Another future unicycle project...

At the moment I’m saving for a GP trials uni and the materials and parts for a seated hand-driven unicycle, but there’s a new addition to the list.

I want to have a two-wheeler made, possibly to be able to fit different sizes of wheels. My main goal is to have it built with a bigger wheel on the top than the bottom or vice-versa (which do you think would be more fun?). I might put a 24" on top and a 16" on the bottom or a 20" (easier to find with hub and cranks installed) on top and 24" on the bottom.

Could someone please tell me where I could find a detailed photo of either a two or three wheeler uniccyle? I’m mainly interested in the part of the frame at the top wheel. Also, could someone please tell me how the little frame extension things from unicycle.com can hold the bottom half of the uni still? I thought that if they just attach to the top of the bearing holders, they’d be really weak.

These little projects are fun. I’ll finish them all one day!

Thanks a lot,
Andrew

Re: Another future unicycle project…

has this ever been done?
isn’t this another innovative way of gearing up a raffie?
with a 20 at the top and a 24 at the bottom i can imagine u must be able to get some serious speed going
why not a 20/24/26-9 three wheeler?

Re: Re: Another future unicycle project…

I was about to say “the other way round, surely?”, based on memories of playing with lego gears (aaah… :)) but then the thought occured, will different sized wheels actually make a difference?

I have a feeling it’s only the size of the top wheel that is important, the lower wheel will transfer the motion at the same rate, it’ll just rotate slower if it’s a bigger wheel.

Phil

Re: Re: Re: Another future unicycle project…

yeah, u r quite right
so my three stack would have to be 29/24/20?
i’m sure we can count on our scientifically minded friends to confirm or deny your closing remark

I thought of the possibility of gearing a giraffe this way but came to the conclusion that it wouldn’t make a difference. Please correct me if I’m wrong…it would actually be good news. Having different sized wheels would change the riding experience. I’d imagine that a 16" on top and 26" or so on the bottom would be a really smooth ride but less responsive…the other way around would just be weird (which may well be the setup I’ll choose).

Andrew

Re: Re: Re: Re: Another future unicycle project…

This would also just depend on the size of the top wheel… the speed of the edges of the wheels will still be the same.

The only way to gear it up would be to have two wheels on one axle… if the upper wheel made contact with a 12" wheel on the same axle as a coker wheel that touched the ground, it would be a serious speed demon…

I suppose this is kindof how giraffes work, with the lower cog being smaller than the actual wheel.

Phil

It would go at the speed of the top wheel. If the top wheel moves 1 metre, it forces the area of contact with the lower wheel to move 1 metre (but in the opposite direction), and this is correspondingly transferred to the ground.

Could still be an interesting way of gearing it though. Use one of the huge wheels with solid tyres on the top, and a smaller wheel (or two) with pneumatic tyre on the bottom. Should still give you the comfort of the pneumatic tyre, I reckon it would be a bit bizarre to ride though :slight_smile:

Edit:

Isn’t the traditional way of getting onto a multi-wheeled unicycle to “climb” up the wheels? Wouldn’t having a larger top wheel than bottom wheel make this ridiculously hard to do?

I would’ve thought that a two-wheeler would be low enough to just go straight to the lower pedal and step up.

Andrew

Yes, Andrew, they are low enough to step up and mount, like a 5’ giraffe. The side mount works best for 2-wheelers. I’ve ridden a 2-wheeler with 20" wheels and one with 16" wheels.

They are a real fun challenge as you have to un-learn all your ingrained uni riding tendencies. Pretty you have to learn to ride again when you take on the 2-wheeler challenge!

I’ve been thinking of building a two wheeler. Which wheel size is better, 20" or 16"?

If you end up building one, it’ll probably be before me so could you please post updates about your building and riding progress? I’ve got a trials uni to buy and a seated hand-driven uni to have made before a 2 wheeler.

Thanks,
Andrew

Re: Another future unicycle project…

On Mon, 30 Jun 2003 21:38:23 -0500, DasDingus
<DasDingus.pv9xn@timelimit.unicyclist.com> wrote:

>I’ve been thinking of building a two wheeler. Which wheel size is
>better, 20" or 16"?

