I’m sorry if this doesn’t make sense or wouldn’t work but why hasn’t anyone made a geared giraffe? I thought you could use the same principles for the gears as with a bike.
For a start you could have 2 or 3 gears on the top chainring that could change with the use of a front derailleur from a bike. With a little practice couldn’t you then change gears while riding along by using a lever below the seat?
Another idea that probably doesn’t work but that I find exciting is changing the hub so that it has some sort of a cluster without a freewheel mechanism. Then you could attach gears that shift the same way as on a bike. If this thing worked anyone who was brave enough could ride really quickly on a giraffe. You would also have the option of a ‘granny gear’ for climbing steep hills.
Wouldn’t it be great to see someone riding one of these things at 40km/h!
Please bring me back down to Earth if this is impossible,
Andrew Carter
Derailleur gears as used on most modern bicycles rely on there being some slack in the chain, which is taken up by a spring loaded derailleur arm. This takes up the slack on one side of the rear cog. This means that you can only change gear when pedalling forwards.
Take the freewheel out of the mechanism (as you would need to on a giraffe) and you find that if you apply back pressure to slow down, the derailleur mechanism will get tangled. Messy.
And if you use hub gears, you end up with the same ‘transmission lash’ problem that Mr. Harper has been working to eliminate on the uni.5 hub.
Also, many good quality giraffes have one chain on each side. Imagine the adjustments required for a geared uni with two chains!
Nice idea though, and if you only wanted to ride fast on the flat (like drag racing) you could do it. Send us the photos, and we’ll send the grapes to your ward ;0)
I had a giraffe that was geared up 2:3 (the top ring was bigger). It was not shiftable but it gave me an effective wheel size of 30" on my 20" wheel. I rode it around town for transportation for a couple of weeks before I decide I like being closer to the ground and went back to my “regular” commuter cycle.
I know that many others have changed the gear ratio on a giraffe. I suspect that nearly all who have have considered ways to accomplish on-the-fly shifting. Apparently it is still too complicated, expensive, or both since such a device has never, to my knowledge, been created.
My thought (anyone want to poke holes in this idea feel free) was to have a double drive (chain on both sides) with a derrailluer (sp?) on both sides. When one goes slack the other is taut. Only problem is that, although you can now shift you end up with mismatched gear ratios for forward/reverse.
I thought I had read about a giraffe equipped with a Sturmey-Archer hub. With the giraffe, the only modification required is to make it reversible because the giraffe wheel is already cog, or sprocket, driven. This giraffe (and this also may only be part of my belief system, not fact) I BELIEVE was shiftable on the fly.
I also BELIEVE that most modern giraffes are geared up slightly (7:6 or so) in order to insure uniform tire wear.
Wear on a unicycle tire is most commonly on the two positions corresponding to the cranks being horizontal. This is usually where they are when riders twist or turn sharply. The tire tends to wear more in these spots. Rotating the tire every so often helps to redistribute the wear pattern. If the tire is in a random position when the cranks are horizontal it will wear evenly. No gear ratio can produce an entirely random pattern but good coverage can be achieved if the ratio is close to but not equal to one. Think about what is happening if you turn the cranks around six times and the wheel goes around seven times. For each left forward crank position there are seven different tire positions rather than just one. Same for right crank forward.
That fiendish device that Unibiker rides is effectively a geared giraffe. Unibiker: does it still have a freewheel? My guess is it won’t idle or reverse and that riding it is more like doing a wheelie on a bicycle than riding a conventional unicycle. Any comments?
Another idea for a changeable geared giraffe. Some fundamentalist bicyclists ride a fixed wheel (no freewheel) and have a hub with a sprocket on each side - so they can slip the wheel out and put it in either way, giving a choice of two possible gears. With a giraffe with a single chain, something similar could be done, although you’d need a chain tensioner.
>With a giraffe with
>a single chain, something similar could be done, although you’d need a
>chain tensioner.
