A Bit Flummoxed By My Campy Chorus 12spd RD

[PsiSquared]

I've never had any issues adjusting an RD before, but I have to admit that my Chorus 12 speed RD has presented a bit of challenge. I can't quite get low gears to shift right while keeping excess noise down. Everything is groovy on the higher end, in fact the top 8 gears sound found and shift fine. The lowest 4 though....not so much. The RD' top pulley certainly looks like it's positioned well.

For reference I'm running an 11-34 cassette with a 50-34 crank. My chain stays are 405mm long center-to-center. Would fiddling with the RD positioning screw again be a possible solution? I think my upper pulley is pretty close to the 11T cog (where I setup the RD position). I don't get any real noise at the end of the cassette.

[oldpotatoe]

Originally Posted by PsiSquared

I've never had any issues adjusting an RD before, but I have to admit that my Chorus 12 speed RD has presented a bit of challenge. I can't quite get low gears to shift right while keeping excess noise down. Everything is groovy on the higher end, in fact the top 8 gears sound found and shift fine. The lowest 4 though....not so much. The RD' top pulley certainly looks like it's positioned well.

For reference I'm running an 11-34 cassette with a 50-34 crank. My chain stays are 405mm long center-to-center. Would fiddling with the RD positioning screw again be a possible solution? I think my upper pulley is pretty close to the 11T cog (where I setup the RD position). I don't get any real noise at the end of the cassette.

Sounds like a der hanger being straight issue to me..That would be the first thing I would check..along with smooth movement of the der cable from outta the lever tto the rear der..

Another small 'gotcha' is ensuring the wee brass washers that the der housing(Cut VERY clean and long enough..si?) pushes against are there and flat.

Another thought..internal der inner wire routing?

[Dave]

RD hanger alignment is the first thing I do with any bike, even a new one.

Campy now has specific chain length requirements for each pair of chain rings and various ranges of chain stay length. Yours should be 55 inches.

When I had chorus 12, I probably didn't pay enough attention to the screw that adjusts the clearance between the upper jockey pulley and largest sprocket. Obviously, there can't be any contact in any gear combination. I had some issues with the 11-12 shift that may have been due to cable friction with my frame's internal cable routing.


https://www.campagnolo.com/US/en/Sup...al_drivetrains

[PsiSquared]

Thanks, all.

The RD hanger is newish, and I checked it for flatness. The bike is a Look 595. I do wonder if the RD hanger is not stiff enough? I don't know what forces or moments the Chorus 12 speed RD exerts on the RD hanger compared to the Record 10 speed RD that used to be there. I wish I could source a Steel or Ti RD hanger to see if that makes a difference.

The cables seem to run freely. The 595 does have some internal routing, but it doesn't doesn't really force any tight bends, especially between the right brighter and the RD. Cables are exterior before entering the down tube just aft of the head tube on either side.

As for flatness, I made double sure to cut my cable housings and dress them so that the cuts were perpendicular to the housing axis and not, uhm, manky.

I am 98% sure that I cut the chain the right length. Is it measure twice and cut once or measure once and cut twice............... I did make sure that I cut the chain the right length as one of the first things I noticed when I did the install was that Campy had a new chain length spec.

Maybe I can convince the wife that flying me and the bike to Vincenza is justified...... I'll bet the folks at Campy HQ could sort things out.


I love everything else about this group: ergos, shift feel...... This RD issues is driving me a bit batty, though. I'm almost to the point of investing in Tune's laser RD alignment tool.

[Dave]

Flatness is not what you needed to check. A hanger alignment tool is needed to be sure the hanger is parallel to the rear wheel. See the park tool website. Get the shifts to larger sprockets working first, then evaluate the shifts to smaller sprockets. If those hesitate, cable friction could be a problem.

[PsiSquared]

Originally Posted by Dave

Flatness is not what you needed to check. A hanger alignment tool is needed to be sure the hanger is parallel to the rear wheel. See the park tool website. Get the shifts to larger sprockets working first, then evaluate the shifts to smaller sprockets. If those hesitate, cable friction could be a problem.

The problem is that I can't really change the alignment even if it is off. I'm not hip to bend the RD hanger, as I'm not sure that's a good idea with this particular aluminum alloy hanger. As for just checking actual RD hanger alignments that was done a few years ago, and it things looked good.

[jimoots]

From the sounds of things - if you haven't already aligned it and it sounds like you haven't aligned it - I'd bet considerable amounts that its the hanger. A Park DAG tool or similar is your friend here.

