Yeah, I guess John is right. The rim would have to be custom made, because the KH hub is 36 spoke. Then, a 36 spoke 12" rim would have the spokes nearly touching, so tensioning would have to be done from the outside of the rim. And the other guy had a point. Riding up hill would be very hard.
I have actually ridden a 12" like this, and it wasn’t that hard. I would seriously do this if I had a few hundred dollars to blow. I think it would be an awesome experiment.
no way i take it all back ! thats totally awesome !
I rode one of these once as well, and it was funny, i had a race with another guy, he won but he was half my size so he had an advantage… on flat land it was suprisingly easy, i managed to freemount first time!
and you would have to custom make the cranks because you wouldn’t be able to pedal with 127s.
the sun 20 uni also has something like 7 spokes, and a single walled rim. The tire has no traction compared even to a luna, and unless you wanted it to be rock ad you would bottom out all the time.
Also, not any people tuck to the full amount on a trials uni (so that your but is touching the tire. It wouldn’t even help if you couldn’t do that.
another thing, unless all of you trials is hop hop gap (which looks really bad), rolling lines would suck, especially skinnies.
and you wouldn’t be able to use metal pedals(not enough room)
I don’t have photo shop were do you get it? 
Touche
However, I can solve all of those problems. Switch the KH moment for Koxx Light 90mm hub+cranks, or try out Koxx re-enforced 110’s and see if those work.
Custom make the rim. It would cost you lots, but it could be done.
I don’t get your point here.
Skinnies would be fine if the cranks were in good proportion to the wheel. Unless you do rolling trials the uni would be fine. Anyway, rolling trials is better suited to 24", not even a 19" trials.
Why wouldn’t you have room for metal pedals? As long as you have 9/16 thread, it should be fine…
Would it be possible to put that kind of wheel/cranks on a coker frame? I think that would look really weird. Would it even be ridable?
Any size wheel will fit in a Coker frame, and the distance from the seat to the hub will be right. You could get a 12 inch rim built onto a decent hub and not bother buying a new frame, seat post and seat.
As for cranks: it is easy to get cranks down to about 80mm. Steel cranks are strong, and weight is less of an issue with very short cranks. As they are short, there is less risk of them bending.
I have briefly ridden a 12 inch unicyle. The novelty soon wears off.
With a smaller wheel you would be able to pedal more in your trials lines. The distance it takes to make a full rev on a 12" is smaller then on a 20". So instead of hopping forward on the 20" you could just ride forward on the 12". As Mikefule said, the cranks would be fairly strong because they are so short=less leverage.
Well, I bought 2 12" unicycles for my 3 year old girls (twins). Maybe when they learn to ride and out grow them, I will slap one of those tall seat posts on one of them. It might be a novelty unicycle, but would be good to bring to club practices and/or parades.
oooh i want it!
Thats what she said.
Mike 
yeah! why even have a wheel? ditching that could take off another couple pounds!
oh wait, some people like to roll places
why have a heavy seat, just have a handle
more weight saved
Why have a unicycle at all? Just walk on the rails.
my god, the boys got it
but relay i don’t see a point in such a small unicycle
laters
Dale
Why bother with legs?
that guy is awesome, he is crazy fast