A spring-loaded chain tensioner like on a bike with a derailleur would
be bad on a giraffe. However, I guess that you need a mechanism to
tension the chain on any giraffe to compensate for slack resulting
from chain strain. A system like that found on many older bikes where
you turn a nut (one on each side) to pull the wheel slightly backward
would work, and it would be OK on your dual-sprocketed giraffe as
well.
Klaas Bil
There are as many as 78 scenes in an average X-files episode.
Don’t know why it would be so terrifying, unless it’s a big change of ratio or if you have to do something like freewheel to get the gear to change. Then I can see it!
I’ve read a lot about using Sturmey Archer hubs on unicycles, but this is the first time I remember hearing of someone actually seeing one. Next would be some first-hand info from someone who rode one.
For info on how to build your own “geared-up” giraffe, you can read my first-ever article in the USA Newsletter, October 1980 issue. Send away for a full back-issue set and it’ll be in there. In that article I describe how to take apart your Schwinn Giraffe and the choices (at that time) of top chainring size and how they performed.
Changing the top ring usually requires you add or remove chain links. If you can manage it, changing the size of the bottom ring (sprocket) probably doesn’t.
When Walter Nilsson rode across the US in 1933 for the Ripley’s $10,000 prize, he had a giraffe with a different sized sprocket on each side of the wheel. It also had very long dropouts in the bottom of the fork, eliminating the need to mess with chain links. Turning the wheel around would switch him from mountains to level ground, I suspect.
Not much in the way of new developments in the technology of giraffes these days…
Yes, I’m still using a freewheel hub (safely modified with an old style axle; the only ‘quick release’ item that’s left is the rider ). I think it would feel more like a conventional unicycle with a locked hub, but I’ve never tried it. However, then it wouldn’t be shiftable, wouldn’t be as challenging to ride, and wouldn’t get used much.
No idling. No reverse. And it doesn’t work too well on the MUni trails. But brake gliding is a blast, and I don’t have to worry about transitioning back to the pedals. It’s also easier on the bad knee, since there is no force applied during the back half of the crank revolution, when the knee is more collapsed.
The Sturmey Archer gear (Three speed, fixed wheel, ASC model) disengages while you shift. I seem to recall that on the giraffe at BJC this equated to around 1/4 to 1/2 a turn of slack in the pedals until it kicked in again. A bit scarey.
My giraffe has two gears making it about a 20" or a 26" but you can only change it with a spanner. It takes about 30 seconds to do (Not including half a dozen atempts at trying to remount it)
I’ve got my new computer set-up so I can take some digital pics now. Unfortunately most of my unis are still at my old house. I’ll try and take some at the weekend.
Its not especially impressive; it basically has a long set of drop-outs to take up the chain slack and chain tensioner similar to a motorbike to make moving the axle easier.
Everything is impressive for people who like to tinker. If someone sees that you have done this in some clever, elegant, simple way it gives them the motivation to experiment also. I’m not the only one here that would look forward to seeing photos of a project like this. I just wish Michael Grant had a digital camera when he was doing his giraffe projects.
I know this sounds like a stupid idea, and for all intents and purposes I think it is, but what if you tried making a geared giraffe with two freewheels. My idea would work by using one set for forward and one set for reverse. When moving forward only one would be engaged, while the other was freewheeling. When you reverse, the other set would engage and the first set would freewheel. Of course this would mean that you would need two sets of derailers, and chains and so forth. You would also need to shift both at the same time. I believe this would eliminate the “mess” associated with trying to back pedal with a geared locked hub.
So tell me, on a scale from 1to 10 with one being the stupidest idea you ever heard (on the order of the jump to conclusions mat) and ten being an absolute stroke of genius, where does this idea fall.
). I think it would feel more like a conventional unicycle with a locked hub, but I’ve never tried it. However, then it wouldn’t be shiftable, wouldn’t be as challenging to ride, and wouldn’t get used much.