shortest crank arms

I was thinking about a 12" uni.

What do you think the shortest crank arms that could be made would be?

How about the shortest practical crank arms?

The shortest cranks that could be made is 0mm. As for shortest practical length, come on, you’re talking about a 12" unicycle. Where does practical work into that?


I would shoot for something shorter than six inches :wink:

edit: Ok, maybe I’ll give a real reply. I would try using 89mm cranks.

Giraffe, or just like a regular uni? Standard axle or all custom, to allow you to go shorter? I’ve seen standard unicycles with wheels of 2" and smaller. Not easy to ride!

My 12" uni has 3.5" cranks. Those are the cranks that came with the kiddie bike it was built from. Shorter cranks would make it a little easier to ride, with the seat as low as I have it on mine. Also my pedals (the kiddie pedals that came with same bike; a little narrower than regular ones) hit the ground when you turn unless you really work to keep the uni upright.

I juggled clubs while riding it in my show the other day. Badly. My seat is about 16" off the ground.

89mm is fairly easy to obtain, I mean approaching the extreme of the pedals touching the axle, possibly with the diameter of each approaching zero. 89mm also comes standard on sun 12" unis.

The crank arms I’m talking about would probably be for a standard 20", however, without having too much leverage to get going.

John, I heard of the 2" unis and I just assumed they were assembled with chain drive…
but a standard build? wow.

I would definitely beg to ride one of those if I saw it at a convention :slight_smile:
How would you go about getting the parts? Machine them yourself?

My 12"-er has 3.5" cranks.

They do tend to hit the ground on turns, so, if getting new cranks I’d probably go smaller.

Don’t forget that 12"-ers need realy long seatposts if they’re for adults- mine’s around 17".

I’ll repeat myself— I’m talking about approaching the limit regarding crank length, without having too much leverage. On any size uni.

Would you like to repeat yourself with a little more background info? Are you planning to use a square taper axle, or custom build? You can go a lot shorter if you go custom. If you use standard parts you just need to leave a tiny bit of metal between the axle hole and the pedal hole. So what was your real question?

And a 12" uni does not need a long seat post. In fact I’d say that was a bit silly. There’s no point in being real comfortable or having good leg extension with a 12" wheel. It’s a silly setup, so it might as well look silly. That’s why I cut down the frame on mine to make it even lower than it was when I first got it. You can see it on top of my head in this picture (I think that was after I cut it down).

Here is Teresa Abrahams on hers. Not sure the exact wheel size, but it’s all handmade. There is also a video there of her riding it, but mostly it shows her spoofing my own “Mission Impossible” act I do when I ride my 12", which I must have done earlier in that same show… :stuck_out_tongue:

Is a helmet really necessary when riding a 3" unicycle?

with standard equipment, the limit is approximately 25mm, as this is half the diametre of the taper, plus half the diametre of the pedal spindle, plus a tiny bit of metal in between.

Thinner axles/spindles would allow this figure to come down.

There’s a video around of possibly Brian Macenzie riding a coker with 40mm cranks. He’s using more of a BC wheel style body movement to keep it balanced as the torque fomr the cranks is insufficient to make any sudden adjustments.

In one of Brian MacKenzie’s videos he shows the process of cutting down some cotterless (square taper) cranks and welding them back together to make 40mm cranks for a Coker. Here is Brian’s thread about the pygmy Coker cranks.

It depends what you’re doing with it. :slight_smile:

In her case, she’s spoofing my act, in which I roll out a piece of luggage and pull out:

  • A pair of sunglasses
  • A helmet
  • A pair of the world’s smallest traffic cones, at about 4" tall
  • And finally, the unicycle that goes with all of this

:slight_smile: this is very close to what i’ve been looking for.