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Can anyone tell me the proper chain length for Campy gear? Using an Ultra (narrow) chain currently which is very noisy in the extreme/end gears. And yes, I know that you're not really supposed to use these gears. However, while at the bike shop they suggested I use another couple of links in the chain which I did. The noise is still excessive. I'm not trying to get this totally quiet. While the chain is pretty new (less than 300 miles) the sprocket and cassette have about 1,500 miles on them.

On the campy site, they suggest 10 to 15 mm gaps on the rear derailleur while on the smallest gear/crank but that's where I was before the bike store said I should add a couple of links.

Then again, Am I asking too much for the first two gears and the last 3 gears to be relatively quiet ?
 

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Two methods

First, there is no such thing as the "right length." Different combinations of cog and chainwheel sizes and different chain stay lengths affect chain length. The two standard methods for determinining chain length are to put the chain in the small-small combination and shorten it until it just "activates" the rear derailleur cage - at this point you would have just removed any slack in the chain. The other procedure is to put the chain in the large-large combination and add one inch (two links) beyond what is needed. In many cases, these two methods will give you the same chain length, but that will depend on all of the variables mentioned above.

Regarding your drivetrain noise, you should do a careful inspection of the system while it is in the noisy gears. Once you determine what is causing the noise, then you can address the problem. It may not have anything to do with chain length.
 

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the whole long story...

There really is one length that is correct, if you don;t have some sort of odd setup that exceeds the RD wrap capacity. Chain length can't be your problem if you have noise is the smallest and largest cogs. You do know not to use the big ring and largest cog or the inner ring and smallest cog? The chainline is too extreme. Here's the lengthy version.


Two simple tests will determine if the chain is the correct length. First, it must not hang loose in the little ring, little cog combination. If there is no tension on the chain in the little ring, little cog combination; remove two links (one inch) at a time, until there is. When the ends of the chain are brought together, some movement of the lower pulley should occur, indicating tension is being applied. Two more links (another inch) may need to be removed, beyond the point of absolute minimum tension, to keep the chain from rubbing on itself or the chain guide tab as it passes under the upper derailleur pulley. If you want to see how much lower pulley movement will occur, without removing the extra inch of chain, shift up four teeth (11 to 15 or 12 to 16). This has the same effect as removing two links. Once this is done, the chain is set to the maximum useable length. Removing additional links will do nothing but reduce the derailleur's capacity.

Second, the chain must be long enough to avoid over-extending the rear derailleur when shifted to the big ring and biggest cog combination. If the chain is set to the maximum length as described, it should always pass this test, unless your setup exceeds the derailleur's stated wrap capacity. If you deliberately exceed the derailleur's capacity and the derailleur is over-extended in the big ring/largest cog combo, then you must either avoid that combo or add another inch and avoid using the little chainring and the smallest 3 or 4 cogs (since the chain will hang loose).
 

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Quick method I've used for years...

There are probably many theoretical reasons this isn't ideal, but I've used it for years on all kinds of drivelines, and it's always worked for me: Run the chain through the derailleurs and over the large chainring and biggest sprocket, then add two links. It insures you won't break anything if you accidentally go across the driveline, and there's usually enough take-up in the rear d. to handle the slack.
What I wonder about is your insistence on using the gear combinations that cause the trouble. There are duplicates for those gears that are easier on the driveline; why not use them?
 

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why it's not ideal...

The method you described will work, but it sets the length based on the largest cog being used. If the cassette is later changed to a larger cog, then the chain may be too short. The little/little method insures the maximum chain length that will handle any cassette in the RDs wrap capacity. A shorter chain is not of any benefit.
 

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And furthermore

C-40 said:
A shorter chain is not of any benefit.
This comment reminds me of the mechanic's mantra from back in the day: for minimum drivetran friction the chain should be nearly hanging loose in your small-small combination. This further reinforces using the small-small combo to size the chain.
 
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