geared up mini-giraffe speed machine?



U

unisteve

Guest
All this talk about geared unicycles had put it into my head that I need
a super fast unicycle. I want something that can keep up to those
people who ride bikes. I'm tired of having to ask them to slow down
because I can't keep up, but I'm not willing to switch over to the
other team, if you know what I mean.

I don't like the idea of Cokers because the huge wheel limits some of
the take-it-with-you-everywhere-a-bility that I've come to love in my
unicycles.

So, I've got a proposal for a wicked sick geared mini-giraffe.

Think of it:
-a 24x3 slick cruiser bike tire for pavement pwnage
-geared up about 1:2 (or 2:1, whichever one makes the wheel a 48"
equivalent)

The idea would be to have the pedals just above the wheel, to keep the
size down. The only reason I'm thinking giraffe is because these
unicycles with geared hubs are not that cheap. I think I could do a
mini-giraffe for cheaper that would give me the same kind of speed.

Does this make any sense?

I've attached a quick little Paint diagram.

(I believe this kind of thing has been done before, but I haven't seen
too many of them... That's why I'm asking for feedback.)


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unisteve

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la vie est belle...

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you would want twice as many teeth on the top sprocket than the bottom.

i have a design in my head for making a geared uni with chains and
everything, but it sits at the same hight as a normal on, ill try to do
a diagram of it one of these days


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unijesse

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Abram Clark made just what you're talking about...

'Abram's blog - der uber giraffe'
(http://abram.atypedigital.com/2005/photos/projects/giraffe/)

'Pictures in Harper's gallery' (http://tinyurl.com/lu5bp)

I've got an old 6' Savage that I'm hoping to do the same thing with...
it looks wicked cool!


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maestro8

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Been done before.

It isn't much more compact than a Coker when you are extending the
crankset over the wheel. In fact, I think it will take up even more
space than a Coker if you are trying to transport it. The alternative
is to have the cranks just slightly above the axle (like Pete Perons
Purple Phaze)

Also less stable as your centre of gravity is higher, and hence slower
than a internally hub geared unicycle. You can gear it up as high as
you like, but the higher the gear, the more unstable it will be. I
don't think you'd go as fast as on a standard direct drive Coker simply
because you wouldn't have the confidence to, no matter how high you
gear it up.

Also drivetrain issues- if the chain slips it can result in a nasty
UPD. But same potential problem with any sort of geared hub. If you
go for a geared system- make sure it is robust.

Ken


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GizmoDuck

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The SINZ Unitour- coming soon......
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A 2:1 ratio on a 24" wheel will still leave you struggling to keep up
with the bikes. On flat ground. Not to mention the mess to be cleaned
up each time you UPD at high speed. Falling from a giraffe at 15+ mph
is not pretty. Been there, on an almost-2:1 Schwinn Giraffe. Sure,
you're going real fast, but the smaller your wheel the less well it
rolls over bumps. And being higher up, your angle of landing is just
not good.

By the time you build a giraffe with gearing the way you want, you'll
find it's about the same height, or more, than a Coker. It will still
fit in a smaller space, but the Coker (or Schlumph) will have the
advantage. Yours may be cheaper to make though, if you have a giraffe
to start with.


--
johnfoss

John Foss
"jfoss" at "unicycling.com" -- www.unicycling.com
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"The worst thing you can do on a unicycle when you land is stop dead."
-- Kris Holm, world's expert on high-consequence unicycling
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I believe George Barnes (GB4 engineering) made one with a 26" wheel but
the drive on each side was seperate so the axle didn't need to be above
the top of the wheel. This is much more complicated to do. there are
videos on here somewhere of him going very fast down the side of a
road, try searching for them and photos of how he did it.


--
kington99

Dave

- what a thoroughly post-modern subversion of the cycling genre -
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maestro8 wrote:
> Abram Clark made just what you're talking about...
>
> 'Abram's blog - der uber giraffe'
> (http://abram.atypedigital.com/2005/photos/projects/giraffe/)
>
> 'Pictures in Harper's gallery' (http://tinyurl.com/lu5bp)
>
> I've got an old 6' Savage that I'm hoping to do the same thing with...
> it looks wicked cool!




The videos suggest this is a very practical and cost effective beast.
I wonder whether these were the first few rides on the thing? I note
the cranks are just about as low down as feasible whilst still clearing
the tyre. I think I want one.


Nao


--
Naomi

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not lack for Gods. The collection plates are just much bigger, and
they get to pay in advance. (Naomi 2005)

Every breath you take, every move you make... contributes towards
global warming.
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Someone I know once made a giraffe geared to 1:8 but I don't think he
could ride it...anyhoo, you should try it!


--
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