A couple of weeks ago I got a new frame for my road bike and switched all of the parts from my old frame to the new one. While I was at it, I put on a new chain and cassette. Everything works perfectly except for one thing: I have a mysterious problem with my rear derailleur/cassette/lordknowswhat. These same exact parts were working perfectly on my old frame (except for the new chain and cassette, of course). I am using a 9 speed sram chain with a 9 speed campagnolo cassette (the same combination I've used for several years without a problem).
Here's what's going on: It makes a clicky/grindy sound when I pedal, and the rear shifting is slow and loud. The sound is coming from the area of the cassette, and it is louder and the shifting is slower in the smaller cogs and when I am pedaling hard.
Here's what I have done so far: I have adjusted the derailleur so that it shifted almost perfectly while it was in the stand. On the test ride it shifted poorly. I must have spent 30 minutes riding up and down my street and making small adjustments to try to get it to shift right. Needless to say, the issue persisted. I went down to my LBS to see if they knew what was wrong. They adjusted the derailleur again and had the same issue I had: on the test ride it just wouldn't shift right. Two different people at the shop worked on it. I finally got it adjusted to where it's pretty functional, but its still annoying.
Here's what I'm wondering: could this be a dropout alignment issue? If it is, it is not so misaligned that it's obvious when you look at it. What else could it possibly be?