Unicycle wheelchair attachment

This may seem like a strange post, but I’m going to take a try at it anyway. I am new to the world of unicycles, but have been doing a bit of research, and hope you don’t find this post too crazy.

I am considering using a unicycle to attach as a third wheel to the front of a wheelchair for my partner. The reason I want to do this is to give the wheelchair a smoother ride on rough surfaces like brick and cobblestone streets, and also give the ability to use foot propulsion with pedals to go short distances on flat surfaces.

What I think would work is a street or trials unicycle with a longneck frame, a mountain bicycle stem and handlebars where the seat post would normally go on the frame, and a V-brake and lever. I’m also working on a solution to attach the unicycle frame to an adapter on the wheelchair.

I would like to use a fairly small wheel – 16 to 18 inch. I know that the bigger the wheel the faster it will go, but a big wheel will also make it difficult for manuevering and getting in/out of the wheelchair.

So my question is whether it is possible to use a 16 or 18 inch wheel in a 20 inch frame, and if possible even a bigger frame like the mountain frames at 24 inch?

BTW, I am in Europe and my brother is a mountain bike component engineer in Seattle. I know he can help me on the bike parts of this, but it’s the unicycle part that I want to get more input on. If anyone knows a good unicycle I can recommend to him to check out components, that would be helpful too.

I just realised that it might help if I posted a picture of what I am envisioning. This is a product marketed for wheelchairs, but without the option to pedal, and with a 16 inch wheel:

There are only 2 products that are on the market with pedal capability, but they are both much bigger and much more expensive (about $4000) than we want. Here is an example, with a 20 inch wheel:

You should be able to use a bigger frame for a smaller wheel.

Sorry for posting yet again, but for some reason I can’t edit my original post. What I meant with the following, was if someone knew a good “unicycle shop in Seattle”.

It would be pretty easy for a bike frame builder to put unicycle bearing holders on an ordinary bike fork, instead of the normal dropouts. Unicycle.com here in the US sells them. Then you wouldn’t need a custom solution for the handlebars or headset, you would just put the unicycle wheel in the bike fork. A disc brake wheel would make it easy to use mismatched wheel and fork size.

How would you avoid having the wheel hit your legs as you steer? I notice that the one pictured has the pedals behind the wheel so that it doesn’t have a problem.

Is your intent for the occupant of the wheelchair to do the pedaling? I don’t want to assume that, though your examples seem built for that.

The $4000 model probably has a more ergonomic body position than you would get pedaling the wheel directly. Also it will clearly go faster. If you direct-pedal a 16-18" wheel, all you’re going to be is slow. Regular hand propulsion (assuming full use of arms) would be faster.

Steering: While you can put an angle between the seatpost/handlebar and the fork, any way you work it, large turns of the wheel will interfere with pedaling. For the chair to be useful, you will need to target it either for speed, or for maneuverability/fitting small spaces. It probably won’t be able to be good at both.

For parts, most bike shops don’t stock much in the way of unicycles, and even less (basically nothing) in terms of parts. But if you see something you like at Unicycle.com, you can probably find a Unicycle.com dealer in your area to handle the ordering. I recommend sticking with a 20" wheel. Lots more choices in tires and rims, and it will be a little faster.

My company works with lots of people in wheelchairs. I would love to hear about anything you build, and see pictures. Please keep us posted. Good luck!

Couple of links that may be useful:



Try Gregg’s Cycles. They are in Bellevue and the U-District, maybe elsewhere as well. If they can’t do the work they will likely know someone who can. The closest unicycle.com affiliated store I know of is Serious Juggling in Portland, although they are strictly retail. Good luck!

I thank you all for your input. You are giving me a lot to think about.

I’m at the beginning phase of looking to build this. My partner has hemiplegia/hemiparesis (one sided paralysis) caused by strokes during surgery for twisted intestines. He is overall fit, and loves to cycle (he is Dutch!), and I’m trying to find good solutions that fit his needs.This would not be for going fast – think walking speed.

We have some budget from the government left over from buying a really good wheelchair. I would like to use that to buy the basics to move on with this project, which I think is a good unicycle wheel, hub, crank and pedals.

I really like the idea of using unicycle bearing holders on an ordinary bike fork, instead of the normal dropouts. I’m rethinking all of this based on that.

I’ve made a very “thinking out loud” with very rough ideas web page so I could discuss things with my bike engineer brother. If anyone is inclined, here is a link.

You guys are great for jumping in with us on this. I am a bit short on time now, but as we move forward, I hope you don’t mind a few more questions.

Thanks for the suggestion blueharmony. It looks like Gregg’s Cycle only carries Troker’s from their website, and I did not see many components. Do you know of any shops in Seattle that have some of the higher end components also?

This is going to be a one-off labour of love to build this, and the labour will be far more than the component costs. It would be great if my brother could go into a shop and look and feel different hubs, cranks, etc.to see how they might work with MTB components.

If that is not possible, and any of you are in Seattle and want to show your kit, I’m sure there would be some nice local brewed beer as a thank you.

Ah, vandaar! Doe hem de groeten van een fellow Dutchman.

Depending on his physical abilities, why not something more “cyclisty”? Like one of these. If he has full use of one side, this would probably be much more fun if the idea is to go places. The wheelchair version would be only as fast as a unicycle of that wheel size, which would be slow.

I think the original post mentioned that the emphasis is on small size, maneuverability and short distances. Most recumbent tricycles wouldn’t qualify.