Campag rear mechs: technical stuff

[BigYin]

I think DaveS is correct, the only way to know for certain is to buy 11s shifters, cassette and chain and see if it works with the 10s RD.

I think, realistically, if we're going to the considerable expense of buying even just that 11s gear then we've already committed to converting to 11s. If it works with our 10s RD that's great, saved some cash. But we need to budget for an 11s RD in case it doesn't work as well as we'd like. Or to try DaveS' RD modification.

It looks like it's not possible to get a 100% definitive answer any other way. It would be nice to know, academically, the technical stuff interests me, RD actuation ratios, shifter cable pull ratios etc., but it looks like a definitive answer from that side isn't possible. Campag's line will be 'using a 10s RD with 11s equipment could lead to accident, injury or death'.

[highdraw]

I think DaveS is correct, the only way to know for certain is to buy 11s shifters, cassette and chain and see if it works with the 10s RD.

I think, realistically, if we're going to the considerable expense of buying even just that 11s gear then we've already committed to converting to 11s. If it works with our 10s RD that's great, saved some cash. But we need to budget for an 11s RD in case it doesn't work as well as we'd like. Or to try DaveS' RD modification.

It looks like it's not possible to get a 100% definitive answer any other way. It would be nice to know, academically, the technical stuff interests me, RD actuation ratios, shifter cable pull ratios etc., but it looks like a definitive answer from that side isn't possible. Campag's line will be 'using a 10s RD with 11s equipment could lead to accident, injury or death'.

What in the world are you talking about with your last sentence. Read this and read it again. A 10s Campy rear derailleur works OK with Campy 11s shifters. OK isn't necessarily perfect but OK for many is acceptable. If what bikerjulio states as true...then there is NO difference between the two derailleurs in terms of performance. But many have and do run a Campy 10s rear derailleur on a 11s groupset without issue....a matter of degree only.

[BigYin]

Tongue-in-cheek last sentence.
Finding technically perfect matches was the point, not what's 'ok' or 'acceptable'.

[highdraw]

No...that's your opinion. A lot of riders running Campy 10s rear derailleurs with 11s groupsets. Your ideal violates their sensibility. Some are ok with 'B' level compatibility as B is a passing grade. But if you like perfect I understand because I feel the same way and I have had chances to run Campy 10s rear derailleurs with 11s builds and opted not to.

[DaveS]

Something I would like to get a clarification on....using a 10s Campy rear derailleur with 11s right hand shifter. 10s rear derailleur actuation ratio hasn't changed since 2001 as noted. Many have tried it and pretty much all say it works. But...I have read that 11s Campy rear derailleurs do not have the same actuation ratio compared to 10s...they are fractionally different and NOT the same...but the difference between the two is quite slight and why a 10s Campy rear derailleur will shift a 11s driveline no problem.

Anybody have a definitive source that either supports or refutes the above?
thanks

What would you consider "definitive"? As I noted, I tried it many years ago and the 10 speed RD came up a little short on travel. A minor mod fixed the problem. All I can say for my credentials, is mechanical engineer since 1981, who specialized in machined metal products for over 20 years. IMO, if the RD aligns half way between the 10th and 11th cogs, after 10 shifts, it's not the same.

Anyone in doubt should try the procedure that I described. If your RD aligns with the big cog after 10 shifts, then it should work. If not, then try my simple modification.

[BigYin]

No...that's your opinion. A lot of riders running Campy 10s rear derailleurs with 11s groupsets. Your ideal violates their sensibility. Some are ok with 'B' level compatibility as B is a passing grade. But if you like perfect I understand because I feel the same way and I have had chances to run Campy 10s rear derailleurs with 11s builds and opted not to.

Yeah I do like shifting to be perfect, certainly on my good bike. I'm not always so particular, on my winter hack for example 'B' level is fine. Riders anecdotes on compatibility are difficult to judge, maybe a matter of degrees as you said previously. One man's perfect is another's average etc etc.

[uraqt]

DaveSv is/was the campy expert if you searched him.....

not that it matters

[BigYin]

(Idle insomniac ramblings)...
Campag tech doc's say 2011-2014 10s RD's have 'Parallelogram with 11 s geometry', so should work perfectly with 11s shifters.

We know from DaveS that some 10s RD's, pre-2011, are not perfectly compatible with 11s shifters. I think he has proven that as definitively as you can get.

Campag groupset catalogue for 2009: Chorus upwards, RD'S are listed as 'Parallelogram with 11s geometry'. Centaur and Veloce 10s are not listed the same, so I take it that they don't have the new geometry.

