I've been thinking about something...
 

...and I'm curious if anyone has ever thought of it.
Okay, as we all know Suntour kicked butt in the 70's and 80's 'cause they had the "slant parallelogram". That's great, and it was great, since every manufacturer has copied it, nowadays. But, has anyone ever explored this thought, or better yet... done it.
Has anyone ever taken a "claw adapter" for bikes sans derailleur hanger, bent it about 15 degrees outward (or however much a slant parallelogram slants outward), and attached a straight parallelogram RD to it? Here's a picture as an idea of where I think bending would work.
http://lh6.ggpht.com/_Os80BGPtmH8/TD...law%20idea.jpg
I'm just wonder if this could be a simple way to make a Nuovo Record (or other similar straight parallelogram) rear derailleur work better, if only by copying the slant principle. I'd do this, but I lack both the claw and a NR RD. But maybe another member will be intrigued about this and do it.
Just an idea/conversation starter. If you don't think it'll work, tell me why. I just figure it would be interesting to try, and might actually help NR's shift better.
-Gene-

Campy already copied the slant idea. I have one of these.

http://velobase.com/ViewSingleCompon...d-b2a3cf313619

I keep it because it is art but to be honest a cheap shimano works better - I never had any problem shifting this but a lot of folks hated it. It really needs to work with a downtube shifter though for the "feel" as their is some technique involved.

Either way - you need the long cage to take up the chain anyway. The NR worked perfectly fine on a straight block - it was not intended for wide gearing. Why would it need to "shift better"?

Anway that site has some other versions where Campy tried several approaches.

Those weren't slant-parallelogram, just drop-parallelogram. The first-gen Rally is one of the most beautiful derailleurs ever made IMO, but it definitely isn't slant, it couldn't be, Suntour would've sued the crap out of Campagnolo at the time for that.
And why would it need to shift better? Cause all I've ever heard is that it's clunky and shifts like crap on anything but a straight block, which not everyone uses. I have no first hand experience with one, but would gladly try one if given the opportunity.
-Gene-

Ok - I have owned two Nuovo Records and never had trouble shifting them but I was not a bike racer and under race pressure I cannot answer. They were ok derailleurs and classic for their time. But there are better things out there now and, to me, that is the answer.

Technically you have me on a design detal and the Rally was Campy's answer to the Shimano Crane, but not understanding how what you are proposing would function as a slant parallelogram.......

To say you have *heard* something shifts like crap is a lot different than actually having owned and shifted them and making your own opinion. I think in light of what else was out there at the time, the Campy's were pretty ok. I think maybe folks who grew up with index shifting may not have the feel for the old downtube friction shifters.

The cage will be at an angle if you bend the claw. Do you think that will work? I don't.

No it would not work as the jockey and pully wheels would no longer be in line with the freewheel cogs. They would be at an angle and chains don't take to twisting like that.

Size limitation would still exist due to limited takeup anyway.

Nice to see someone thinking though.....................................that is how things get improved.

That's what I didn't think of, thanks for that.
It was just an idea I had, I just needed to see if there was any reason it wouldn't work.
-Gene-

See attached...
You could design the RD to have the parallelogram swing through an angle skewed to the right but it would require more metal and be heavier. It would also stick out further. I would expect that Campy thought of all that and rejected the idea.

EDIT: Whoops, I see you're referring to slant parallelograms. When I wrote this post, I was thinking of turning a straight parallelogram into a drop parallelogram. Disregard.

René Herse already did it - it's on his 1980 Tandem Chanteloup as shown in The Golden Age of Handbuilt Bicycles. The hanger is a Herse-fabricated piece which sits lower than a conventional hanger. I believe with the derailer stop was rotated 40 degrees or so, counterclockwise.

This made a straight-parallelogram rear derailer sit in the same location as a drop-parallelogram; in the case of this 1980 Herse, the RD is a Simplex Super LJ 5000 long-cage.

I'm not sure if this is the same '80 Chanteloup, but you can just barely make out :

(Those of you with the book will see a better photo of this RD setup on page #158 and #161; the 1962 Chanteloup on page #160 has a much shorter hanger with a Huret Alivit running in the conventional manner).
http://www.reneherse.com/images/schott1726web.jpg

-Kurt

oh my that is a LOVELY bike.

There's just so many wonderful details to ogle :love:

Suntour's engineers had a better idea.

Campagnolo tired lots of stuff to find an alternative to the slant parallelogram, if you search the patent applications in the late 70's to mid 80's they were very active in attempts. Not much made it through to production, the chorus adjustable parallelogram did and did the rod mechanism that showed up on the Croce d' une, (sp) If I remember correctly.

They were mad about whole wheels too, and that did precede their entry into the complete wheel market.

I think the beauty in the Suntour design was how the angle of the parallelogram allowed the wheels to stay close to the cog instead of just in and out. It was a simple and elegant design. They won. They build the better mousetrap.

The compromise in the Rally first gen design is in the rotation or the pivot point at the frame attachment. I don't know what they were smoking when they made gen 2 unless Shimano got onto them.

As the chain is slackened the jockey wheel goes forward which takes it in closer to the smaller cog. As it tigtens it goes back but the problem is that the front chainrings influence the tightness of the chain and the relative position of the jockey wheel whereas in the Suntour design that position is based on the derailleur itself.

Perhaps I never had a problem shifting with the Rally because I never used it with a triple but only with a standard 42/52 chainring combo and I only crosschained once through the entire gear sequence on the middle cog. Of course I also never shifted it under pressure. I know when we built our tandem we used a Suntour :)

Yep. That's Herse for ya (and Singer as well). And that's why a randonneuse from either builder would be my "grail" bike.

SP
Bend, OR

I experimented with a Nuovo Record with a Rally cage. It's essentially a second generation Rally, only prettier. I hated the way it shifted and replaced it with a Suntour VGT Luxe. My search for the best shifting vintage long cage derailer is over.

http://inlinethumb01.webshots.com/30...600x600Q85.jpg

This Sachs/Huret was a close second, but it's a much later knock off of the Suntour design.

http://inlinethumb10.webshots.com/33...600x600Q85.jpg

I've recently been drooling over the modern Rene Herse badged bikes over at renehersebicycles.com

Hey - I think I was smoking something - I know the Rally worked for me as did the Nuovo Record even though there is better stuff but here are some videos.

I was a bit off on my description of how the pivot works. Here is a Rally and a Nuovo Record

http://www.youtube.com/watch?v=I0maUcy2W4A
http://www.youtube.com/watch?v=DDEv51xzBZ4&NR=1

And compare with a suntour
http://www.youtube.com/watch?v=-EaCLUkK52w

I recognize the author of these fine videos on this forum

I'm embedding the videos for you:

Rally first-gen:

Nuovo Record:

Cyclone 7000 (my favorite indexing group):

-Kurt