# Convert a bike into a unicycle

Hi everybody,

Have an idea to build a faster geared unicycle with a bike. But it is very
difficult for me to do the welding work at home.
Just found a potential 16-inch bike in internet to convert into a geared uncycle with very little modification (maybe no cutting or weld needed).

See if it will work?

Just remove the first half. As the seat is connected with the rear wheel with a movable joint for suspension, just remove the spring and fold the seat forward. Find something longer to replace the spring to fix the seat in forward position. The only problem is the gear on the rear wheel. Have to replace it with with a fixed one or do a welding to let the wheel turn forward or backward. (This part is what I am not very sure).

Without the fixed gear on the rear wheel, can I still ride forward (no idling or riding backward)? I donâ€™t know.

This drawing shows what I want to do with it.
The gear ratio is about 3 times. It will be similar to a 48-inch with the 16-inch wheel.

I am no engineer to tell you if itâ€™s possible or not, Iâ€™m 14.

But I do know that having a geared 16 inch wheel will be of no use other than for show. If you want a useful geared unicycle, make it with a 24, 26, 29, or 36 inch wheel. Or get a Schlumpf. If you donâ€™t know what that is, type it in on unicycle.com, and youâ€™ll see. Itâ€™s a geared hub.

A geared hub can only has the gear ratio of 1.5 max as I know. So, even a 36-inch wheel will only equal to 54-inch performance. 29er will give 43.5.

Therefore, I think 16x3=48 is not too bad.

Of course, the center of mass is higher like a short giraffe. The center of the pedals is now around 36-inch from the ground compared to 18-inch of a 36er. I donâ€™t know a 18-inch higher height will make a big difference.

If he gears 3:1 like he says, he will have an (effective) 48" wheel. Which is approaching a Schlumpf (max 54" effective, with 36" physical wheel).

Drivetrain-wise, he could make a Schlumpf work on there pretty easily, but working the shift buttons would take some design and fab work. I havenâ€™t heard of anyone making a remote shifter for his Schlumpf yet. . .

Heâ€™s frame-limited to a 16" wheel (it looks like), so heâ€™s going to need to gear it, most easily would be to swap out hubs, put bearing cups on the ends, and accomplish gearing with sprockets. Losing the ability to reverse seems incredibly limiting to me, making the bike drivetrain rather unattractive.

As long as you donâ€™t let the height get to you, the higher pedals make it a bit easier. Seems to be a much longer period through which you cna swing around the top. Makes things happen slower, effectively, making the riding a bit easier. For me anyway. YMMV.

I donâ€™t understand what this means very much. I donâ€™t think I can shift the gear. And just keep the original 3:1 gear & chain. Just modify the rear gear to let the wheel go reverse.

By the way, anyone try a geared giraffe other than 1:1 ratio? Is it possible to ride?

yeah there have been geared giraffes. but 3:1 is really highâ€¦I have never rode a geared uni but i think it gets much harder the larger the ratio. i think i read somewhere someone tried a 1:1.96 or whatever and its reallllly finickyâ€¦

maybe if you just kept at it you could do it? but it definitely wouldnt be easy to ride at firstâ€¦

Okay, Iâ€™ll just say it. If you think that youâ€™re going to gear that thing 1:3 and just cruise around town, that will not be the case. A 16" wheel will not handle road imperfections well at all, not like a 29" or 36" wheels that will roll right over most anything.

Also, you wouldnâ€™t be able to ride that thing if it freewheels. Take it from me; Iâ€™ve put about a month of practice into riding a coasting unicycle, and it is very, very difficult, and I can get maybe 100 yards tops. If you arenâ€™t willing to put a lot of money into this or do some heavy modifications, then you arenâ€™t going to get anything practical out of it.

good point. Didnâ€™t think of the 16-inch on the road. This 16-inch geared unicycle is not very practical.

I took of these bikes:

I cut the seat tube out, and the swing arm, had a friend weld it, and it ended up as a mini-giraffe-unicycle.

I replaced the freewheel with a screw on fixed wheel sprocket, which is held on with epoxy.

Yeah, itâ€™s by no means practical, but itâ€™s cool.

Iâ€™d go along with the general consensus that it wonâ€™t work, and here are a few reasons (some have already been mentioned);

A 16" wheel geared up to a 48" effective diameter will not ride like a 48" wheel. It is just too small and skittish for anything other than the smoothest of surfaces.

The hub appears to be internally geared Sturmey Archer type. Welding the cog to the hub will give you a fixed 1:1. If you strip it down you may be able to find which bits to weld to which bits, but really, youâ€™ll be lucky to get it back together again.

Most of the gearing ratio is based on the front chain ring being much larger than the rear one. On that basis, youâ€™re better off with a normal hub and experimenting with different size fixie sprockets.

If you really want to experiment with geared giraffes, youâ€™re better off starting out with a regular 20" and either playing with the two sprocket sizes and/or by trying to fit in a 24" wheel in to the frame.

There have been a lot of geared giraffes made already. Have a search around the forum and youâ€™ll see a lot of examples.

STM

I recently built a similar unicycle from a bike but i canâ€™t ride it. Gear ratio about 1:3 with freewheeling hub. Prehaps you can build a better one which is actually rideable.

Thar she be! A better seat and a little less play in the pedaling action would be great.

The Troxelator

Cool!!! Whatâ€™re the riding experience of the â€śmini-giraffe-unicycleâ€ť & â€śThe Troxelatorâ€ť ?

Any photo to show how to do this modification?

Any photos?