I conclude:
-10s RD's up until 2011 are not perfectly compatible with 11s shifters.
-10s RD's from 2011-2014 listed as 'Parallelogram with 11s geometry' are perfectly compatible with 11s shifters.

As to the anecdotal reports of old 10s RD's working 'fine' with 11 shifters; idle speculation now, but maybe it's possible the incompatibility only affects the last shift to the biggest cog? If so, the reports of old 10s RD's working with 11s shifters make sense as many riders have a largest sprocket that's kind of an emergency gear, almost never use it. Maybe the other 10 sprockets shift perfectly. Just a thought, maybe complete bollox!...

[highdraw]

(Idle insomniac ramblings)...
Campag tech doc's say 2011-2014 10s RD's have 'Parallelogram with 11 s geometry', so should work perfectly with 11s shifters.

We know from DaveS that some 10s RD's, pre-2011, are not perfectly compatible with 11s shifters. I think he has proven that as definitively as you can get.

Campag groupset catalogue for 2009: Chorus upwards, RD'S are listed as 'Parallelogram with 11s geometry'. Centaur and Veloce 10s are not listed the same, so I take it that they don't have the new geometry.

I conclude:
-10s RD's up until 2011 are not perfectly compatible with 11s shifters.
-10s RD's from 2011-2014 listed as 'Parallelogram with 11s geometry' are perfectly compatible with 11s shifters.

As to the anecdotal reports of old 10s RD's working 'fine' with 11 shifters; idle speculation now, but maybe it's possible the incompatibility only affects the last shift to the biggest cog? If so, the reports of old 10s RD's working with 11s shifters make sense as many riders have a largest sprocket that's kind of an emergency gear, almost never use it. Maybe the other 10 sprockets shift perfectly. Just a thought, maybe complete bollox!...

Sorry but reality doesn't comport with what you wrote. Reason? Because Campy hasn't changed their 10s shifter pull ratio since 2001 to current day. Consider this. If what you wrote were true and Campy did change their 10s RD from 2011-2014 to agree with 11s geometry, since they didn't change their cassette spacing nor RH shifter detent wheel geometry aka pull ratio, then from 2011 to current day, Campy would have introduced an indexing error into their 10s groupsets and of course they wouldn't do that.

Dave does know his stuff for sure. I believe his testing is accurate. But I don't believe your leap of judgement that Campy changed their 10s rear derailleurs to parallelogram the same as 11s RD's to be accurate. Which comes back to bikerjulio's assessment that 10s and 11s rear derailleurs are identical. And of course Dave's testing on pre 2011 RD's comparing 10s to 11s RD's suggests they do not traverse the same distance with the same shifter which I tend to believe.

[bikerjulio]

'Parallelogram with 11 s geometry'

It would be a mistake to take from this bit of marketingspeak an assumption that the ratio had changed and then follow with a cascade of follow-on assumptions.

Maybe they moved it forward a bit, maybe not. Maybe something else. Does not mean the ratio changed.

Campy have a long history of disingenuous marketing tactics contrived to give the impression that we should pay a lot more for their new or minutely different upper end parts.

I bet it sold a lot of "11-speed" RD's though.

[BigYin]

Sorry but reality doesn't comport with what you wrote. Reason? Because Campy hasn't changed their 10s shifter pull ratio since 2001 to current day. Consider this. If what you wrote were true and Campy did change their 10s RD from 2011-2014 to agree with 11s geometry, since they didn't change their cassette spacing nor RH shifter detent wheel geometry aka pull ratio, then from 2011 to current day, Campy would have introduced an indexing error into their 10s groupsets and of course they wouldn't do that.

Maybe you're right. I'm not sure there is any reason to assume they wouldn't do it though. They've made some odd moves over the years. Even now, 2015 Chorus upwards groups aren't backwards compatible. Crash your shifters now and if you can't find 2014 replacements you'll need a new RD too. Madness IMO. Anyway I digress. If my theory on the RD ratio change was true and only shows itself on the last shift, largest sprocket, then no indexing error would've been introduced for 10s cassettes. Happy to have that theory binned as bollox though, I'm not precious.

Bikerjulio, you're right, I'm making an assumption, maybe wrongly. I'm taking Campag at their word. With the introduction of 'Parallelogram with 11s geometry', coupled with DaveS' documentation of the mismatch between old 10 RD and new 11 shifters, I'm assuming that a real change to RD actuation was made. I think the same change was made to 2011-2014 10s RD. I speculate that Campag have done something quite clever with the change that allows 2011-2014 10s RD's to work perfectly with both new 11 shifters + cassette and old 10 shifters + cassette. Again, happy to be told bollox, but if so I'd be intrigued to know why.

