Is compression an issue with the rear derailleur housing loop?
 

I am installing a C-Record Chorus rear derailleur (B position) to try out the Syncro shifter for this model; I'm thinking it should shift better due to it being a slant parallelogram. The first thing I noticed is due to it being a drop parallelogram it needs a rear loop rather than the short SS coil housing. Since I used white housings for the brakes, I wanted to use it for the derailleur loop, but it is brake cable. I know that derailleur specific housing appeared long after derailleurs were in use, but I'm still wondering if some derailleur specific housing would make any difference?

Below is the derailleur in the A position before I switched it for a Super Record several years ago.

http://bikeforums.net/attachment.php...hmentid=332103

Generally speaking, compressionless housing will improve indexed shifting, but will have no benefit for friction shifters, and should never be used for brake lines. Usually it's only really important for brifter/ bar end setups. Sheldon Brown explains in detail

Syncros, being quirky things they are, may benefit a whole lot if you're running in indexed mode. Then again, that short run of housing might make no difference at all. But, the only way to know for sure is to run control tests and post your findings here!

The steel spiral housing provided by Campy back in the NR days if not before is pretty much compressionless, compared to brake stuff of the day. But I use modern brake housing on vintage bikes, and I think it improves the smoothness and precision of friction shifting. Less feathering back and forth when trying to precisely get into a gear.

Is this the derailleur your talking about? I don't think it is a Chorus but an early Athena. Chorus had a screw to adjust the "B" tension, Athena had the more common adjustable "B" tension insert like used on Victory.

Also you may want to get some dropout adjuster screws and move your rear wheel close to the front of the dropout.

The original Chorus from the Syncro days. http://velobase.com/ViewComponent.as...=108&AbsPos=25


The original Athena, again also from the Syncro days http://velobase.com/ViewComponent.as...=108&AbsPos=14

Yeah my bad, I clicked on the wrong picture when I uploaded it; here's the Chorus I was talking about.

http://bikeforums.net/attachment.php...hmentid=332149

As far as the insert goes, indeed I picked up the right one for the 7 speed Chorus in the B position (black). The freewheel is a Regina 7 speed Synchro and the chain is a Sedis Sport. Also, why would I want to move the axle forward? Actually I just removed a set of dropout adjusters because 1) I not so sure they are needed and 2) I ordered an NOS set that are Campy short dropout specific..

http://bikeforums.net/attachment.php...hmentid=332704

Normally the rear axle is centered over the mounting bolt for the RD. I don't recall the exact dimensions but I believe there was something specific for Super Record era and since Chorus is still based on that is seems to make sense. If you max cog isn't over 27T you don't really need to use the B position.

As others have mentioned Synchro was finicky and once I learned it was never going to shift like Suntour I learned to over shift and use the clicks more as a guide rather than simply relying on clicking. I eventually went to Retrofriction.

You had to overshift with the Synchro??....That's kinda screwy:twitchy:.... No wonder Shimano got that very good foothold back then to "rule the world" (with big echo)!.....

Yes, and you had to make a conscious effort doing it. Shimano really slammed the door on everyone in the 80's, their 2 keys to success where the 'G-pully' which moved laterally ans indexing levers which sprung back when over shifted.

It was a massacre...

In the Dancing Chain the author talks about Campagnolo refusing to copy anything from Shimano until all else failed and they were almost ruined. Enter Ergo and more like the second generation Ergo.


It is a great book, some of the older stuff can be boring but when you get to the '70, '80s and '90s and see how close some companies like Campi, Schwinn, Raleigh (well and some of them went over the edge I guess) it gets pretty good.

I am not under any illusion that Syncro is ever going to index without issues; originally I had the Athena derailleur with the Syncro shifters so I knew what to expect. I just noticed that because the Chorus is a drop parallelogram, unlike most Campy derailleurs through C-Record (except Ralley), so I reasoned a longer housing loop would work better than the shorter SS coil. I had hoped that Syncro might work better with the only slant parallelogram derailleur Campy released to that date with a Syncro insert for it; unfortunately, it doesn't seem to work any better but I'm going to play with it some more. This was just an experiment anyway. The Syncro doesn't fit the rest of the bike which is now almost all SR, I just wanted to see if I could make it work.