All my bikes have alloy hangers and I've bent them back with the appropriate tool. If its scary just take it to a shop and they'll have it sorted in a few minutes.

But if you're wrenching your own bikes you should have a DAG and be comfortable using it.

[Mark McM]

Originally Posted by PsiSquared

The problem is that I can't really change the alignment even if it is off. I'm not hip to bend the RD hanger, as I'm not sure that's a good idea with this particular aluminum alloy hanger. As for just checking actual RD hanger alignments that was done a few years ago, and it things looked good.

I agree with the others, the first place to look is the hanger alignment. If the shifting issue is caused by the hanger alignment, there's no magic you can do to fix it other than aligning the hanger. It doesn't take much to knock a hanger out of alignment, so just because it was checked a few years ago, it doesn't mean its still in alignment today. Aluminum hangers don't take as well to being bent multiple times like steel hangers do, but they can still take a fair amount of one-time bending. It sounds like the hanger is replaceable, so you have little to loose if it does need to be bent back into alignment.

[parallelfish]

Replaceable hanger:

https://wheelsmfg.com/derailleur-han...anger-134.html

Also, ensure that the RD “joint”, which attaches to hanger, engages the tooth on the hanger. Easy to miss this.

[Wakatel_Luum]

Originally Posted by PsiSquared

I've never had any issues adjusting an RD before, but I have to admit that my Chorus 12 speed RD has presented a bit of challenge. I can't quite get low gears to shift right while keeping excess noise down. Everything is groovy on the higher end, in fact the top 8 gears sound found and shift fine. The lowest 4 though....not so much. The RD' top pulley certainly looks like it's positioned well.

For reference I'm running an 11-34 cassette with a 50-34 crank. My chain stays are 405mm long center-to-center. Would fiddling with the RD positioning screw again be a possible solution? I think my upper pulley is pretty close to the 11T cog (where I setup the RD position). I don't get any real noise at the end of the cassette.

I had the exact same issue when I installed 12 spd Chorus from 10 spd Record, no matter what I did I could only get one half of the cassette to run quiet. I think the newer system is quite finicky and sensitive. Instead of a 1 & 1/2 turn on the derailleur barrel adjuster as on my 10spd, the 12spd only requires a half turn. I just kept chipping away at the adjustments and eventually got there. I think also I went to a wet lubricant too from a wax lubricant which was binding up my jockey wheels causing resistance.

I had the same issue with 12 spd Record on m other bike which I just took to a bike shop and they got it right away.

I'm an okay mechanic on most bike components but derailleurs always give me a hassle.

[PsiSquared]

Originally Posted by Dave

Flatness is not what you needed to check. A hanger alignment tool is needed to be sure the hanger is parallel to the rear wheel. See the park tool website. Get the shifts to larger sprockets working first, then evaluate the shifts to smaller sprockets. If those hesitate, cable friction could be a problem.

Alright. I'm convinced and ordered a Park DAG-3 hanger alignment tool.

[flying]

Originally Posted by Dave

Get the shifts to larger sprockets working first, then evaluate the shifts to smaller sprockets. If those hesitate, cable friction could be a problem.

^^^double check this^^^
It is funny but with Campy even if you just have the cable into the exit of the RD a little off (meaning not straight) it will cause symptoms like your having

Which is basically a cable friction prob

I also had a similar prob & thought it might be hanger alignment which it wasn't

[DfCas]

It is also possible to anchor the cable at the wrong place. The "washer" that has 2 legs and a slot for the cable can be turned to the wrong position under the 5mm cable anchor bolt. I did this due to my poor vision and poor lighting conditions. It was OK across 7 or 8 gears and then the error added up to too much for the last 4-5 gears. This caused the wrong amount of derailleur travel for each shift.

[flying]

Originally Posted by DfCas

It is also possible to anchor the cable at the wrong place. The "washer" that has 2 legs and a slot for the cable can be turned to the wrong position under the 5mm cable anchor bolt. I did this due to my poor vision and poor lighting conditions. It was OK across 7 or 8 gears and then the error added up to too much for the last 4-5 gears. This caused the wrong amount of derailleur travel for each shift.

You explained that much better than I did

I believe I somehow did the same & had the same problem

[PsiSquared]

Thanks, all.

The DAG-3 revealed the RD hanger needed some tweaking. Some tweaking was done, and gaps are down to less than 2mm at the worst, which means that the RD is aligned to within less than 0.4° all the way around.

The RD is much happier now.

I should have bought derailleur hanger alignment tool a long time ago.