Geared Unicycle Talk

I gave a talk in August on my favorite unicycling theme: geared unicycles. I brought my three geared unicycles (Schlumpf 29", Penguin Giraffe, and Red Menace).

The talk was at Ignite Seattle which is an event that has 15-16 people give talks in one evening. Each speaker gets twenty slides which auto-advance every fifteen seconds. The format forces you to get to the point very quickly. It was challenging to describe these three unicycles in so short a time, especially since my audience knew nothing about unicycling. I had to explain why gears were needed, why they were tricky and how the problems were solved.

If you ever have a chance to attend an Ignite event, do. They are great fun. Speaking at them is also fun.

I’ve got more details and a link to the youtube video of the talk here:

I’ve followed your blog for a while, I like reading about your day job too :smiley: If I tell you I love unicycles enough will you send me a beta steambox? :smiley:

On topic… Geared unicycling has been an interest for me since before I started riding (As to me this is the only hurdle stopping uni’s being as fast as bikes, besides rider skill/bravery), so looking forward to the talk :smiley:

Thanks Bruce!

Not only a great talk, but I’m in it at 2:21!

Other unicyclists


I forgot that some other unicyclists showed up in the slides – I hope nobody minds. There are two potentially recognizable people from the Ride The Lobster criterium in slide 9 (are you the one in the background?), and a unicyclist’s bloody wounds in slide 18.

Well done!

btw, last week at work I was battling a difference in 32-bit and 64-bit floating point precision issues. The best info I googled was on your blog. Kind of funny telling my coworker friends my solution came from the blog of another geared unicycle rider and grease customer. Quite a coincidence! Thanks for that info!

Great talk; I enjoyed it.

Are there any jack-shaft unicycle available for sale? How do they compare with the Schlumpf geared systems?


It’s interesting to know a little more about geared unicycles. Thanks.

One road to arithmetic

Come for the geared unicycles, stay for the binary floating-point arithmetic lessons.

Pete Perron is the only person I know who has made jack-shaft based unicycles, and he only made two. I bought one, somebody else bought the other. I think Pete still hopes that somebody will take his design and make more of it.

The main advantage of the Schlumpf unicycles is the ability to shift on the fly. The main advantage of the jack-shaft based unicycles is the ability to select any gear ratio you want.

When I said that it took ten minutes to change gears on the jack-shaft unicycle the audience laughed. It hadn’t occurred to me that that was funny. It’s too bad that the video didn’t capture audience reactions.

I thought he made three. Purple Phase, Green something or other, and Red Menace.

Florian green is people!

Wasn’t Florian Green a Schlumpf unicycle?

Besides, if I didn’t ride it then it didn’t exist.

I thought everybody had one in their garage…

Here is mine:

Never seen that before, what are the specs?

Hey Bruce!

We were just talking about you at Duthie Hill this weekend. Your name usually comes up when anyone around here starts talking about other riders in the area, plus the Solstice Parade of course. :slight_smile:

Let me know if you give more talks like this, I’d like to see it in person (and heckle).

I thought the Huni-rex unis were jackshaft driven. :thinking:

Huni-rex does have the pedals offset from the wheel axle (below the axle, weird) but it isn’t a jack-shaft in the same sense of Purple Phase/Red Menace. There’s a single chain running from the pedals to the wheel axle. I’m not sure whether that counts as a jackshaft or not, but it certainly feels like a quite different design from Purple Phase/Red Menace.

I ignore Huni-rex purely because I don’t own one.

I’m blurry and in the foreground. The Blue Nimbus with the yellow fender.


Thank you for looking fast. That’s all I needed for that slide.

Nice presentation Bruce. You have “brand equity” with me for your “STP” chronicle, of course, but I wouldn’t shine you on. Really informative and it never felt rushed or bogged down, You brought your “A” game.

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Pete Perron made three V frame unicycles. Two of them, Red Menace and Purple Phase, are jack shaft designs. Florian Green is a Schlumpf. It’s one of the early, pre KH, Schlumpf hubs. #0079. I’ve got 9,000 km on it and it’s still going strong. Here’s a pic from a few years ago. I’ve since replaced the bent handlebar stem.