Building a tandem uni: Two people on one wheel?

Okay, this is probably a horrible idea, but then, I thought building my high-speed geared giraffe was, too, and it worked out pretty darn well.

I was thinking of something were two people would ride side by side, with their cranks connected by a single axle with a wheel in the middle. Obviously, it would have to be some form of a short giraffe to get the axle below the cranks, but it could be shorter than my HSGG, where the bottom bracket has to be above the top of the wheel.

Main problems I see right now are that the frame and wheel would have to be very strong to support ~ 300 pounds, and that it would be really hard to ride and steer–but hey, that last part never stopped us unicyclists, did it?

Any opinions or suggestions would be greatly appreciated. I’d be building this for an MS150 charity ride. I don’t want to do an additional-wheeled thing like those kid’s bike attachments that someone here clamped onto the back of a unicyled.


sounds like fun , the people would have to be about the same weight though or it would tip over like a see-saw

I dont know about the thing with the wheel in the middle… Wouldnt each rider have to weight the same?

What about a tandem where its stacked. Somehow one rider is above the other…

You mean something like this…

Yep, pretty much, but I was hoping for side to side rather than back to front.
I’d thought about doing over/under as well, but I just don’t see that being a good idea.

I think as long as the weights are close and there isn’t much distance between the riders, it shouldn’t be a problem. I mean, I can ride okay carrying 20-30 pounds in one hand to the side. As long as we swap sides every few miles, we should be okay.

It could actually be done without any chains. Have a look at the pedal configurations on a paddle boat. They have one continuos axle with two sets of pedals. The hard part would be coming up with a frame that didn’t get in the way of legs.

I sure would love to have the honor of riding that thing with you, if you do go ahead and construct one… especially through the streets of NYC :smiley: (if you were up for it)!

Good luck!

It’s been done and has been ridden by asians. Search…

pic token on EJC in Rotterdam, at the booth of Semcycle, who made it.

Later and elsewhere ive been riding that one succesfully with a girl from Bruxelles, but facing each other was a requirement.

Re: Building a tandem uni: Two people on one wheel?

On Mon, 13 Feb 2006 22:45:13 -0600, leo wrote:

>but facing each other was a requirement.

Why? It looks from the pic that both riders could ride forward.
(And you make it sound like facing this girl was a bad thing.)

cause without eye-contact it simply was impossible to ride it.

No, I don’t. But you make it sound like her back looked better than the front, while I explicitly mentioned she was from Belgium, as indication of her appearance.

Anyway, further I remember mounting it was a funny part to. Now I did do acrobatics on unicycle before -so I was aware of the forces it takes-. Also we holded each other arms, which may have been a form of communication to.

do you mean to say that side by side might be too difficult to ride?

I have wondered about taking two unicycles the same, sitting them side by side, then ‘bolting’ the two inside cranks together - I suppose technically that’d make it a bike, but I think it’d still be fun.

i ahve actually seen a tandem uni, it had one person in front of the other, not side by side, and the cranks were linked by chains to the gear

I have too, there’s a picture of it, in this thread.

Seriously though, sounds like a really fun thing to do! Maybe with a little practice you can do it without eye contact, though if I’d be sitting opposite Leo’s Belgian girl that might not be a priority.

Does anybody have any film of people riding one of these tandems? I’ve seen a still picture, but it would be good to see how well people can ride them. I would think turning would be pretty interesting…

I’ve seen a sociable tandem ridden by a father and his daugter, who appeared to be about 10 years old. It just tilted a bit to one side.

But that’s a two-wheeler. Here’s my take on a side-by-side unicycle tandem:

First, I’ve seen two other types. I’ve seen Steve McPeak and a partner ride a stacked tandem giraffe on a high wire (on TV). The top rider basically does all the work, because the bottom rider can’t feel much of the balance. So I get the impression that she kind of keeps light pressure on the pedals and tries to minimize interference rather than supply her share of the power. This is probably the easiest type of two-person unicycle to ride.

Second I’ve seen one like the one pictured above. Ken Fuchs built it and brought it to a USA convention in the mid-90s. I watched him have several goes at it with Sem Abrahams. They were both highly skilled and experienced riders, but it seemed clear that they would probably need a few hours of practicing together before they could ride it consistently. I did see them go several feet, but I think turning was, at that point, out of the question. It also worked for one rider (Sem) to be the main driver while the other one stayed relatively still (not counting feet) and did not also try to control things.

I think the hardest part about riding the tandem above would be steering. The front/back balance is probably the easier part. So if you put the seats on the sides, controlling side-to-side balance will be much, much harder. Because the wheel won’t pivot under either rider, they will have to develop a different “flailing” motion to push themselves forward or back in relation to the wheel’s pivot point.

At the very least, it should make for some interesting video! :slight_smile:

I never heard of such a thing. I’d love to find out more. Are you sure it was side-by-side?

does anyone have blueprints or diagrams. i know a welder and just need a diagram.


I rode Ken Fuch’s tandem unicycle many moons ago with several different people. It is very awkward at first to get used to but after awhile you get used to it. Falling off safely is the hard part, with turning coming in second.

What works the best is for the person sitting in the back to ‘control’ the unicycle while the person up front just lightly pedals. The person that weighs more should sit in the back. We were both facing forward (the same direction) and not looking at each other. The problem with his uni I remember is that it had a bar from seat to seat (like a mens bike vs. a womens bike) so that if you fall forward, the guy in the back could easily hurt himself (if you know what I mean) by landing on the bar. And vice versa if you fell off backwards. Definetly some scary falls trying to learn how to ride it but so cool once you figure it out. The best I did was probably 20-30 meters? I was usually in the front since I was the lightest and it was so wierd at first cause it feels like you’re going to fall off.

You could ride it with only one person as well! My friend actually made a frame many years ago and just hasn’t gotten around to putting the wheel, chain, seats on. I’ve been trying to convince him for awhile but he just never gets around to it. Maybe I’ll buy it from him and do it myself.

I think the side by side tandem would be more difficult (to ride and build) but fun to try?!

I’ve been told it is, but then only 1 person should be “riding” and the other “not”.

What’s wrong with sitting opposit to me?
Unfortunely I’ve been also told the tandem-unicycle was shipped to the US… but they are available on request.

If both riders have both have a side-ride caliber of skills…
…then still I wonder how you are gonne deal with a weigth difference between riders?