[BigYin]

Just as a wee add on: although I'm generally intrigued and chewing-the-fat with this stuff (it's obviously not that important in the grand scheme), knowing what works does have a practical use, for me at least. I don't have lots of money so I like to be able to make informed decisions on need vs want. I'm converting to 11s, limited budget, if I need a new 11 Rd then my budget says to get Athena. I'd prefer Chorus shifters (this is weighteeenies after all) which I can buy if I do not need a new 11 RD. So knowing this compatibility stuff directly affects my immediate buying decision. Manufacturers of various sorts drive me nuts with lack of clarity provided for us to make informed decisions. Consume consume consume, new new new, money money money...(walks away ranting to himself)

[highdraw]

Just as a wee add on: although I'm generally intrigued and chewing-the-fat with this stuff (it's obviously not that important in the grand scheme), knowing what works does have a practical use, for me at least. I don't have lots of money so I like to be able to make informed decisions on need vs want. I'm converting to 11s, limited budget, if I need a new 11 Rd then my budget says to get Athena. I'd prefer Chorus shifters (this is weighteeenies after all) which I can buy if I do not need a new 11 RD. So knowing this compatibility stuff directly affects my immediate buying decision. Manufacturers of various sorts drive me nuts with lack of clarity provided for us to make informed decisions. Consume consume consume, new new new, money money money...(walks away ranting to himself)

Actually there is much greater nuance. Graeme who is the forum expert on Campy...I know a fair amount....DaveS does...bikerjuilio I find very knowledgable...but Graeme who is a bonefide service shop for Campy has the inside track. Graeme states that Athena rear derailleurs work better with Powershift Athena shifters than say 2011-2014 Chorus/Record Ultrashift because the spring rate in Althena RD's is based upon the lower friction Powershift shifter mechanic. And yet...I just built a bike with 2014 Chorus Ultrashift 11s shifters and Athena 11s short cage 55mm RD it is slams into gear. So much for theory versus practice because in practice 11s Ultrashifters work perfectly with the spring rate used in Athena 11s RD's.

BigYin...only plausible reason for the floated thesis that 2011-2014 Campy 10s and 11s actuation ratios are the same...is that Campy made a companion change to the 10s shifter cable pull ratio by tweaking their internal detent wheel...to fractionally tweak detent spacing affecting cable pull per click. All Campy followers know about the change in the detent wheel and other silent running changes for Ultrashift for model year 2010 because many of us owned the ill fated first year 2009 Ultrashift 10s Centaur shifters which mis-shifted with poor feel and excessive internal cable friction causing poor upshifting down the cassette.

So its feasible that IF Campy did make the RD parallelogram the same between 10s and 11s for 2011-2014 as proposed when Campy cloned the 11s wider RD outboard plate for 10s... that they may of made a companion tweak to the 10s shifter detent wheel...in fact this likely corresponds in fact with when Campy discontinued Ultrashift for 2011 10s and went to Powershift for Veloce and Centaur for 10s and away from Ultrashift...and so this coordinated small change to RD actuation ratio AND shifter cable pull ratio may make sense.

[Valbrona]

I conclude:
-10s RD's up until 2011 are not perfectly compatible with 11s shifters.
-10s RD's from 2011-2014 listed as 'Parallelogram with 11s geometry' are perfectly compatible with 11s shifters.

Depends what you mean by the word 'compatible'.

I believe the design change around 2011 put more tension into the parallelogram spring which may possibly manifest itself as less-than-perfect shifting - for 'perfect' shifting the lever needs to be paired with an RD that it was designed to be used with.

[bikerjulio]

BigYin...only plausible reason for the floated thesis that 2011-2014 Campy 10s and 11s actuation ratios are the same...is that Campy made a companion change to the 10s shifter cable pull ratio by tweaking their internal detent wheel...to fractionally tweak detent spacing affecting cable pull per click. All Campy followers know about the change in the detent wheel and other silent running changes for Ultrashift for model year 2010 because many of us owned the ill fated first year 2009 Ultrashift 10s Centaur shifters which mis-shifted with poor feel and excessive internal cable friction causing poor upshifting down the cassette.

wonderfully geekish thread so far.

I'm going to have to disagree with this theory. And I wrote extensively at the time on my 2009 Centaur shifter experience.

The detent wheel simply spaces the shifts by dividing the wheel up into segments corresponding to whether it was a 10 or 11-speed shifter. It had zero affect on how much cable is pulled per shift - that would be a function of the cable spool diameter.

The issue in 2009 was simply one of weak clicks, nothing to do with indexing which was fine. The improvement kit that Campy put out in early 2010 just firmed up the clicks on those early production shifters as well as fixing the cable interference problem. No change to RD or cable pull.