jan nikolajsen 

Thanks a bunch for the detail shots, John.

I just need one thing clarified: the tabs on the washer in lower photo are off set 90 degrees compared to the ones in the top image. I suspect the lower one is from a different derailer?

Jan

JohnDThompson 

Darn it, no. That's the difference between the 2 types of tab. Somehow I got 2 Huret type tabs in that first shot.

Antipodes

The Duopar is a great derailleur. I had originally had one on my touring bike when it was still friction shifting. It was mated to an old Suntour 14-34 freewheel with a Shimano IG chain and Shimano 8 speed barcons and the shifting was undoubtedly the best I have ever experienced from a friction bike.
I like how you can simply disengage the parallelogram spring by pulling it away from the tab stop. It's a nifty little feature.

23skidoo

I'll contribute here if anyone can tell me if this one is properly assembled. It was original equipment on an early-80's Trek 720 and had been replaced with a Deore; it was in pieces and I think this is how it all fits but I'm not sure. It's a Sachs-Huret Duopar and is this the titanium model? The rear plate on the cage has a bluish tinge and I've never seen metal jockey wheels like this before.



More pics here:

https://s270.photobucket.com/albums/j...uret%20Duopar/

JohnDThompson 

It looks like you have all the important pieces. The should be a plastic plug that fits into the hollow mounting bolt, but it's just there for cosmetic purposes.

The jockey wheels look like 3rd party replacements -- Bullseye perhaps? But the upper pulley on the Duopar was fairly unique and I don't recall if Bullseye made a Duopar specific pulley for this. I'm not sure why you'd want them anyway -- the Duopar Ti pulleys used cup and cone ball bearings rather than the sleeve bearings typical of other manufacturers (even Campy and Dura-Ace).

23skidoo

Tab up or tab down when mounting?

Panthers007

Up, as I recall. But there's a flat on my bike's brazed-on RD tab. Fiddle with it and see where it feels it should go. And yes - that's a titanium model. The Bullseye pulleys came with a bunch of washers to fit them on where there was a wider pulley up top. They were the rage back then, but they didn't do anything spectacular - aside from change the sound the RD made as the chain rolled through it. They will last a long time They are aluminum.

23skidoo

Grand Bois

The tab catches the stop on the dropout, so it goes toward the bike. The little protrusions on the back of the washers go into the notches on the derailer.

I just realized that I bought a nice derailer with no mounting bolt or washers.
I'm screwed! Anybody got a broken one to sell me? I might be able to fabricate the parts, but I don't know.

Peter_B

Shifts absolutely great BUT... as PeeWee Herman said "Everyone has a big but," ... the chain can derail off the Duopar's pulley cage when you roll the bike backwards and bind up the Duopar rear derailleur, leading to BIG problemo if you don't stop rolling the bike backwards. That's why some used to fabricate a pulley cage that captured the chain better on the upper pulley. Your mileage may vary....

Panthers007

Just for your historical elucidation: When the Duopar abruptly vanished off the market, someone had to step up to the plate. Especially considering that mountain-bikes were the rage. Everyone wanted a triple up front, and as many gears in the rear as was possible. The 18 spd. was born. And the Duopar would have been the logical choice for it's range, but it really was to delicate for screaming down mountains. Enter SunTour -

The SunTour Mountech came out around 1983, as I recall, and it had the range to accommodate the new MB rage. So we all bought one (or two). These beasties had enough range to likely handle Campy's new 11 spd. with a triple front. And SunTour was happy as they were at war with Shimano. But after raging success - it was found that the spring in the weird upper-pulley that the Mountech had would spontaneously self-destruct. Sometimes violently enough to cause crashes.

With that , and other things that went wrong, Shimano ended up winning the war. And SunTour rode off into the sunset. I still have a Mountech in excellent condition - living in a baggies. Pity - they were excellent derailleurs.

By the by, I could back-pedal and roll my bike backwards with the Duopar. Check the adjustment angle.

