Campy Athena front der woes

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Alexandrumarian
Posts: 795
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

And the saga continues:

Sunday went for a ride. All fine (including a fair amount of shifting. except for easiest gear rub) for about 40Km then I do an upshift, chain goes off the big ring and jams between spider and crankarm etc. I untangle it only to see it now refuses to descend on the small ring no matter what. No biggie on the flats, I finish the ride.

Home I take off the derailleur and give it a throughout cleaning. I can't find anything wrong with the pivot points, all tight and smooth. However the cage looks a bit distorted, puffed out. For example outer plate more than 90 deg to the bit that is in the horizontal plane.

I decide the derailleur is damaged after all and since I had in plan to go a fancier group for a long while, order a Chorus mech and SR shifters. From what I've read, Athena 2015 crank should be similar to Record 2014. 2015 Record shifting should work on the crankset, not at its best but should work. (should do until I get money for new crankset and rear mech)

Today i get the stuff, put everything together. First striking thing is the mech sits a lot closer to the frame than the old one. So that one was clearly shot. Did lots of turns on the inner screw to get to 0.5mm between chain and small ring.

Then I pull the cable (new cables and housing) tight by hand, fix the screw. 3 clicks, nothing. Unscrew barrel adjust all the way up, nothing. ?!? Loosen cable, pull it super tight with pliers, now it works (again after opening up barrel all the way). Impressed by shifting, fast and quiet at the derailleur, but ergo clicks very loud and snappy. Nice.

Proceed to tune outer screw. Here it doesn't look so nice. With the screw all-open, I get some rub between chain and that small plastic insert.

Go out for a ride, it works, wait it doesn't work so well. Then it refuses to up on big rig when in middle of cassette. I tighten cable to the max with the barrel, shifter so tight can only do 2 clicks, still not going up. I shift to smallest cog, now it works. Try again to get 3 clicks, now it doesn't work at cassette extremes but works in middle.

Go back home and try hard not to beat myself to death with the bike.

2 possibilities:

-i am a total anti-talent at being a home mechanic
-the chain ring is damaged too. It got bent together with the mech cage during the several times the chain got squeezed out. This happenings were pretty rough as the deep gouges on the spider can attest. Teeth look chewed too here and there...

bcmf
Posts: 129
Joined: Fri May 22, 2009 5:00 pm

by bcmf

So the position of the rear mech is affecting the shifting of the front mech!
This shouldnt happen at all.
Is your frame internal routing?
If so I guess the cables are crossed inside the frame.

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Alexandrumarian
Posts: 795
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

Yes both mechs are internal, but rear cable stayed in place while changing front, and still works as before - i doubt they are crossed inside. I think what happened was chain bend helping the front lift. In the middle, being straight was just at the limit and struggling.

I am as we speak with it on the stand. First thing i detensioned the barrel almost all the way, starting shifting, it just works, and pretty nicely. With less cable tension the clicks are effortless, chain has only some intermittent and minimal hesitations going up. In the morning will go for a spin. If it acts up again i swear i will bite the chain.

bm0p700f
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by bm0p700f

If you have damaged parts replace them. Chains drop it has happened to me in a race once but be more sensitive. With a chain drop I have never managed to damage anything even in a race situation.

Your drivetrain will never work with damaged parts.

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Some points that may not have been mentioned...

I'd check the cable guides. Especially the one under the bb. Check it and see if the cable has dug itself into it. Put a piece of greased liner there.

Also you say the barrel adjusters are all set to their max. Reset the cable and screw it into place. While it is off then set your lower limit screw. (Chain to the left = biggest cog/smallest chainring)

You can't avoid chain rub everywhere. What you want is to be able to shift into the big ring without too much hassle and have no rub in the cogs that are suitable for the chainring the chain is on.

The last thing you should be concerned with is if the big cogs rub on the large chainring or if the smallest cogs rub in the small chainring.

Make sure the cage is parallell to the chainrings. Check your chainrings for straightness. Spin the crank without a chain. If you got bent teeth or rings you can correct to some extent.

Also check your crank for side to side play. This can screw up shifting.

/a

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dj97223
Posts: 822
Joined: Sun Nov 06, 2005 7:27 pm

by dj97223

bm0p700f wrote:If you have damaged parts replace them. Chains drop it has happened to me in a race once but be more sensitive. With a chain drop I have never managed to damage anything even in a race situation.

Your drivetrain will never work with damaged parts.


Agreed. I bought a cheap (but new) 10 speed Veloce f. der recently. I managed a drop/jam the chain and it bent the cage slightly. It was never the same. I don't know if it was the cage or the limit screws were defective, but I could never get it to work right again. I went back to a well-used circa 2006 carbon Record f. der and it has worked perfectly for the past year.
“If you save your breath I feel a man like you can manage it. And if you don't manage it, you'll die. Only slowly, very slowly, old friend.”

Alexandrumarian
Posts: 795
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

Yesterday went out, all pretty decent if not fabulous. Today outagain, horrible. Got home and realized it is actually easy to look inside the downtube as the bottom opening is quite large. Fired a flashlight and guess what...cables were crossed. Bcmf, you have a crate of whateveryoufancy from me!

Now, I imagined redoing it will result in gorgeous operation immediately. To my surprise, it seemed even worse than before. I did it again and again and after a fair bit of sweating it finally seems to be perfect. I think the most important part is to get the cable tension just right when anchoring. Cable should not be slack but not tensioned either. Verify there is not tension in the lever also by pressing the button 100 times. Definite no to pliers. Barrel fully closed, maybe at 1/3. But from there I only had to turn it 1/2 turn max to get really nice upshifts. Fast, quiet, no fuss, no manhandling / prolonged pressure on the lever, no skipping on the ramps/pins - just like it used to be when new. Did a short ride and it seems great. Will see how it goes on Sunday, plan for 100km.

Regarding distorted cages, they can be fixed back some using a smaller C-clamp as a press.

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