Campy RD Question

[eolson124]

While riding Saturday in Manhattan, a plastic bag became snarled in my Campy RD, which locked up. The RD tore away from the frame's hanger (which thankfully was not bent) and got caught in my rear wheel breaking two spokes.

When shopping for a replacement RD, I note that campy changed the SR/Record/Chorus shifters and RD in 2015. Thus, I'm looking for a RD from the 2009-2014 era. Does this sound correct?

Also, this bike is built up with a compact crank (50/34) and a 12-29 cassette. What cage designation (e.g., short cage) applies?

Thanks in advance.

[R3awak3n]

Originally Posted by eolson124

While riding Saturday in Manhattan, a plastic bag became snarled in my Campy RD, which locked up. The RD tore away from the frame's hanger (which thankfully was not bent) and got caught in my rear wheel breaking two spokes.

When shopping for a replacement RD, I note that campy changed the SR/Record/Chorus shifters and RD in 2015. Thus, I'm looking for a RD from the 2009-2014 era. Does this sound correct?

Also, this bike is built up with a compact crank (50/34) and a 12-29 cassette. What cage designation (e.g., short cage) applies?

Thanks in advance.

wrong forum but I do have a 2009-2014 era record derailleur. Its not a beauty queen but works fine. Its the silver/carbon one. PM me if you want me to send pics.

[weiwentg]

Yikes! A plastic bag?! That's it? Hope the frame is OK and no major damage! Others who are more knowledgeable should confirm, but I believe you're right, 11s RD and shifters prior to 2014 have to go together, according to Campy.

https://farm6.staticflickr.com/5572/...78ca7934_b.jpg

Anyway, a rant now. The other day, I advertised a broken 2004 record 10s RD for parts. The carbon face plate broke. I had just installed a new KMC chain with quick links. As I rode off afterward, the derailleur broke and wrapped around the cassette. Derailleur hangar bent, but it's stainless steel and was successfully cold-set back. I had a spare Veloce 9s RD.

Plate cracked right through one of the screw holes, FWIW. I can't rule out user error, but the chain didn't break and the quick link was installed correctly. I removed one pin to shorten it by a few links, but no re-joins. It's possible I routed the chain wrongly around the derailleur cage; I didn't check this thoroughly, but I didn't hear anything rubbing against the cage.

I know that 13 years out of an RD is good. But personally, I'm not so favorably inclined to too much carbon on the derailleur. People will replace their stuff if and when it fails, not at a set interval, and no such set interval has been published.

So, then it comes down to failure mode. I think, after hearing of a few broken carbon face plates, and seeing one broken Record carbon FD, that maybe carbon shouldn't go on the face plate or on the FD cage. If it fails that way, the RD goes haywire. The guy whose FD failed had his chain wrapped big time around the stays. Derailleur pulley cage seems like it should be OK; can't see a failure scenario that sends the derailleur anywhere it shouldn't go. Composite knuckles a la modern Potenza, not sure.

[velofinds]

I don't have an answer to your question(s), but this has happened to me before so I know how you feel C Record RD post-(expensive) incident:

[Ronsonic]

Originally Posted by weiwentg

Yikes! A plastic bag?! That's it?

Plastic bags are deadly if you pedal through. They'll easily destroy a rear der. More dangerous than squirrels.

[oldpotatoe]

Originally Posted by eolson124

While riding Saturday in Manhattan, a plastic bag became snarled in my Campy RD, which locked up. The RD tore away from the frame's hanger (which thankfully was not bent) and got caught in my rear wheel breaking two spokes.

When shopping for a replacement RD, I note that campy changed the SR/Record/Chorus shifters and RD in 2015. Thus, I'm looking for a RD from the 2009-2014 era. Does this sound correct?

Also, this bike is built up with a compact crank (50/34) and a 12-29 cassette. What cage designation (e.g., short cage) applies?

Thanks in advance.

Use any 11s rear der with great success, even 2015/6/7...like the pro and post 2000/1 gig, it's over blown. Use a standard cage, works great. I had a compact/12-30/11s on a demo bike for years..works fine.

[weiwentg]

Originally Posted by oldpotatoe

Use any 11s rear der with great success, even 2015/6/7...like the pro and post 2000/1 gig, it's over blown. Use a standard cage, works great. I had a compact/12-30/11s on a demo bike for years..works fine.

Do you mean B compatibility, kind of like Shimano cassette on Campy shifters/derailleurs after some cable stretch and chain/cassette wear, or close to full compatibility?

Also, while we're on the subject, the Campy manual says that 2017 Potenza shifters and derailleurs are not cross compatible with Chorus+. Different RD spring tension to account for different shifting mechanisms, as I recall. Any insight into how flexible this is?

[dddd]

I don't know quantitatively how "big" of an issue that this is as compared to the year-2000 changes to actuation ratio or "pitch" as is the new parlance in some circles...

The thing that often is ignored is the effect on maintenance interval that any mis-match will incur.

Especially as the rear cable housing loop becomes ever so slightly contaminated with use, friction here acts in both directions and magnifies the transient elongation error in the cable's effective length over the entire 70" length of the cable plus the cumulative housing length. So what worked well enough when the cabling was new and perfect may still work, but now the shifting behavior begs for adjustment compromises between the positioning at either "end" of the cassette.

It's often pointed out that floating pullies correct for shifting error of this sort (as do the clearances between inner and outer links and between inner links and pulley teeth), and it may still be possible to adjust to achieve quiet running over every cassette cog, but it's the behavior during the shift that suffers noticeably when any sort of compatibility error is incorporated in the build.
Especially with today's narrow cog spacings, while riding amongst spirited training buddies or competitors, who wants to put up with any shifting hesitation or even momentary skipping or clatter of the drivetrain?

This (my first in crabon) Colnago was recently bought in a just-crashed condition for $1k, and had yet to receive any cabling maintenance in over a year and 2k of riding. But after only fabbing a replacement for it's broken derailer hanger, and replacing it's broken adjuster barrel, it shifts perfectly to/from every gear, in both directions, still just like a new bike.
I figure that this is the way parts should work, and continue to work. As for this bike's frame (claimed by Colnago to have the laterally-stiffest front triangle along with the biggest spread between vertical compliance and lateral rigidity of any frame they have made to date), I quickly noticed the stiffness for better and for worse in the front end, and it does steer and hold a line with the lowest of mental and physical effort I have to say. And, even as hilly as it is here in the foothills of the Sierra, the gearing spread of this "endurance" bike seems just ridiculous.