I've had index shifting problems ever since I've had this bike. I got a Park DAG-2 a while back, adjusted everything seemingly perfect, and shifting got better but still not reliable enough to use indexing (friction works fine).
The symptom I have is seemingly perfect indexing 90% of the time, then sudden "pop" noises of the chain not being properly aligned with the cogs.....then a long time with nothing, then it happens again, etc. I've tried several different chains and cassettes -- same problem.
I looked at the hanger upside down and can clearly see that the derailleur and hanger don't appear to be parallel.
Is this normal? I double checked and the 4 cardinal directions lined up with the tire valve are within 2 mm of each other (perfect - according to the tool).
Should I trust my instinct and make the hanger look more parallel even though the tool says otherwise?