JohnDThompson 

See if your LBS has an old parts bin you can dig through. The mounting hardware wasn't Duopar-specific; mounting bolts from Success or Challenger models will also work.

Peter_B

There are conflicting reports I have read on listservers of no problems and critical problems in rolling bikes backwards with Duopar rear derailleurs and chain deraillment to a freewheel cog other than the cog under which the upper pulley is situated. Perhaps it is an adjustment but then those several who have reported problems didn't respond back to the listserver 'oh, you were right, an adjustment fixed it.' Given that there are much better derailleurs available, one can twiddle it as one wishes. Mine is in a box and I've moved on to better and sturdier performance. As usual, your mileage may vary.

Grand Bois

I'm sure that there are more modern derailers available that work better, but the Duopar was the best available at the time and this is C&V.

Grand Bois

Thank you for that! I'm sure it will be easier to find an old Challenger or Sucess to canibalize. It looks like an Eco will work too, since it's the same thing in all steel.
I think I'll gain a B screw if I can find a late version made for a Campy hanger.

https://homepage3.nifty.com/passhunte...uret/huret.htm

Meanwhile, I'll make do with this. It shifts like a standard NR, but I don't like the way a NR shifts. I don't want to have to
readjust after every shift. It sure is pretty, though.

jan nikolajsen 

An Eco just closed on Ebay for $122, with 17 bids. No mention of it being NOS, but it looks nice. The pictures are carefully arranged not to show the backside so I wonder if the washer is present.

Somebody mentioned in another post that Japanese collectors are fascinated with French components, and this is driving up the Ebay prices. I guess compared to two grand for an Ideale saddle, this Duopar auction is downright reasonable!

Grand Bois

This is the one that I bought. It clearly states that the mounting hardware is missing so it's my own fault.

https://cgi.ebay.com/ws/eBayISAPI.dll...ies%26_fvi%3D1

Grand Bois

I received the Duopar today. It's not so ugly in person. The body as well as the cage is titanium, according to my magnet. The titanium parts are painted. It's a complicated derailer and it looks delicate, so I'm going to hang on to the long-armed Nouvo Record. I bought a cheap Huret just for the mounting bolt and washer, so I won't be able to mount the Duopar until it arrives.

Panthers007

They are rather delicate. I wouldn't put it on a bike that was going to see off-roading more than packed dirt trails.

purevl

At the risk of offending the many europhiles in C&V I'd like to play the devil's advocate for a moment and disagree with that claim. If you agree that there are better modern derailleurs than the Duopar then I think it's a fair argument to make that it can't be the best vintage touring derailleur. Any mainstream modern derailleur design traces its roots directly to SunTour. The V series derailleurs had already been in constant development for a decade before the Duopar was introduced. There were several touring ready V derailleurs to choose from as well as long cage Cyclones. The dual parallelogram and 3 pivot derailleurs were all engineering marvels but they also all developed reputations as being unreliable and difficult to adjust. SunTour derailleurs were rugged, well designed, and most importantly they just worked, really well. What they weren't was expensive, and since their cheapness meant they could be spec'ed on bikes that were far from top of the line they weren't exclusive enough to capture the imaginations of snobbish cognoscenti of the time so their brilliance was often overlooked. It took other manufacturers another decade to catch up and to date no real improvements have ever been made on the basic design. The lowly SunTour bits may not have the cache of fancier stuff, but they looked good (in my opinion anyway), were light weight, and functioned just as well in the short term and typically much better in the long run than rarer stuff like the Duopar or hacks like the Record/Rally hybrids.

I'm not trying to insult your choice of derailleur by any means Dirtdrop, just making the case for the most under-appreciated components in the C&V world. You're willing to put up with the crummy operation of the Campagnolo piece when better options are and were readily available and it shows a bias. The Duopar is certainly very cool and I wouldn't kick it out of bed for eating crackers, but I would probably do a long tour on a nice reliable Vx while the Duopar sat on a display shelf at home.

