Campag Chorus Front Mech

[colley340]

Being suffering from a noisy drive train for a while so decided to go through everything to check alignment / settings.

I messed around for around an hour today trying to get the front mech lined up correctly but I'm not convinced its right. What i did:

1) Used the campagnolo deraileur alignment tool to ensure tooth gap was 1-3mm and front plate parallel with chain ring. Seems perfect.
2) Set the inner limit to ensure 0.5mm gap in small ring (front) and biggest ring at the back (no cable tension). No chain rub on inboard mech plate.
3) Set cable tension with inline adjuster set mid position so i have some +/- range.
4) Shifted to the bring ring and set outer limit so the chain didnt get thrown off. Seemed to shift nice on the lever.
5) In the big ring shifted to lower cog at the back and had chain rub on the front mech outer plate.
6) Adjusted cable tension (increased) to push front mech outboard giving a small gap and no chain rub.
7) When shifting back to small ring (front) and large ring at the back have inboard chain rub,

No matter what i did i couldnt get them both perfect? Given the fact there are no more degrees of freedom im stumped as to how i can improve it.

Additionally, in the most extreme cross chains angles possible i have a lot of plate rub until i shift 2 cogs towards the centre. Is this normal?

Can anyone help?

Thanks

[Calnago]

Sure. But for sake of this post I’m going to have to make some assumptions about information you didn’t provide... first, I’m assuming this is 11sp, post 2015 but not 12sp, right? Also non disc, so not H11. And finally, not overly short chainstays.
First let’s undo a couple things you did to get you to a decent start over point...

1. Back off the high limit screw, like way off. So that you could throw the chain off the outside in the third click if you tried. There is some overrun in the third click that you need to have free for now.

2. Turn the inline adjuster more to the fully closed (least tension) for now as you will want some room to tension things up later.

3. Back off the low limit screw for now, but you’re probably fine if you have 0.5mm clearance already (with chain on small ring and large sprocket).

4. Maybe snug up the cable a bit If it became loose when you backed off the tension using the inline cable adjuster. Just get the slack out if the cable for now. You’ll be doing the final tensioning with the inline adjuster when the chain is on the big chainring. Make sure the cable is around 0.5mm from the chain, while on the small ring and large sprocket, without the help of the low limit screw, or if you need the help of the low limit screw a bit, that’s fine, but if the initial cable tension is way too loose you may not be able to get enough tension on it with the inline adjuster later on.

5. Ok, push through 3clicks so that the chain is now on the big ring. Should have gotten there fairly easy, and since the high limit screw is backed off, it may have even wanted to get thrown off the outside, Don’t worry about the upper limit screw just yet. The derailleur needs to be able to do its over run and settle on the large chainring, at least that’s where it should be now. If the upper limit screw is interfering with the overrun at this stage it will make it next to impossible to dial in correctly. If it didn’t make it there in 3 clicks, then your cable tension to begin with was too low (or the upper limit screw is preventing it from doing so).

6. Ok, now you’re at the most critical part of the adjustment. With the chain on the big chain ring and largest sprocket (cross chained), use the inline cable adjuster to move the front derailleur outward so that the gap between the chain and the inner plate is as small as possible without rubbing (0.5mm or less).

7. Ok, at this point you should be able to shift to all cogs cleanly while on the big ring without the chain rubbing on the derailleur in any of the combos.

8. Ok, shift the front back down to the small ring by pushing the thumb button all the way through to the stop. There will be one (somewhat confusing) click on the way which I call no mans land. Ignore it, push all the way through to the stop. One more click after being released at the stop and it should be at the innermost point. Double check to make sure the inner plate isn’t rubbing on the chain when it’s on the largest cog and small chain ring. If it’s all good, you can set the lower limit screw at this point.

9. Ok, shift the front derailleur one click out. Shift the rear derailleur to somewhere in the midland part of the cassette, maybe the 4th smallest cog.