Just to let you know I pulled the wheel forward a bit and lo and behold it shifted much better; thanks for the suggestion. As far as the A-B position, I figured the B position- 30 deg slant look more contemporary so I thought I would try it first, even though I am using a 24t max cassette. Anyway I just ordered the A position insert.

Nice set up, what color insert are you using in the shifter? I have the same set up on my Mondia, Athena RD, Regina Syncro 90S 7 speed freewheel, Blue 7 speed insert in shifter, SRAM PC870 chain.
I tried both, regular housing and compressionless, the later shifting much better. You have to over shift just a bit, but it works really well.

This is when I first tried a shimano Freewheel, and a few different inserts in the shifter. Silly me, all the answers were in my Southerlands Sixth Edition. Green insert for Shimano , blue for Regina Syncro.
http://i1128.photobucket.com/albums/...Prestidge6.jpg


http://i1128.photobucket.com/albums/...Prestidge2.jpg

BG, minor point - the A and B markings are for rotating the parallelogram so that it can have a straight position like an NR or SR, or a slanted position like a SunTour. I think the slant parallelogram design was still under patent protection in those days, so companies had to be tricky about how they competed with it, or pay up to SunTour. Example: DuoPar.

No, the Suntour patent expired in 1984 and the Campagnolo Chorus came out in 1988, Shimano OTOH was waiting in the wings with their SIS system; the slant parallelogram combined with their Centeron pulley was released in 1985 and took the market (it should be noted that Shimano used the drop parallelogram for years, which resembles the slant parallelogram but still used an in-line parallelogram as to not violate Suntour's patent; when Campy released their Rally derailleur that used the same drop/ in-line parallelogram the European market scoffed thinking is looked like a Japanese design, which explains why Campy redesigned it as a drop in-line parallelogram for V2) . Campy was very slow to adapt the slant parallelogram, and released several in-line parallelogram innovations with their C record; the Athena lateral slant parallelogram and Croce d' Aune sliding control arm. The Chorus was a slant parallelogram in either the A or B position, the A position have a 5 deg slant and the B a 30 deg slant.

YES! And not only that, it is going to shift better with 4mm housing than with 5 if you are using a 1.1 or 1.2mm cable. Anyone who thinks housing isn't important hasn't worked on many modern drivetrains. Maybe you can get your syncro working fine with brake housing but it is going to work better with proper shift housing.

Re: the sub topic that has started about indeed shifting... someone in another thread was saying how campy got it right with ergo from the get go... and I was thinking.. "really!? you think so". Even in the early 2000s ergos shift performance was STILL inferior to the light action and precision of shimano.

I know we've had this conversation before, but I will try one more time. The below is the graph you were referring to was taken from the above graph as an example how it would work. The inserts are matched to the derailleur and the graph shows which freewheels will work with the insert, not which insert will work with which freewheel; no matter which freewheel you use, the insert will always be the same for the particular derailleur. Below is shows the 7 speed Athena/Xenon derailleur requires a blue insert and will work with a Campagnolo approved 90-s 7 speed freewheel and the others listed above. The 7 speed Chorus derailleur requires a green insert and will work with a Shimano SIS 7-speed freewheel/cassette and others listed above. The above graph also shows which chains work best with which freewheels.

Edit: actually the below graph adds two freewheels to the above graph.

http://bikeforums.net/attachment.php...hmentid=332705

It's right on the chart you posted, one more time.......inserts match the freewheel. Look on the right side of the
Chart.

The important part is you ended up with the blue insert for the Athena and your with a Campagnolo approved 90-s 7 speed Synchro (BTW Campy spelled it Syncro and Regina spelled it Synchro) freewheel! To answer your question, according to the graph there are two different color inserts for Chorus depending on which position you are in A=green or B=black. With the Athena (with a Campagnolo approved Regina 90-s 7 speed freewheel), as with you, I used the blue insert. With the Chorus (the same Campagnolo approved 90-s 7 speed freewheel), I choose the B position so I used the black. I now want to try the A position, so I ordered a green.

I would like to know how that works out. I have a dual position Chorus Derailleur, so if it works out for you maybe I'll try your set up also. BTW, My Mondia shifts as good as any Shimano SIS.