Impossible wheel with frame and seat, does it exist?

So lately I’ve been thinking about getting myself an ultimate wheel or even an impossible wheel.
In theory the ultimate wheel is just a uni without the frame, but the impossible wheel is different.
It’s easy to make one from a BMX front wheel, but what if you would convert an existing uni to an impossible wheel with frame? This would allow for much better control (you could even mount a brake).
Does it exist already?

It should be fairly simple to make one either by mounting pegs (bmx) on the axle or even easier, just take off one of the crank arms, rotate it 180 degrees and mount it again.

All that you need to actually start rolling is a freewheel, but I think it can be awesome to ride it!
It would be like coasting on a freewheel, but then with both pedals below at the same time for better balance (lower point of gravity).

Do they exist already?

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Why not just use a bicycle fork? Way cheaper and it should work just as well for an IW.

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So although I think this is probably a discussion for the freewheel megathread as a freewheel variation (perhaps someone can merge it), I think I get what you’re saying.

Really what you’d want would be the cranks/footplates to be affixed to the axle so that they couldn’t rotate independently. That would possibly give you marginally more control and allow your feet to vary your centre of gravity forwards and backwards slightly.
In reality I suspect that the lowering of the centre of gravity would be so negligible to not be noticeable, and the effect of being able to move it with your feet would also not be noticeable/wouldn’t be a thing.

Easy enough to test with a modified BMX front axle (peg freewheel) and some purchased or DIY footplates.

What’s still interesting to me is the prototype UDC BC wheel prototype with disk brake - whatever happened to that @rogeratunicycledotcom ?
I forgot that it was a thing until now.

I rode an “impossible wheel” with a frame. It was BMX front wheel with pegs mounted onto a unicycle frame with the use of a stack of some large washers that the bearing clamps mounted onto, fairly simple. Like an impossible wheel, you would have to give it momentum by walking/running, then jumping onto it.

Found it fun to play around with for a bit, but nothing I would want to own. The fact that the platforms are under the axle on a BC/impossible wheel adds a lot of stability, so the seat doesn’t add that much.


I presume that stability advantage would disappear as soon as you added the seat if you actually sit on it.

Yes, but having a seat adds a different kind of stability.

I haven’t exactly put that much time into it, but to me, the seat didn’t suddenly open up any possibilities that a “regular” BC wheel doesn’t have. If you added a brake maybe, but when you go that far, you may as well build a freewheel.

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Forgot about this old thread by @waaalrus

That might be a better merge.

@waaalrus just uploaded some old peg unicycle stuff :

I have never tried an impossible wheel, but from my freewheeling experience, I can imagine that a unicycle with pegs lower than the axle would be more stable, it is probably the machine that would make it easier to do very long coasts (severals km?). When I practise freewheel, I can coast up to 350m, I don’t have a spot to do more (note that on a normal unicycle, I don’t do 10m…).

Anyway, on a freewheel unicycle, although it is easier to balance with your buttocks off the saddle, I think that putting a little weight on the saddle can be useful. On a flat road it is less tiring and with experience you can certainly use this support to better control your balance.

Well I say that, but I prefer pedal-operated machines, at least we can keep going when the road climbs.


Surely that’s a limit imposed by where you’re riding rather than the distance itself?

Or do you find yourself tired to a point of not being able to continue to coast after around that distance?

The impossible wheel shown in waaalrus’s video would be extremely easy to convert over to foot platforms below the axle. What I would do personally is look for some scrap aluminum of sufficient strength that is already bent to 90 degrees, then simply cut two pieces of it that could bolt to the sides of the fork, and extend below the axle where the 90s would extend to the sides and serve as foot platforms. Aluminum would be my preferred choice of metals because its light and can be cut quickly with common power saws.

If I couldn’t find any aluminum that was already prebent, it wouldn’t be too much of a task to fabricate similar footrests out of 1/8" aluminum plate. There would probably need to be some L brackets to reinforce it, but still an easy job.

It is still in our loft, it was very cool and easy to use. I should bring it out to play some time

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I’d love to have a go on it when you do!

I put my BC plates on as a test when I set up my peg unicycle (based on a drift trike front end). I don’t remember exactly why I didn’t like them. I may have felt that they were too likely to cause (body or property) damage. The pegs make a stable enough base. I only regret not recording a video in a skate park. Photo from 2015-03-13:

Peg Unicycling


I think what would really be interesting would be an IW with the bc plates and a handlebar instead of a seat. I would think that would allow you to really aggressively change your center of mass relative to the wheel.

i forget who made this thing. kinda similar to what you were thinking @Duff

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I’m thinking someone with a lot more athletic talent than I have could really tear up a skate park with that.

It’s not impossible. That was never a good name or definition for this type of uni. Better to pick a less-specific superlative, such as a variation of “ultimate” to go with the idea of the Ultimate Wheel. Like the Spectacular Wheel. Or the Massively Difficult Wheel. :smiley:

In the US we called them BC Wheels. This comes from the newspaper comic strip “B.C.” by Jonhnny Hart. A cave-person themed strip, it featured many moments in the life of Thor, the guy who (usually) rode his solid stone wheel with the wood axle. But that name is only meaningful to people familiar with the comic. Even though Johnny Hart gave the unicycling community a nod from time to time, such as giving permission (informally perhaps) for images of Thor to be used in promoting unicycle events. Also, unicyclist Chaz Marquette performed in one or more live-action TV commercials for Monroe Shock Absorbers (for cars), in which he rode a single, stone wheel. :slight_smile:

Also I would contend that a BC Wheel with a frame and seat would not be a BC Wheel; it would be a more “evolved” version of Thor’s invention. The advantage of having a seat on one of those is, primarily, so you can sit down. Who wants to stand all day?

And while I’m on that subject, this is the reason I have absolutely no interest in an electric unicycle that forces you to stand up the entire time you use it. The only advantage to a standing uni is to make the vehicle smaller, which is great for storage and bringing it on the train or bus. If I get one, it’s going to be one with a seat. I like this one I got to ride in Spain:


Is that the avatar of @As_Stupid_Does ?

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For a decade I’ve had it in my head that it was from The Flintstones, but from a quick search it seems all of the unicycles in that had seats and pedals.

In the UK I think we also call them BC wheels (or at least I do :grin: ).