM hub is made to handle the forces of an adult unicyclist. Mine began slipping after a few hours of practice, like maybe the teeth or whatever inside the hub started breaking off, until it simply freewheeled in both directions, making the cranks useless (unless you put them on kangaroo style and make it a BC wheel as I assume Skippii has done[glad you found a use for it]). I haven’t bought a replacement yet, but good luck if you go this route, and let us know if yours breaks too, mine might have just been faulty.
I have 2, the best of which cost me almost nothing. It is a 16" wheel one that I found in a skip! It is the front wheel of one of those trike things that was trendie a few years ago. I just slotted the steerer put a seatclamp on it and a seatpost/seat and it was there.
They are not that hard to ride, great fun as well.
It’s collection only North Yorkshire, and I’m broke anyway, so I won’t be bidding, but I’ll be keeping an eye out for tricycles in skips. It sounds a reasonably simple conversion even for someone who failed tech GSCE… And I’d love to have one, it was seriously good fun trying Roger’s in Perth, although you definitely meet the floor a lot faster than off a normal unicycle.