I know that you have an affinity for exclusive and eccentric parts (most of us do) and I'm not trying to sway you, but... If pure whizzbangery is the only goal and fragility is a non issue then the Mountech seems more cleverly over-engineered than the Duopar. If class and exclusivity are the only parameters a long cage Jubilee blows the Campy away. If you've got to have geewhiz engineering and supreme unavailability at the same time the White Industries LMDS is a pure work of art. If consistent function, ease of use and reliability in the field (What to me defines "best") are top priority give me a Vx Gt Luxe, a long cage Cyclone GT, or if the 80s can play a *horrors* 3 pulley design.

That's my interjection of mechanical dorkery for the day, now back to regularly scheduled programming...

Panthers007

The Duopar was the first DUAL-parallelogram derailleur commercially marketed. At least that was the hype back then. And we all had to have a few. Why a few? See my previous post.

Antipodes

Wow. I'm off to sell mine right now...

Road Fan

[QUOTE=Panthers007;8301870]The Duopar was the first DUAL-parallelogram derailleur commercially marketed. At least that was the hype back then. And we all had to have a few. Why a few? See my previous post.[/QUOTE


I don't think there were any other dual parallelograms. If there was one, I'd think it was an even more obscure Huret.

I find it shifts a lot better than a slanted Rallye, because it shifts right away and doesn't overshift. If I pedal backwards and the cage is not well-aligned with the cog the chain is on, I can get chain jamming, and need to stop and clear it or sometimes a well placed shove with my foot will help. But no breakage.

pastorbobnlnh 

My limited experience with the debate going on in this thread:

1st Generation (slanted) Rally; horrible shifting! I spent about 2 hours trying to finesse this RD to have even mediocre shifting on the bike stand, but no luck. I can't imagine how it might work on the road. (I know, lousy picture and of course it can't shift w/o a chain, freewheel, crankset, and cables, but it's the only picture that I have of this pita RD.)


2nd Generation (non-slanted) Rally; ok shifting, with subtle tweaking of shift lever. Often skips a cog and then I need to back shift.


Sachs Huret Eco DuoPar; This basic looking beauty functions flawlessly. It only took about 10 minutes to have it set up and shift spot on perfectly after yanking off the 1st Gen Rally. I don't believe I've made an adjustment after some 1000 miles or so of riding this summer. I don't find it fragile, but I'm not riding Sporty back in the woods, either.

JohnDThompson 

The history of the modern derailleur is complex, and today's popular derailleurs owe a debt to both SunTour and Shimano, and even Simplex.

Back in the late 60s, Shimano licensed Simplex's double spring design for their derailleurs.

Here's Shimano's early "Skylark" derailleur:



Compare to Simplex's "Criterium:"




Later, they added a dropped parallelogram to allow the top pulley to track the freewheel more closely. This made shifting quicker and more precise. In the 70s, Simplex licensed back Shimano's dropped parallelogram design. Here's Shimano's top of the line "Crane" derailleur from the mid 70s:



And here's Simplex's version, from the same era:



At about the same time, SunTour did one better with the dropped parallelogram by slanting it to further improve top pulley tracking, but Shimano had a lock on the double spring design in Japan this feature was not incorporated into SunTour's derailleurs. Here's the popular V-Luxe:



SunTour and Shimano continued to develop along parallel tracks until the mid 80s when two things happened: first, SunTour's patent on the slanted parallelogram expired, and Shimano introduced "SIS" indexed shifting, which actually worked! Shimano was quick to incorporate the slant paralellogram into their own derailleurs, as evidenced by the Dura-Ace 7400, the first SIS derailleur on the market in 1985:



Alas, SunTour (and a myriad of other companies -- e.g. Huret, Simplex, Maillard, CLB, MAFAC, TDC, Williams, Gian Robert, Zeus, etc.) were unable to compete against the Shimano juggernaut, and went out of business or were swallowed by other companies. Even Campagnolo was circling the drain for several years. But this vacuum did allow for other companies, particularly North American ones, to eventually jump in and fill the void, providing much needed diversity in the bicycle ecosystem.