Bicycle Mechanics - RD Adjustment Suggestions

A little background: The RD, chain, cassette, are new Campy Centaur 10. Wheel is fresh built, and confirmed to be true. I had the LBS put the chain on to the proper length.

I have cabled up the RD, and tried to adjust it. I can set the low and high limit fine, but problems arise in the indexing adjustment. In the middle of the cassette, the chain will run rough in one cog, rubbing the one next to it. One more shift will result in a skipped cog. This would make me think the cable tension is too tight, but if I turn the barrel adjuster to loosen the cable, the RD will not shift from the smallest cog to the next, making me think it's too lose! I can't seem to find a happy place in between. Also, occasionally it will shift ok up through all the gears, but will stumble going back down, or vise-versa. That is to say, it won't run rough in any gear, but it does skip one every time.

I would like to think that all parts are compatible, since I bought this as a kit, but suppose I couldn't rule that out. Though, my left shifter seems to have a few too many clicks for a double chainring...haven't gotten that far yet though.

I have tried to inspect the Der. hanger, but not sure how to verify. I will reply this post with a pic, and see if anyone can help me out.

TIA,

Dax

You didn't mention if the cables were also new. Old cables will sometimes cause your problem. New cables, if all the slack is not removed, will do the same thing. Try loosening the cable nut and pulling all the cable as taught as you can get it without allowing the RD to move. Your problem is almost always cable tension.

THanks for the reply. I have done that several times, and the cables are new. I have taken up as much slack as I can without the derailleur moving. Here are some pics of the hanger, not sure if they will allow any insight, but worth a try.

http://www-personal.engin.umich.edu/~lponced/RD/3.jpg

http://www-personal.engin.umich.edu/~lponced/RD/1.jpg

http://www-personal.engin.umich.edu/~lponced/RD/2.jpg

I can't tell if anything is unusual from the pics.
There should be a cable adjustment on the downtube. When the RD is at those awkward places, use the downtube adjustment instead of the barrell one at the RD. That should give you a little more fine tuning of the cable.

Didn't you get instructions with the parts?That's what I used to set mine up.No problem,other than a little more fine tuning than a shimano 8 or 9 speed setup.Is the rerar casing the right length? and are all the casing cuts square and clean? you did say the rear derailer hanger alignment was ok?

That is a CLEAN cassette! :eek:

The rear derailleur hanger is what I'm not sure about at this point.

I know the mechanics of how to set everything up. Things just don't seem to be working right for me. I have it such that I can shift through all 10 gears (not missing any now!) from smallest tooth to largest tooth smoothly. But, coming back from largest to smallest, I get rubbing from adjacent larger cogs in the last three. Only in that direction though. If I go back the other way, shifts great! Any tweaking of the tension however, causes the chain to slip elsewhere. I think it will come to me eventually, but if anyone has thoughts on how to verify the orientation of the hanger, that would be great!

Thanks,

Dax

In order to check the alignment of the derailleur hanger a derailleur hanger gauge is very helpful. This way one can check the hanger up and down and side to side.

those pics are nice

I suggest screwing the cable adjustment in (or out) a couple of turns before taking up the slack in the cable. The angle at which the cable comes out will have some affect on the way the der moves through its range. This advice isnt based on any great experience, but wont involve any expense and wont do any damage.

That is a good thought.

I actually finally got it shifting pretty well I think. I took it out for a short spin, and it felt like a rocket!!

Then my roommate knocked it over onto the drive side, I got paranoid and messed with it, and it's not moving as well as it was. Still much better though.

What have I heard people say about Campy wearing in? Maybe I just need to give it a chance to break in a little, and ride it around. Just want to make sure I don't wear anything out prematurely.

Building a Campy 10 sp group the first time around was probably a little more challenging than a Shimano Ultegra/105 or something, but man it's beautiful. Is there anything so nice as building your own custom specced bike?

I actually found Campy much easier to assemble than Shimano. The tolerances are much tighter and you don't have that nasty problem of having the cable head slip out of place in the shifters like you do with Shimano.

I would check the derailleur-hanger alignment with a RD-hanger-alignment tool, like Hunter says. The alignment of the hanger is the foundation for all the other adjustments, so it's good to know that it's on target first, then move on to other matters.

Once you're sure the hanger is aligned, and presuming the derailleur isn't damaged so it would sit cocked on a properly-aligned hanger, then you can look at other possible things.

Loose upper-pulley bolt. This isn't very likely but easy to eliminate the possibility.
Shift housing isn't fully seated in the shift lever, and is being prevented from working itself into position by the handlebar tape. Not fun to fix, since you've got to undo the tape if it turns out to be the case.
The ends of the strands in the shift housing are not all the same length. I was in the habit of using a small bench grinder or a Dremel with a cutting wheel, to ensure that the ends of the strands were flat and flush, so they all shared the load. This is REALLY not fun to fix, since there is a good chance that the shift cables will not tolerate being removed and reinstalled. :( (meaning, it's a shame to waste those yummy Campy wires)
The inner wire may have slipped out of the BB cable guide...?
The inner wire may be dragging from a lack of lubrication inside the housings and/or at the BB cable guide. Since the Campy housings may have rubber o-rings in the ferrules, dry cables may encounter significant drag.
Hope some of those brainstorms help.

Let me throw one more notion on the stack: put an allen key into the derailleur's mounting bolt and begin to unthread the derailleur from the frame. Just go about one rotation, while observing to see if the bolt "orbits." If the fall bent the pivot bolt, then it will wobble/orbit as it's unthreaded. If that's the case, you should get a new pivot bolt.