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I find bicycle chain a little clumsy. Here is an attempt to get rid of them.
Move the seat backward, right on top rear wheel. Get rid of crankwheel and hence the chain. Pedals now are attached directly to rear axle. Rider now pedals the rear wheel directly.
Lesser things to go wrong and mentain.
Now there will be more weight on rear wheel. So it will have to be made stronger.
chainless bicycles
http://en.wikipedia...i/Chainless_bicycle
[xaviergisz, Jan 25 2011]
Super Minimal
http://www.thecycle...super_minimal_1.jpg
Designed by jruiter + studio, the Super-Minimal city bike has an original frame featuring front suspension, disc brake and a rear planetary hub directly connected to pedals. [baconbrain, Jan 28 2011]
Bicymple
http://www.bicymple.com/
A chainless bicycle [theircompetitor, Oct 13 2012]
Sussex bikes
http://www.treehugg...ions-by-sussex.html
Chainless- shaft drive. [8th of 7, Oct 13 2012]
[link]
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If the front wheel lifts slightly you'd fall backwards. |
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Presumably this removes the options for gears too? |
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You could use a planetary gearbox. |
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All bikes used to be chainless. I'm not sure where the newth
is in this idea. |
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I think earlier bikes used to be front wheel drive; e.g. penny-farthing. This one is rear. |
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Sometimes you just got to ask yourself, "has it been invented before?". |
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You know the reason why penny-farthings had the huge front wheel? If not look up mechanical advantage. While single speeds and fixies are close to a direct drive, they still have something like 1.5-3 mechanical advantage. |
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Changing gear ratios on the move was a bitch,
though .... |
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There were "farthingpennies", with the little wheel out front. As I have ranted elsewhere, bicycles are old technology that was and still is both expensive cutting-edge and simple garage-crazy. You are very unlikely to come up with something new in bicycles, and especially not new and useful. |
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Gotta calm down. Will go mash thumb with hammer. |
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The Hungarian "string bike" from the Wikipedia page in the
link is possibly the coolest and most wonderful idea I have
seen for three days. |
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Except for the rear wheels, of course. |
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"Hey, I just loaned you that bike! What happened to the back wheel?"
"Sold it. Why?" |
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Looking at the string bike I see lots of disadvantages for no major advantage (limited power stroke, lightweight cable, reliance on springs in the rear hub). |
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There are hydraulic bikes. |
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One could keep the seat where it is an replace the chain with a pedal-driven gear which meshes directly with a gear attached to the rear wheel. With this system one could still change gears, but you would have to stop completely. |
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Alternatively if you had front wheel drive you could pop a wheelie, stop the front wheel with the hand brake and change gears without losing your momentum. |
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If it is just the chainyness of the chain that bothers you, VJW, why not replace it with a belt? |
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Super minimal... so, baked.
Which means the idea was a good one.
so [+] |
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Baked is not necessarily equal to good. |
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Besides, the super minimal does have a gear hub, and what looks like it has to be one of the worst riding postures I have ever seen. Way to much weight on the arms, to much of a forward lean at the saddle, and horribly short leg extension. The end result of which would be sore hands, numbness in delicate areas, extreme rider fatiuge in very short distance respectively. |
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Not to mention it doesn't look like you would want to ride up anything more than about a five degree slope at speed, or you're going over backwards. |
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Also no lights, mudguards, luggage provision - minimal yes (though less minimal than a unicycle), suitable for urban use, no (also less useful than a unicycle I would think). |
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How about a friction drive? Leaning forward on the handlebars moves wheel with pedals backward to rub directly on rear wheel. Lean back and disengage pedalwheel for coasting. This way you could easily go backwards and forwards too. |
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Standard pedals and sprocket drive directly
meshed transfer gear which drives epicyclic
gearbox positioned behind and below
crankcase. |
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Epicyclic box output drives 2 coupling rods or
bars set out of phase to prevent "centering".
Coupling rods drive cranks on rear axle
which contains freewheeling hub. |
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Gearbox can be detached for servicing
without removing wheel. |
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Sprockets are enclosed, thus protected from
environmental damage and can be splash-
lubricated (losslessly). |
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Has anyone ever made a shaft drive bike? You could put a CVT on it. I think I found my summer project. |
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Ah, I see there are. Nevertheless, still no CVTs. |
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