I’ve never ridden one, but the one I’ve seen ridden had at least 20"
wheels, probably 24". It might be that a 16" would add a bit too much
nervousness to the equation.

Klaas Bil - Newsgroup Addict

You have the right to remain silent. Anything you say may end up in someone’s sig line and used against you.

Re: Another future unicycle project…

>> I’ve ridden a 2-wheeler with 20" wheels and one with 16" wheels.

DasDingus <DasDingus.pv9xn@timelimit.unicyclist.com> wrote:

>I’ve been thinking of building a two wheeler. Which wheel size is
>better, 20" or 16"?

I’d recommend the 16". It is easier to mount, ride, wheel walk, and
transport in a passenger vehicle.

Sincerely,

Ken Fuchs <kfuchs@winternet.com>

Wow, wheel walking a two-wheeler! Do you wheel walk forwards on th bottom tyre or backwards on the top?

Has anyone got any photos of their two-wheelers?

Now I’ve got a decision to make…
Should I make a two wheeler with 24" on top and 12" on the bottom, or 12" or smaller top and bottom?

The second option is looking very tempting. Would there be anything available that’s smaller than a 12" wheel? 8" maybe?

What is the best type of tyre to use? If knobby is bad, that may be a problem because it seems like most tiny tyres are knobby.

Thanks,
Andrew

Re: Another future unicycle project…

andrew_carter <andrew_carter.px9go@timelimit.unicyclist.com> wrote:

>Wow, wheel walking a two-wheeler! Do you wheel walk forwards on th
>bottom tyre or backwards on the top?

Either direction works fine:

To move forward, one would propel the top wheel backward. To move
backward, one would propel the top wheel forward. Wheel walking
(cycle moving) forward is easier than wheel walking backward.

>Now I’ve got a decision to make…
>SHOULD I MAKE A TWO WHEELER WITH 24" ON TOP AND 12" ON THE BOTTOM, OR
>12" OR SMALLER TOP AND BOTTOM?

>The second option is looking very tempting. Would there be anything
>available that’s smaller than a 12" wheel? 8" maybe?

The smallest I’ve ridden is a 16" and that seems to be the right size
for doing most skills. A 12" sounds fine, although one would be
spinning the pedals a lot to get anywhere, but I’m sure it would be fun
and closer to the ground (axle at 18" high same as a Coker). The 8"
might be more of a novelty cycle (axle at only 12" high).

>What is the best type of tyre to use? If knobby is bad, that may be a
>problem because it seems like most tiny tyres are knobby.

A smooth tire with a square cross section. Wider is better, so the
tires don’t loose contact. Smaller diameter tires are better, since
they are wider relative to wheel diameter, thus rarely loose contact
since the frame can’t flex that much.

Loosing tire contact is a problem with flat steel frames with 24" or
larger tires. They flex a bit too much. A flat steel frame should work
fine with 16" or smaller wheels, assuming the wheels are properly
aligned. A properly aligned tube frame should work fine with almost any
wheel size.

Sincerely,

Ken Fuchs <kfuchs@winternet.com>

Thanks a lot Ken. I think whatever size I choose the aim is for it to be a novelty uni. If I really feel like doing freestyle tricks and stuff like that on it, I’ll have to make another but I doubt I’ll ever get that good on it.

Thanks,
Andrew

Two-wheeler update…

No I haven’t given up…I’m just searching for parts. Gary is hunting down a hub and crankset for me now so it’ll hopefully be up and running pretty soon. I’ve got a couple of 12" wheels (bike wheels) to use but the problem is they have 16 spokes and I have to put a unicycle hub into one! Would I be better off lacing one up with a 28 hole hub or a 36 hole hub? I guess given the size I’m using and what I’ll be doing on it it doesn’t really matter but still…

Andrew

Scratch that…I’ve got a 20 hole rim to fit with a 28 or 36 hole hub. It’s single walled and there’s plenty of room to drill more holes. I could turn it into a 40 hole rim easily without compromising strength. I don’t know if that will help though. I’m having trouble figuring out how to fit them together.

Maybe I could cut the flanges of the hub down so that there are no holes, then weld a bit onto that with 20 holes drilled into it. I don’t have any of the tools to do that though.

This is a bit tricky.

Andrew