I've been struggling a bit with the angle of the dangle of a Nuovo Record derailleur I put on my Gitane TdF using my custom parts. Fine tuning it and using some NOS Simplex stop plates I obtained. I took a protractor to my two bikes that have Record derailleurs on them and note they both sit at approximately 63 degrees in relation to the chain stay. My question is, does this angle seem written in stone for single parallelogram rear derailleurs, and, why is it important? I presume Campagnolo designed their dropout notch for the derailleur to sit at exactly this angle. What does it affect if the angle is slightly more perpendicular? Chain wrap? I got the angle more acute using my custom made stop plate but am having trouble with the angle being a bit too obtuse using the Simplex plate. Does this angle matter all that much?

Awesome title... made me go back and find the thread over the holidays about fabbing the bolt, beautiful stuff.

Your question makes me curious about what the tolerances are for brazing a drop out onto a bike, with the stays coming in at different angles with different sized frames.

Theoretically, the closer to the cassette you upper pulley is (more acute angle), the quicker and more responsive it will shift, Go too far though and your pulley will start rubbing on the larger cogs.

It is a similar situation as a B-limit adjustment on more modern derailleurs.

Overall I doubt that a few degrees either way will have any major effects.

Seen this? https://theparallelogram.blogspot.com/

Found it a while ago, while researching the differences between Nuovo and Super Record. Fascinating stuff - I found it illuminating.

Hey. Great link, thank you! very interesting indeed. I see he measured the angles from the horizontal, while I measured from the chain stay. That said, it seems the same, 115 degrees for the Nuovo Record, or close to my 63-65 measured from the stay. I found it fascinating that the Super record changed a bit and now I'll have to go examine my example to see just how the re-designed the stop boss on the back of the upper pivot body. Thanks Ericbaker, you might be right, a few degrees either way probably won't matter too much. But you got me to thinking, maybe my 5-7 degrees more acute with the original plate wouldn't be a bad thing, effectively throwing the derailleur farther forward and, maybe, moving the jockey pulley closer to the cogs. But like you say, too far can't be a good thing. I am now altering the stop boss of another NR rear and kind of sweating going too far with material removal and ruining a derailleur! I found the Pat '72 pictured in the third photo above was a little worn in the lower body/spring cage interface so I was getting sloppy results. Trying a tighter derailleur now, but it's a little white knuckle grinding on it.

Thanks Tugrul. This has been a fun project. A little exasperating, however. Your question about brazing the dropouts is VERY interesting indeed. I hadn't even thought about that. I'd be interested to hear a frame builder chime in on that.

I'd think the angle of the stop would only matter with the smallest cog. One thing I see in your pics is the Simplex dropout seems longer to the derailler mount, which may have some effect.

Honestly, a good friend in college raced a PX10 with Campagnolo NR deraillers, he loved it! I believe he just filed the stop.

That's an interesting observation Dbakl, thanks. That extra "drop" to the dropout might move the jockey wheel that much farther away from the cogs, thus decreasing chain wrap a bit, I guess. When one gets into tinkering with stuff like this, one finds there is a lot more to it than initially apparent. I tend to over-think things, though. That info on that blog is very interesting. I'll have to go back and re-visit my Dancing Chain book and see what I can glean. I really haven't had much of a chance to test this set-up either. Wish it would warm up a bit.

!#*%!#*!!!!

I dare say the angle was chosen primarily to keep the chain gap reasonable for varied setups, not for ideal operation with any single type of freewheel.

Case in point, Nuovo Record's parallelogram angle results in inferior chaingap with a corncob freewheel. On the other hand, the same angle allows the upper jockey wheel to clear a wide-range freewheel, for if the parallelogram had been angled any farther forward, the upper jockey wheel would be more likely to interfere with the middle freewheel cogs.

Campagnolo finally figured this out with Victory, which has the three-position stop. It's mentioned in the blog that ctmullins mentions.

