rear loop length?
 

I will ask my fellow mechanics about rear derailleur set up. I know there is a fine line with the rear loop on the length and precise shifting. If it is too tight it generally will cause more problems than too big a loop. I not sure if the loop should go all the way around the quick release but my set up seems to have the line of the loop going right over the QR. I personally think the biggest rear loop you can get that is smooth is the best, do any of you subscribe to this?


The reason I ask is I am very OCD about shifting and hate to miss any shifts period. I find the going to the bigger cogs in the rear never a problem but if I get it too tight then it does not always upshift perfect. Turn the cable adjuster just a 1/4 turn will usually get it perfect.


Finally, on my Wilier I am running 10 spd Ultegra and about a year ago upgrade and got the Shimano Polymer Coated cables and housing. I put those on and in the 4000 miles since then they have shifter perfect never a missed shift. I wonder if maybe going to these exclusively is the way to go. This has the cables buried in the tubes and is much more susceptible to problems and the new shimano polymer stuff has taken care of that issue.


How do you run your rear derailleur loops?

SIS Housing is stiff so go Long smooth curve for lower Friction

I put a [oldAvid]rollamajig like thing in to let the housing be even straighter in ..

When I recently changed out the shift wire for my 6700 RD, there was an obviously worn/shinier section on the wire about 1" long right in the middle of the loop of cable that enters the RD. So I took that opportunity to replace the cable with one about 2" longer, and shifting improved immediately-- I would occasionally have the issue where the RD didn't want to go into the smallest cog. That's gone now. So for sure, better too long than too short.

Most bikes have a significantly too short housing length on the rear loop. Longer with a smoother bend is better. I've seen lengths so short the strain from the sharp bend eventually cracks the ferrule.

I set up the housing loop length so that the housing enters the derailleur socket straight when the derailleur is in the middle of its travel. I take Sheldon Brown's advice and bend the loop to its approximate shape before cutting it so sittays square: Cables If you cut the housing and then bend it, the end will take a slanted shape which will not seat evenly.

http://www.parktool.com/assets/img/r...Figure_9-9.jpg
Cutting and Sizing Cable Housing | Park Tool

The segmented Nokon housing may function better with shorter sections..

NokonUSA Home

excessively short will also cause ghost-shifting under load and rear triangle flex - and it will shift to a smaller cog which makes climbing even tougher.

330mm / 13" which is the Campagnolo standard.