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Discussion Starter · #1 ·
I have a real simple RD adjustment question that I am struggling on how to describe. I just swapped out my Shimano 105 RD for an Ultegra 6700 RD. I have noticed sometimes that when I shift to a bigger cog on the cassette I get chain rub noise. If I hit the shifter slightly (as if I wanted to shift down to the nest smaller cog) the noise goes away w/o any shifting taking place. Hopefully I described this correctly and a light bulb went off. I experienced this time to time with my 105 RD but am starting to experience this more over the past few weeks with my 6700 RD to the point it is almost coming routine. I assume this is cable tension. Should I tighten or loose the cable with the rear barrel nut? Yes, to answer your question I have never wrenched on my bike until now.
 

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Before doing any adjustments, check your derailleur hanger. You will probably have to take a trip to your LBS and have them put the hanger guage/straightener on it to make sure that its 100% straight.

If its straight, start with limit screws first, then play with the barrel adjusters.
 

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frdfandc said:
Before doing any adjustments, check your derailleur hanger. You will probably have to take a trip to your LBS and have them put the hanger guage/straightener on it to make sure that its 100% straight.

If its straight, start with limit screws first, then play with the barrel adjusters.
If he's able to "trim" it out to make the noise go away, its not a limit screw issue. Plus the OP said shifting onto a bigger cog, not necessarily the Biggest cog - where the limit screw comes into play.

Verify that your RD hangar is straight, then use the barrel adjustment.
 

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OP didn't say why they changed out the RD, either.... An upgrade? Or was the old one damaged? Especially if it was damaged, I agree about having the derailleur hanger alignment checked. It's easy to do, but you can't just eyeball it and need a tool that costs $50+ to check and adjust the hanger. Once set, it usually won't need attention again unless it's tweaked in a fall or something like that. So for most folks it's most cost effective to give a few $ to a local shop to have them check it and adjust if needed.

Also be sure your wheel is fully seated in the drop-outs, not sitting slightly askew (usually this causes other problems, too).

Other stuff...

1. How old is your cable? Did you reuse the existing one? Any corrosion or kink in the cable, or just a lack of lubrication, can cause shifting issues ranging from minor to not-so-minor.

2. When is the last time you cleaned and lubed your chain? That's another seemingly simple thing that often leads to poor shifting. New chain? They come with a preservative on them, aren't actually lubricated, and should be cleaned and oiled carefully before use (I've been using Chain-L lately and really like it). While you're at it, is the cassette clean?

3. Have you put some drops of oil on all the derailleur hinge points? A little lubrication there can often do wonders.

4. Are you cross chaining? I.e., is the noise you hear occuring only when the chain is on the larger chainring up front and the largest cog at the rear? This is a combination that shouldn't be used. Usually when it's done the noises are actually coming from the chain rubbing on the front derailleur cage, but can be mistaken for rear der.

5. I disagree... It could be the H limit screw preventing the chain from seating fully on the cog with a normal shift. Easy to test. Just back the screw out (counterclockwise) a quarter turn or less. If the noise goes away, problem solved. If the noise continues, then it's something else. When installing a different derailleur, both the limit screws need to be set from scratch. Once set up, they seldom go out of adjustment unless something else changes. The limit screws simply do what the name implies... limit the swing of the derailleur to prevent it from moving too far at either extreme, which would move the chain past the most extreme cogs.

6. It might be the B screw needs a little adjustment, particularly with a new installation. This screw is the one that determines the tension in the derailleur, located up by the derailleur hanger and usually unmarked... Since the noise is happening only on the largest cog, it might be set for slightly too much tension. Try backing it out 1/4 to 1/2 turn (counterclockwise) and see if that makes a difference. If not, reset it. Then try 1/4 to 1/2 turn in (clockwise) to increase tension and see if that makes any difference. If not, reset it.

7. After eliminating all the above as possibilities, now it's time to try the barrel adjustment. Lengthening the cable housing (by turning the barrel counterclockwise when viewed from the rear) a click or two will increase the tension on the cable slightly, and might do the trick.

