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PostPosted: Thu Aug 08, 2013 8:33 pm 
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How about fitting the RD on another frame to see if that works okay elsewhere.

Swapping out the ergos will be more of a faff & I'd always try & go for the easier wins first.

Maybe next on the list after the RD could be a whole different wheel & cassette ?


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PostPosted: Fri Aug 09, 2013 6:38 pm 
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Chain length?


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Posted: Fri Aug 09, 2013 6:38 pm 


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PostPosted: Fri Aug 09, 2013 7:09 pm 
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Crossed cables was going to be my suggestion as well but you seem confident you've ruled that out. I diagnosed this particular problem on a bike recently when I realised I could see the rear mech moving a tiny bit as I shifted the front.

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PostPosted: Fri Aug 09, 2013 7:36 pm 
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Gave it a rest today, we're going to try a fresh cassette and rd along with a friction test on the cable as the next step. Though tbh, I'm not convinced they will bring improved results as I still cant see how they'd change function when in different rings :/

Couple of things have got me thinking though....
Rear housing section length -have tried both the pre-cut campy one that comes with the cables and a slightly longer gore sealed one, perhaps the change in rd angle is causing enough movement of this section to alter cable tension slightly?
Hanger alignment -I'm using a Park tool that is around 6 months old, there is a tiny amount of play when measured at the rim (maybe 1-2mm) however no other groupset has exhibited a problem when set with this tool, so maybe record/super record is way more sensitive to tiny mis-alignments?


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PostPosted: Fri Aug 09, 2013 8:38 pm 
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I'm not buying the "11-speed more sensitive" line that keeps cropping up. (not getting at you, OP) It's just not so. Yes, the cogs are a little closer - but the chain is narrower too. I found absolutely no different than setting up 10-speed. (it is a 5.5mm 11 spd chain, right?). In fact it was if anything quicker, and resulted in the quietest drivetrains I have ever (not) heard. My BMC has a non-alignable carbon hanger and it's been fine.

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PostPosted: Fri Aug 09, 2013 8:51 pm 
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I wouldn't pay heed to that either, had no such issues with chorus and athena 11 (or dura ace 11spd for that matter). But I would say that record/super record do appear to be more sensitive to problems which I would assume is due to finer tolerances on the parts vs their cheaper stable mates.


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PostPosted: Fri Aug 09, 2013 9:26 pm 
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bmxbandit wrote:
I wouldn't pay heed to that either, had no such issues with chorus and athena 11 (or dura ace 11spd for that matter). But I would say that record/super record do appear to be more sensitive to problems which I would assume is due to finer tolerances on the parts vs their cheaper stable mates.


Naah. Sorry, but it looks like you drank the koolade. Campy are masters of "badge engineering" there's no difference at all between Chorus and Record or SR for that matter in the internal mechanisms - meaning shifters and RD. It's just some cosmetics and a lot of hype. Check out the spares catalog if you don't believe me. Different levers and finishes and logos account for any p/n differences + the odd Ti screw on SR.

http://www.campagnolo.com/repository/documenti/en/SPARES2013-PART_A-27-11-12.pdf

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There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


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PostPosted: Fri Aug 09, 2013 9:27 pm 
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bikerjulio wrote:

I have always run cables at the front with no problem.

Every pro installation I have seen shows cables at the front.


...and I have seen plenty pro bikes run cables through the back as well. Either way works but what is correct and optimal is more a function of type of bars being used. If the bend from tops to ramps is tight (e.g. Easton EC90 SLX3) then you will want to avoid running der cables in front because the bend is nearly a right angle bend and much too tight (yielding increased cable friction). If the bend from tops to ramps is a gradual bend (e.g. Deda shallow or deep drop) then running cables on inside will work fine. However when cable friction becomes an issue then cables should be run through back, regardless of bar geometry . Specifically, when mounting cables on back of bars the der cable will follow a straight line when it exists the lever and threads through the ergolever cable guide, as opposed to being forced to make a tight bend needed for the front mounted cables. This is a critical point of friction and if poor shifting linked to cable friction is an issue then this is the most important point where you can avoid friction.


bikerjulio wrote:
Campy promo videos for the shifters show cables at the front.

Campy now supply shifters with DR cables pre-installed and in the front position!


Just because they are pre-threaded in that position that doesn't mean that is the optimal installation (see above). I suspect they might pre-thread the cable to simplify packing (it is easier to bind and pack two cables together when they exit the lever as opposed to being separated by about 2 cm)?