Funny thing - I did that as a university project 4 years ago. I should move it over to The Headbadge.

-Kurt

So that's your work Kurt? Very nicely done. I'm having real trouble with the current plate I'm experimenting with. My angle of dangle is approaching 90 degrees, nearly perpendicular to the chain stay, and the shifting performance kind of sucks.
Back to the drawing board.

I guess my question is, how does it shift?

Not well right now. In the 3rd pic above, I'm using my custom made nickel silver plate and have much more of an angle to the derailleur, but I'm trying to make a plate out of a NOS Simplex one, 'cause the custom made one was a royal pain, but it's not working too well. Requires a lot of over-shifting and getting into the lowest cog is real trouble. Kind of like a Nuovo Record ...only worse.

I also dare say.

That was you? (where's the bow-down smiley?)

I have big plans for a Triomphe and a Dremel based on your work.

Personally, I daresay, but to each his own.

Ummmmm, I've never used a high-end Simplex derailleur which used a stop, but the old Prestige had a spring at the top and the bottom so the position of the parallelogram and therefore the jockey pulley was never deterministic. Rather, it was the balance between the upper and lower pivot springs. Of course that might explain some of its unpredictability, but that feature per se never seemed to be an issue. But what to I know?

I had a Triomphe RD that did that on a Raleigh USA dropout.

FYI, Campagnolo's claw hangers have a radically different angle - Pastor Bob's blue Continental has an example of this.

That was me. I put more effort than I realized in that page.

Don't tell me - you're going to grind the stop down. A good file should do the job too.

-Kurt

Kurt. A bit more info, if you please. Do the claw hangers put the derailleur angle much more forward than the standard Campy hanger?
And does it follow that if a standard Campy dropout hanger would allow the derailleur to rotate further forward, within reasonable parameters, it would improve performance? Of course, I can't use a claw hanger in this application. Tried it, and that's what started this whole project in the first place. heh

Here's a 100% scan @72ppi of the Campagnolo claw if it helps...

Approaching Victory's 135 degrees or more. Bob has a great photo of it somewhere around here, but I can't find it. I Googled "pastorbobnlnh nuovo record" only to find half a dozen of my pictures.

I did find this; not the best picture for the RD angle, but you can see it sits quite far forward:



Edit: BINGO. I don't think the Continental's dropout angle helps any either. The Nuovo Record pulley cage wasn't designed for this angle in mind - ideally, in this configuration, it would work better with a Super Record pulley cage (which has the same geometry as Victory).



With certain ratios, this is possible. If nothing else, it'll help alleviate low-gear chainwear through better chainwrap.

-Kurt

Thanks Dbakl. As a matter of fact, I have one of those, and tried it initially, but it won't work on a Simplex dropout. Simplex hanger interferes with claw and it placed the derailleur too far outboard anyway. That's when I decided to try to make my own custom bolt.
So, I was never able to try the claw and see what kind of angle it produced, other than a cursory test fit.

Thanks Kurt. Yeah, that angle on the Continental looks like a bit too much the other direction. I'm sitting at about 95-100 degrees now, which, combined with the extra length between the Simplex hanger hole and the center line of the dropout ....more than the Campy dropout...I'm getting lousy chain wrap. Guess I'll have to go back to my custom made plate until I figure out how to cut this Simplex plate to work, if possible. Thanks guys.

Oh, I just thought you could use the shape to calculate where to place the stop. BTW, how is it shifting poorly? If noisy, I find many times the cage on the NR is tweaked and the jockey wheels not aligned with the cog, chainline. Once you've squared the dropouts and hanger of course...

Chain length good?

Is it you don't want to modify the Simplex dropout that you don't tap it and file it?

Honestly, it doesn't take much to get a friction rear derailler to move side to side and change gears. The stop only seems to keep the derailler from rotating too far forward in the highest gear. In most gears, there's no contact.

Draft out the dimensions of your custom plate, and see if Henry III can laser-cut a few of them for you.

-Kurt