8. Finally, with new parts sometimes it just needs a little while for things to fully mesh and "learn to play together well".
 

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Discussion Starter · #5 ·
To clarify my new RD was an upgrade not somthing I needed to replace because I wrecked. The bike has never been wrecked. It is not the largest cog that I get this problem but mainly shifting to a larger cag from a smaller cog. I haven't noticed it in my largest cog but that would naturally make noise as I get close to cross chaining. I have a 100K ride tomorrow and just cleaned up the bike. I cleaned and lubed the chain and FD & RD. I also tightened my RD 1/4 turn at the barrel adjuster. I should have a pretty good idea if any of this worked after tomorrow.
 

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Brazos said:
To clarify my new RD was an upgrade not somthing I needed to replace because I wrecked. The bike has never been wrecked. It is not the largest cog that I get this problem but mainly shifting to a larger cag from a smaller cog. I haven't noticed it in my largest cog but that would naturally make noise as I get close to cross chaining. I have a 100K ride tomorrow and just cleaned up the bike. I cleaned and lubed the chain and FD & RD. I also tightened my RD 1/4 turn at the barrel adjuster. I should have a pretty good idea if any of this worked after tomorrow.
Okay, you've eliminated a number of possiblities... here's what remains:

1. Barrel adjustment (counterclockwise to increase tension slightly).
2. B-screw adjustment. Effects the spring tension of the derailleur. Turn clockwise a little to incerase tension. If noise goes away, great. If noise increases, try loosening it a little instead. The likelihood of this being a cause is greater because you replaced the RD. It's unlikely the new RD, right out of the box, had this set exactly correctly. If you haven't adjusted it, it probably needs some fine tuning.
3. Corrosion inside the cable housing, if you reused an existing cable. Corrosion comes from riding in the rain, but a fairweather bike that gets regular washings can develop it just as easily. It keeps the cable from moving freely and fully. A good quality, new cable (Dura Ace) solved similar problems I was having with an Ultegra 6600 RD. A kink in the cable or heavy wear inside the cable housing can have similar effect.
4. If on the other hand the cable was newly installed when the RD was installed, then it still could be the problem if there's too tight a radius under the handlebar tape, or even if it somehow got kinked during installation. The quality of a new cable can have a big effect, too. Cheaper, unlined cables are much more likely to give issues.
5. RD hanger alignment... Still a possibility, even tho the bike hasn't been wrecked or anything. Less likely perhaps, but still possible because a lot of RD hangers need alignment on brand new frames right out of the box. If to your knowledge it's never been aligned, it might need doing. The only way to eliminate mis-alignment as a possibility is to have it checked and adjusted as needed.
6. The shift lever itself might have excessive wear. Depends upon how old it is and how hard it's been used. Still, I'd expect this to show up on every shift, and mostly on those gears most frequently used, not intermittently and on less frequently used gears.

Two other thing occur to me. Have you put a drop of oil on each of the pivot points on the RD? And, have you greased the cable guide under the bottom bracket recently?
 

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Hanger check

Amfoto1 said:
RD hanger alignment... Still a possibility, even tho the bike hasn't been wrecked or anything. Less likely perhaps, but still possible because a lot of RD hangers need alignment on brand new frames right out of the box. If to your knowledge it's never been aligned, it might need doing. The only way to eliminate mis-alignment as a possibility is to have it checked and adjusted as needed.
It's also worth noting that you don't have to crash a bike to bend the hanger. Lots of people have bent theirs when the bike just tips over after leaning it up against a store front, or when putting the bike in the back of the car to haul it some place. Aluminum hangers are not that stiff and are pretty easy to bend.
 

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Discussion Starter · #8 ·
The items I listed in my previous post seemed to work. My 70 mile ride yesterday went well with no shifting issues for the most part. I do want to look closer at me DR hanger thought the bike has never been in any circumstance where it would be affected. So if there is an issue it was from the factory. My cables are a little over a year old and came with the bike. My next upgrade are the shifters and possibly brakes and I plan to replace the cables then. For now it appears cleaning, lubing, slightly tightening the barrel adjuster seems to have improved things.
 
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