To OP, looks like you might not have addressed the chain length issue yet? Also, what hanger are you using? In my experience stock hangers from some manufacturers are cheap stamped alum rather then machined ...this makes a huge differences in shifting. I exchange all my hangers with Wheels Manufacturing hangers which are both machined and consistently beefier (literally more material) then stock hangers. As has already been noted, proper length of rear der cable loop can also make a difference. Lastly, I would avoid the Gore cables all together...they might be slick upon installation but after just a bit of use the cable coating begins to wear and gunk up inside the housing. I have had better luck using Shimano der housing with Campy cables (the only Shimano product that touches my bike)...the Shimano housing has a slightly larger liner diameter and yields less friction all together (this was per recommendation from DaveS...who interestingly has yet to weigh in on this thread?). See pic below illustrating rear der cable loop and chain length...EM3

Image

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PostPosted: Fri Aug 09, 2013 9:59 pm 
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@ bikerjulio, not sure what you mean by 'drank the kool aid', I'm pretty much clutching at straws trying to find a reason for this issue. Though I would definitely say athena has a noticeably different feel to chorus and record/sr. Just because the internals are the same does not mean the other parts of the construction may make them more or less sensitive to 'perfect' set up conditions.

@ em3, thanks for the input, chain length is bang on as per the small/small method so fairly sure it's not that. Initially the stock hanger was used, second one was a wmfg one, so both bases covered there. Interesting point on gore cables, we have several staff bikes running through british winters with no issues thus far, but like I said earlier we have tried several cable combos. Next check will be a friction test to eliminate this 100%. Interstingly, the tech guy at one of the UK campy agents told me to not use shimano housing because it had a different compression ratio than campy housing :)


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PostPosted: Fri Aug 09, 2013 10:08 pm 
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My 2 setups shown for info. One Chorus and one Athena. Both Campy std RD housing. Both in the Big-small combo. Both KMC SL chain. Both housings routed to the front of the bars. Easton EC90 Equipe Pro in one case and Ritchey WCS ergo in the other. Both shifting perfectly and super quiet.

Image

Image

Image

Image

ps just saw your post. Chorus, Record and SR shifters and RD's are virtually identical. No functional difference at all. Athena IS a different internal mech, a form of what is known as "escape", function is quite different and similar to the 10-speed Centaur and Veloce mechanisms.

If you are not familiar with the expression, it was used here in the sense of believing that SR is more finely made because it's more expensive. http://www.urbandictionary.com/define.php?term=drink+the+kool-aid

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


Last edited by bikerjulio on Sat Aug 10, 2013 1:21 pm, edited 1 time in total.

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PostPosted: Fri Aug 09, 2013 10:32 pm 
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OP getting back to my original suspicion - that it's related to excessive cable friction - there have been other similar problems reported with frames having internally routed cables. I'd suggest an easy test. Remove the cable from the RD, remove the last bit of housing, push the cable end back out of the lever so that you can grab the end. Now you can run the cable back and forth through nearly the whole system. Anything more than a couple of pounds worth of friction is too much, and the less the better obviously. And just for fun, do this with the FD in both positions.

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


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PostPosted: Fri Aug 09, 2013 10:46 pm 
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^ thanks for the pics guys, you both appear to be using a longer piece of rear housing than what we have tried (including the pre-cut campy one). What I was getting at with the comment on record/sr being more sensitive was the different construction yielding parts that require a near perfect 'operating condition' -this could be said of many high end/exotica parts/frames/wheels, where cheaper parts tend to have more tolerance for less ideal 'operating conditions'.

As for cable friction, we have tried the more 'agricultural' methods of checking cable friction that would normally do the trick for diagnosis of cable issues. At the next opportunity we'll be trying a more scientific approach of a measured weight versus the listed spring weight of the rd for a definitive answer on the cable front.


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PostPosted: Fri Aug 09, 2013 10:56 pm 
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Small, Small chain length? I've always used smallest in the back (11 or 12 tooth) big ring in the front and the derailleur is at a 90 degree angle with the ground. That having been said. If chain length was an issue, it would still work in most gears across the board. Even a chain that's too short will still work well in 53x 11, 12, 13 and 14. You wouldn't get major issues until you got into the larger sprockets. And too long would work fine in say 39x25 or 27 down to a 19ish. But be too slack below that. This is all roughly speaking and dependant on how long or short it is. But if it doesn't work at all in the big ring and does in the small and works in the big ring but not at all in the small, chain length isn't likely your issue. And yes,, I'm aware that someone else will follow up shortly telling me I'm wrong because their sister's cousin's brother's mother has proof otherwise, but I think you get what I'm saying.lol
I think the best advice you've been given thus far is to try parts you know work, starting from back to front until you have it right. Refresh my memory. Campy cranks,, or other?


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PostPosted: Fri Aug 09, 2013 11:42 pm 
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Small/small = chain as long as possible without fouling the upper pulley/cage when in small rear cog/inner ring combo with upper pulley to large cassette cog distance correctly set. Given compatible parts this method has always yielded best results for me over any other chain length calculation. I'm aware differing chain length can be advantageous in certain conditions, I'm fairly sure the way I've set it here is spot on.


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Posted: Fri Aug 09, 2013 11:42 pm 


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PostPosted: Sat Aug 10, 2013 12:00 am 
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Thanks. I'll have to try this sometime. It's always good to know different ways to do things. If it works better than my method, it might just stick.


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