10. Click the front derailleur once more outwards. It shouldn’t be on the big ring yet, but you should be able to completely cross chain small/small with no chain rub on the derailleur.

11. Ok, one more click should get the chain to the big ring. Don’t overthrow it as the upper limit screw still isn’t set. Make sure you can still run through all the rear cogs at this point with no front derailleur rub anywhere. (Remember, I’m assuming you’re on 11sp. 12sp operates a bit differently).

12. If all seems ok then basically you just have to set the upper limit screw now. So, with the chain on the big ring and smallest sprocket, make sure there is daylight between the chain and the outer plate of the front derailleur. Turn the high limit screw in a bit till it just touches the front derailleur stop, then back it off a smidge (you will want it to have some overrun room but not so much that it gets overthrown or so little that you can’t get the third click or is difficult to get the chain onto the big ring). At this point it’s kind of trial and error process to set the upper limit screw just right so that you can aggressively shift from the small ring to the big ring without it overthrowing but still gets up there easily, achieving the third click with a bit of overrun, regardless of which cog the chain is on at the back. Once set up, you should be able hit cleanly any cog while in the big chainring without touching the front derailleur until you want to drop it down to small ring again.

Ok, that’s it for your 12 step program this evening. Hope it helps a bit. I’m not proof reading this now as I wrote it while my friend went to the rest room. Lol

[robertbb]

Your friend needs some probiotic if he/she was in there long enough to write this.

[Calnago]

[colley340]

@Calnago - thanks for such a detailed response, most appreciated.

[CLEAR]

lol

Your friend needs some probiotic if he/she was in there long enough to write this.

[Calnago]

@Calnago - thanks for such a detailed response, most appreciated.

Not a worry, what else was I supposed to do during “the break”. Did you get it sorted? And were my assumptions on your group being post 2015, 11sp, and non disc correct?

[colley340]

@Calnago - thanks for such a detailed response, most appreciated.

Not a worry, what else was I supposed to do during “the break”. Did you get it sorted? And were my assumptions on your group being post 2015, 11sp, and non disc correct?

Hi Calnago,

Yes it was an 11s non disc, i managed to get it set up quite well following your instructions but could not get rid of a very slight chain rub in the big ring / big sprocket. The second i shifted down at the rear the rub went away so considering that i'll never use that gear i think ill leave it. My chain stays are quite short and possibly some manufacturing error on the Ti frame?

Im now moving to the rear and followed an Arts cycling video on youtube but struggling to fine tune it. Do you have any tips for the rear? Ive set the pulley wheel close to centre of the first sproket and adjusted the limit screw to a point where it seems the quietest. I then set the cable tension and started to move up, checking the alignment at 4th gear by eye/ear.

Should the inboard limit screw by backed out when fine tuning the cable tension? This seems to be affecting the shifting. Ive checked the distance of the pulley wheel is correct as per Campags spec using the B screw.

Thanks

[jih]

You say you're strugling to fine-tune the rear but what actual problem do you have that needs correcting? Is it skipping, noisy etc?

Often if the rear can't be made to work nicely, the best first check is the rear mech hanger alignment.

[colley340]

You say you're strugling to fine-tune the rear but what actual problem do you have that needs correcting? Is it skipping, noisy etc?

Often if the rear can't be made to work nicely, the best first check is the rear mech hanger alignment.

Been having all kinds of noises but not sure what is what. I wanted to go through everything to check its setup right before replacing anything (chain is close to needing to be changed). Im no longer having noise coming from the front which must have previously been the front mech plate rubbing. I now want to get some swiss watch precision at the rear. Yes the hanger has been checked previously and ive had no crashes since it was checked.

Thanks

[DaveS]

You're not supposed to use the big/big. I don't use the two largest sprockets with the big ring.

[DaveS]

You're not supposed to use the big/big. I don't use the two largest sprockets with the big ring.

[Attermann]

You're not supposed to use the big/big. I don't use the two largest sprockets with the big ring.

Off course you are supposed to use them too.