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Old 08-01-07, 05:49 AM   #1
stevegor
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rohloff hub in a R20??

Has anyone done this?
Please explain how.
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Old 08-02-07, 06:39 AM   #2
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That's like putting a Tuned Porsche 911 unit into a 1200 Volkswagen!

So you're thinking beyond the SA 8 speed then?
You'd need to spread the dropouts properly, find a way of fitting all those shifting cables (Well two instead of one as well as rear brakes) and possbily have to fit a tensioner...(?) More on tensioners in a bit.

As you know I've not done this myself,. but have dreamt about it... As far as I can tell - there are two ways to fit it - if you want to keep the original diamond-shape 'horizontal' R20 dropouts, you'll have to fit the bigass torque-arm to the non-drive-side chainstay to stop it forcing it's way out of the slots. The other way - perhaps more work but possibly more elegant, is to retrofit some sliding Rohloff-compatible dropouts that apparently hold tightly enough to the hub so as not to need the torque arm. Since both make use of non-vertical dropouts I can't quite see where you'd need the tensioner. Is this purely for bikes with double or triple chainrings up front maybe? Anyone?

Picture of a Rohloff-specific sliding rear dropout (from this page)


This sounds like a fabulous project for Helen's tourer (is it really *hers*? ) - I'm sure you'll keep us informed if you take the plunge. I think it'll be a first...
h

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Old 08-02-07, 07:25 AM   #3
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LittlePixel,

What set me off on this wild idea was a recent visit to my LBS where I spied a brand new Birdy bike out the back. On closer inspection I noticed it had a Rohloff hub...very nice indeed.
What you Euros and Americs need to realize is, that this is so rare a sight over here in the Antipodes that it's like finding rocking horse poo..... AND the lady who bought it paid only $2000au. A hub itself costs at least $1500au here, so I don't know how she did it.

Hmmm..... a $1500+ hub in a $15 recycle yard junker.....sounds like a crazy idea.
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Old 08-02-07, 10:02 AM   #4
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Hmmm..... a $1500+ hub in a $15 recycle yard junker.....sounds like a crazy idea.
Never heard of the Millenium Falcon? She made the Kessel Run in "less than twelve parsecs".
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Old 08-02-07, 12:49 PM   #5
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Never heard of the Millenium Falcon? She made the Kessel Run in "less than twelve parsecs".




Scene : The Emperor, (LittlePixel), seated at his throne, with a brand new Rohloff Speedhub by his side, he notices with glee that Stevegor Skywalker stares longingly at the Rohloff....
The Emperor pats the desired hub with his withered hand :

The Emp : Ahhh, you want this.....don't you, my young apprentice?
Stev: : NOOoo the S/A 8spd will do
The Emp :TAKE IT and with it...strike me, (and all the folding riders on this forum), DOWN.

Stevegor pauses to reflect on the magnitude of taking the Rohloff......then he hears a deranged voice in his head:

"Spread the forks, Stevegor......spread the forks"


Please excuse my lunacy.
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Old 08-02-07, 03:51 PM   #6
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Quote:
Originally Posted by LittlePixel View Post
The other way - perhaps more work but possibly more elegant, is to retrofit some sliding Rohloff-compatible dropouts that apparently hold tightly enough to the hub so as not to need the torque arm. Since both make use of non-vertical dropouts I can't quite see where you'd need the tensioner. Is this purely for bikes with double or triple chainrings up front maybe? Anyone?
Yes, true, if you have horizontal dropouts you could theoretically get away without the torque arm and the chain tensioner, which would definitely save on some weight. The caveat here would be for bikes with rear suspension, or whose rear triangle pivots under the bike, in which case the change in distance between the BB and rear hub might create or increase the tendency for the chain fall off. In those cases, even with horizontal dropouts, the tensioner would be necessary. (I know those don't apply to your R20.)

As far as fitting OEM style dropouts, that would mean engaging the services of a competent frame builder to modify the frame, so add that to the cost of the Rohloff. It would also mean that you are stuck with the Rohloff, as the frame has been rendered useless without it (except for SS/Fixies ). Perhaps someone has designed dropouts which are compatible with both standard derailleurs and the Rohloff, but I haven't seen it.

When I put a Rohloff on my Jetstream XP, I went through these mental gyrations as well. I elected to go with the torque arm and chain tensioner in spite of the added weight, not because I was worried about the retrofitting of a standard derailleur back onto the Jetstream, but because I expect the Rohloff will outlast my Dahon, and I want to be able to easily migrate it to another frame in the future.

Rohloff provides lots of information, including technical drawings for dropouts, here. They even provide the dropout specs in .dxf format for your friendly neighborhood CNC machine shop. (!)

Good luck and keep us up to date on your progress.

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Never heard of the Millenium Falcon? She made the Kessel Run in "less than twelve parsecs".
FWIW: That line has long been a source of some consternation among my fellow co-workers and me. (I have been doing special effects for movies and TV since 1983. We're all geeks, and recite these movies in toto in our sleep.) A parsec is a unit of length/distance, but Han is using it as though it were a measure of time. The debate has raged for decades.
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Old 08-02-07, 04:38 PM   #7
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The debate goes on foe decades with my geek friends as well. But, According to Wikipedia:

Solo in A New Hope brags that the Falcon made the Kessel Run in "less than twelve parsecs", referring to his ability to move the ship closer to the Maw's black holes and therefore cut the distance traveled. On the A New Hope DVD audio commentary, Lucas comments that, in the Star Wars universe, traveling through hyperspace requires careful navigation to avoid stars, planets, asteroids, and other obstacles. Since no long-distance journey can be made in a straight line, the "fastest" ship is the ship that can plot the "most direct course" through space, thereby traveling the least distance. Solo's twelve-parsec Kessel Run is depicted in Rebel Dawn by A. C. Crispin.

Making sense?
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Old 08-02-07, 06:18 PM   #8
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I've heard all that before. Always sounded like a lot of back peddling. I agree that the line can be interpreted that way. But I seriously doubt that such thinking was present at the time it was written. In the context of the script there are no other points where Lucas writes so far over the audience's head, so it makes the likelihood that such is the case here pretty small. Just one man's analysis. YMMV.

Even minds as great as ours can agree to disagree, given the seriousness and complexity of the issue.
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Old 08-06-07, 07:12 PM   #9
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As I've said before, "It's best not to keep track of what you are spending when upgrading a "Twenty."

A Rohloff would be taking the concept to the limit.
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Old 08-07-07, 06:52 AM   #10
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As I've said before, "It's best not to keep track of what you are spending when upgrading a "Twenty."

A Rohloff would be taking the concept to the limit.

Yes....but if I did get a Rohloff then I'd probably want a Schlumph mountain drive next
and hydro disc brakes and.....and....
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