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Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

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Old 09-22-10, 11:21 AM   #1
puppypilgrim
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StringBike. No chain, just strings.



From Rohloff to Pinion to Strings. :-)

Appears to have 19 speeds and can be shifted while stationary. Total range of 250%. Wide Q-factor. No dishing needed for the wheels. Due to symmetry of drivetrain, perfect alignment of drive components. The drive does not require lubrication or maintenance and uses a polyethylene rope.

Left and right sides do not need to use the same gearing. Therefore if one has a disability, a bike could be tailored to meet asymmetric strength requirements.



How It Works
http://www.stringbike.com/principle-of-operation

How To Change Gears
http://www.stringbike.com/Change%20of%20gears

How Efficient Is It?
http://www.stringbike.com/Efficiency%20of%20the%20drive

How Does It Feel Compared to a Chain Drive?
http://www.stringbike.com/Driving%20curves
http://www.stringbike.com/Smooth%20driving

Last edited by puppypilgrim; 09-22-10 at 11:45 AM.
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Old 09-22-10, 12:54 PM   #2
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Intriguing! I'll be interested to hear the engineer types on this board weigh in.
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Old 09-22-10, 01:02 PM   #3
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in before the engineer debate
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Old 09-22-10, 02:44 PM   #4
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Those cams make it look sort of like a compound bow. I'll pass.
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Old 09-22-10, 03:06 PM   #5
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Very interesting.

As always, I am curious about the efficiency numbers (not wordy descriptions). As usual, there are no numbers.
It looks like it has the capability to be made really light. The current design seems heavier than a derailer system. The rear hub needs work for this.
Looks like it could be almost completely dirt-proof.
It looks like it needs a special frame.
It uses lots and lots of extra bearings.
It uses far fewer bearings than in a chain.

The inventors need to show not innovation but a clear improvement on what is already available, from efficiency, cost and weight POVs.
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Old 09-22-10, 03:28 PM   #6
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I don't know if its a better mousetrap.

Website says no lubrication or maintenance is needed. Seems to have complex moving parts to me. And complex to me is not so good but what do I know? The pedaling feel is not like a chainring. More of a lever action. Nothing wrong with the innovation I suppose. The only thing that would need replacing over time is the string\rope ad bearings. The hub would last the life of the bike.
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Old 09-23-10, 08:44 AM   #7
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Thank you. Good share!

I've got a few questions though.
Are'nt there springs in the rear hub to return the strings and crank to the pre-power delivering phase?
And won't this "return" tendency zap rider energy by acting in the opposite direction of rider applied moment?
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Old 09-23-10, 08:48 AM   #8
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1. Seems to me I saw something very like this in a transportation museum in Germany... on a bike from the turn of the last century.


2. And it folds... how?
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Old 09-23-10, 09:30 AM   #9
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Quote:
Originally Posted by rhm View Post
1. Seems to me I saw something very like this in a transportation museum in Germany... on a bike from the turn of the last century.
Which just goes to show once again that all major innovations in bicycle design--including ones we think of as very modern--were originally developed in the 19th century: folding bicycles, internal gear hubs, shaft drives, etc.
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Old 09-23-10, 07:31 PM   #10
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In all of the videos with someone turning the cranks by hand the motion looked very jerky. I think belt drive with an internal gear hub gives the same advantages without so many parts.
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Old 09-23-10, 08:06 PM   #11
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True Smallwheels. Simpler and cheaper. For me though, I think a singlespeed chain drive is still tops for ease of use and maintenance.
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