I have commissioned Dave at DM Engineering to build my hand driven unicycle.
Will post photos of it when I actually get it.
But I need advice before he puts it in to material affect.
What size tyre should I untilise; 24" or 20" what would suit the hand crank method?
Any advice on this greatly appreciated as he is about to materialise the design!
Thanks.
JJ
I would suggest a 24" just so you can get going somewhat quickly. A 20" would seem a bit small. Ad if you plan on going enywhere, get the 24" so your arms don’t poop out.
I am going to go for a 20" with my seated hand-driven uni, and gear it up to whatever feels good. Good luck! I’ll build mine one of these days.
Andrew
Start un-technical waffle:
If you allow the legs on the frame (or would they be forks? dropouts?al enough, you could allow it to accomodate any size wheel up to say, a 29". that way you could experiment with the wheel size & see what suits, without having to change the frame.
End un-technical waffle.
There’s a suggestion in there somewhere…
A friend of mine rides his giraffe by standing on pegs that are attached to the axle, and pedaling with one hand while he holds the frame above the pedals with his other hand. He can go very far like that if he doesnt have to go up too many hills.
His giraffe has a 20" wheel. I’ll try to ask him if he thinks a bigger wheel would be an improvement.
Your custom uni sounds like a very cool idea and i look forward to pictures.
Since you have a chain, you can gear it any way you want. So unless you intend to only cover lots of miles, I’d start with a 20" wheel. It will be lighter, which will make it easier to work with during the learning stages.
If you follow the non-technical advice posted above, ask DM to leave room in the fork for a larger wheel. Then you have the option of trading up in the future.
With a 20" wheel you also have tons more choices of rim and tire to work with.
i am doing a 16"
Thanks for all the advise that you have given.
So I am going for a 20" with a frame large enough for a 26".
Have no plans for gearing yet, but once I am up and riding then perhaps I will.
´The friend who rides a giraffe with one arm not two has inspired me that this will actually be rideable, was wondering if I would manage’.
Concerned I think that I will manage the balance issues with out my flailing arms! Arghh.
JJ
Re: New Unicycle Design commissioned !
On Tue, 11 Jan 2005 02:03:56 -0600, “fontiminal” wrote:
>What size tyre should I untilise; 24" or 20" what would suit the hand
>crank method?
I would say 20". The smaller the tyre, the lower the forces that you
will have to muster on the ‘pedals’. And that’s good because obviously
your arms are much weaker than your legs.
“Pedals” is an inappropriate word, BTW, because it refers to feet. But
“manuals” doesn’t ring right either.
It’s impossible to get old when you ride a unicycle - John (what’s in a name) Childs
Re: Re: New Unicycle Design commissioned !
handles? 
Re: Re: Re: New Unicycle Design commissioned !
Well, handles to me sounds like you mainly grip them, not ‘operate’ them. Maybe we should get used to manuals. I like it after tasting the word for a while. After all, a large organ (musical instrument) also has pedals and (at least one, but often several) manuals.
Umm, strictly speaking I think that all of the foot-operated levers on an organ are collectively called “the pedal”, and similarly all the hand-operated levers on one row are collectively called “a (one) manual”. So, singular, not plural. Oh well.
Klaas Bil
Klaas are you forgetting that this thing has a chain and can easily be geared to make a 20" wheel seem like a 29" and vice versa?
There you have a point Andrew. OK I guess I should have said that the relative weakness of the arms is something to keep in mind when choosing a gear ratio (along with the wheel size of course).
Klaas Bil
Re: Re: Re: Re: New Unicycle Design commissioned !
Klaas, are you forgetting we’re talking about a unicycle? 
Re: New Unicycle Design commissioned !
“Klaas Bil” <Klaas.Bil@NoEmail.Message.Poster.at.Unicyclist.com> wrote in
message news:Klaas.Bil.1iqrh8@NoEmail.Message.Poster.at.Unicyclist.com…
>
> mikepenton wrote:
>> *handles? 
