I have a felt Ar4 2009. It runs full ultegra SL double 53-39 with an 11-25 in rear. Chain was recently replaced. It was pretty past due when I replaced it. However with the new 6700 chain on there is no skip while riding. However, I have noticed recently that the shifting appears to be quite loud and rough in the rear and I cannot get it to quiet down through adjustment of cable tension. I have tried adjusting the B screw but this doesn't seem to make much difference. When i replaced the chain a couple hundred miles ago I also overhauled the rear derailleur pulleys and thoroughly cleaned and lubricated the rear derailleur. I also aligned the rear derailleur hanger however, it could be slightly out of adjustment at this point. I keep the drivetrain running extremely clean. There is no measurable stretch in the chain at this point. Shifting to a larger gear in the rear is quiet and smooth. The bike seems to respond well when asked to shift. Shifting is immediate with no hesitation in both directions. However when i try to upshift into a smaller cog it is very loud and rough. I thought maybe my cassette teeth could be getting worn so i tried swapping the cassette with the cassette on my cross bike which has far fewer miles but I saw no difference, if anything it was louder.

Wondering if anyone could throw in their 2 cents toward what's going on here?

- Rufio

let's see- rough shifting can be from cable issues, chain/cog ones or der alignments. You've said that der alignment is not wrong. You've replaced the chain, maybe later in it's wear cycle then best. So this might be a possible contribution, the miss match of wear between the chain and cogs. But this usually is experienced as a skip or excessive noise after the shift is acomplished. Not during. So next is the cable, you haven't mentioned this yet. Cable friction will inhibit the der from tracking the commands from the lever often. More so if the cable has grime, corrosion or is internally routed.

I'll disconnect the cable (from the frame stop or the anchor bolt) and run the der through it's range by hand. If all moves smoothly then i'll pull the cable while i run through the lever's clicks. An experienced hand can feel some problems. I'll make sure the cable and casing is not worn, frayed or pulling through the casing end caps. I'll lube the cable/casing along it's full run. Along with this I'll also make sure there're no bad links or teeth. usually along this path I'll find something below spec or worn.

Most issues of shifting that creep into a system are from lack of maintance or not replacing all the interfacing parts when worn. Andy.

Just "adjusting" the "B" screw may be your problem. I know on my Sram 7 RD there is a specific adjustment recommended. It is 6mm between the jockey wheel and the the largest cog. I would suggest you find out what Ultegra spec is and adj accordingly. My Sram RD shifts are almost noiseless 95% of the time.