I'm running a set of Shimano DuraAce 9-speed bar end shifters on my Cross Check. They are mounted on Paul Thumbies. The right shifter is mated with a Shimano LX 9-speed rear derailleur. On certain shifts, the chain rattles just a bit against the next cog. A micro adjustment of the lever within that index position corrects it. This happens with every shift on two cogs: the second smallest and the second largest. I've tried adjusting the rear derailleur several times, but cannot eliminate these rattles, so I think it's an issue with the shifter itself. My questions are:
1. Is there normally a tiny bit of "play" within index positions, or should the shifts be solid every time?
2. If the the shifts should be more accurate, is this a sign of the shift lever beginning to wear?
3. Could the thumbie mounts be responsible? Are shifts less accurate with them than with standard bar end plugs?