Small Foldable Unicycle Design

I have to design and eventually build a small, foldable unicycle that could be stored in an average school backpack. I have ridden a unicycle for a few years now and I still ride very often. I am thinking about using a 16" wheel and 4" folding cranks with a collapsible frame. I am very open to changing the design and I would love to hear any changes that you think I should make or any design ideas that you have.

A very small giraffe would be interesting. Make the wheel 12", but gear it up by putting a larger-diameter sprocket between the cranks.

Sounds like a great idea! I’m wondering if 16" is the best size. Even with gearing to compensate for the small wheel size it seems like pedal strikes would be a problem during tight turns. What style of riding would the unicycle be for?

This sounds a lot like a penguin uni.

Wheel Size?

It’s just for street riding, no tricks or anything fancy. just meant to be very portable. what size wheel would you recommend?


This is a 19" penguin compared to a 36er. (geared up to a 40") It will fit in a 28-29" suitcase, and takes up about half of it.

Realistically, all you’re going to fit in a basic backpack without completely disassembling it would be a 12". Jakob came up with a quick release frame, but last I heard it was still a prototype. You still have the issue of the saddle being WAY too low.

I think strapping something to the outside of a bag would be the best option for a backpack style. I would recommend a 16" with short cranks (90mm) for speed if you’re using it for any kind of transportation, even walking speed. I would also look into folding pedals that are used on folding bicycles (brompton and bike friday and the like). You can cut most frames down so they only have around 2-3" of seat tube left, but at some point you need the saddle height to be high enough that it’s comfortable. A smaller wheel means a longer seatpost.

Depends on where you are, but often times a uni is overlooked if you’re rolling it around on busses, around a campus, even in a shopping center as long as you’re not on it, or throw it over your shoulder. Personally I would just take a standard 20" uni and sling it over the shoulder.

Great Ideas

Thanks I’ll look into the pedals, as for the frame I already have a design that can get plenty of height and then fold back down to almost only the size of the wheel. I should have mentioned that I will be 3D modeling and welding up my own frame. Its not that I am going to carry it in a backpack, its just that that is a good size to have as a goal for a uni that is very transportable and storable. Thanks for the great ideas.:slight_smile:

Fun project!
For the pedals, you can also look at the MKS EZY pedals, they can be removed and stored in the little pouch that they came with.

that yellow penguin is wonderful