*
> Well, handles to me sounds like you mainly grip them, not ‘operate’
> them. Maybe we should get used to manuals. I like it after tasting the
> word for a while. After all, a large organ (musical instrument) also has
> pedals and (at least one, but often several) manuals.
>
I dunno: years ago cars had starting “handles” which you certainly had
to turn by hand, so a precedent has been decades ago. Also barrel
organs, which had hand cranked handles. Modern pipe/ electronic organs
are rather more like banks of switches as the hands/feet hardly do much
work.
Nao
Re: Re: New Unicycle Design commissioned !
Though I don’t think either of us is old enough to remember first-hand, these were also called cranks.
Since it is possible to buy “pedals” that are made for hand-cranking, I would presume there is already a name for them. When I hand-crank my giraffe I just use pedals, though I switched from spikey rat-traps back to the original block ones for this purpose.
Since the rest of the system is all built from a drivetrain designed for foot operation, I don’t have a problem with calling them hand-pedals or something similar.
Gearing:
I’d start low. It’s a lot of work learning to hand-crank a giraffe, and a higher ratio will only make it harder. I’d start with either 1:1 or something not much higher. Don’t gear your wheel size past 24" at first.
All of my giraffe hand-cranking is done with one hand on the pedal and the other holding either the frame or the seat. It is possible also to work the pedals with both hands, and I’ve seen people do this very well. I’ve never seen anyone bash themselves in the face while doing it, but this has inhibited me from learning the both-handed cranking. If you’re sitting on a seat it will help hold the frame in place.
Re: Re: Re: New Unicycle Design commissioned !
Had not even occured to me till an earlier post that I could use one hand on the hadal (ped for feet, had for hands? <laughs>) and the other on some sort of handle in front of the seat. So I´ve asked Dave at DM to include a handle, that really has thrown him!
Am concerned about being bashed in the face by the drive system, will have that totally enclosed since I could put my arm through it if I took a UPD. Perhaps a fulled enclosed helmet might be required for learning! <shakes head> Umm.
Have decided on a 20" and no gearing, I think that will be easier to learn, larger wheels require greater torque to turn, my arms would be falling off if I go big.
JJ
p.s. Am I going mad actually having this thing built?
I have seen a recumbant bike that you crank with your arms on the bike path near my home. The cranks work like a uni with both cranks faceing the ground. I think thats called kangaroo when used on a uni.
The rider sits with the cranks in frunt of him at chest hight and sort of rows along with both arms.
Cheers Dave
Re: New Unicycle Design commissioned !
Ottawa Dave wrote:
> I have seen a recumbant bike that you crank with your arms on the bike
> path near my home. The cranks work like a uni with both cranks faceing
> the ground. I think thats called kangaroo when used on a uni.
Are you sure it wasn’t a trike? Hand-cranked cycles are usually made
for people who don’t have use of their legs, so the rider needs to be
able to stop without having to put his feet down. So they’re usually
strikes. I know of one company that makes hand-cranked bikes (with
outriggers), but I’ve never actually seen one:
<URL:http://www.mobilityeng.com/>
I’ve seen quite a few hand-cranked strikes at BHPC events [1].
> The rider sits with the cranks in frunt of him at chest hight and sort
> of rows along with both arms.
Or maybe a rowingbike: <URL:http://www.rowingbike.com/main.php>
[1] British Human Power Club: <URL:http://www.bhpc.org.uk/>
–
Danny Colyer (the UK company has been laughed out of my reply address)
<URL:http://www.speedy5.freeserve.co.uk/danny/>
“He who dares not offend cannot be honest.” - Thomas Paine
Re: New Unicycle Design commissioned !
I wrote:
> So they’re usually strikes.
<snip>
> I’ve seen quite a few hand-cranked strikes at BHPC events
Well, actually I didn’t. I wrote “trikes”. Damn this spellchecker - I
thought I’d clicked “Add”, not “Replace”.
–
Danny Colyer (the UK company has been laughed out of my reply address)
<URL:http://www.speedy5.freeserve.co.uk/danny/>
“He who dares not offend cannot be honest.” - Thomas Paine