Need help adjusting rear derailleur

For whatever reason the chain won't run smooth on the 27 on the cassette. It runs smooth as silk on every other cog but stumbles a little on the 27. I can't adjust it out for the life of me...any suggestions?

I'm running a 53-39 and a 12-27 (10sp)

It sounds like you need to twiddle the limit screw that limits how far the RD travels in the lowest gear. It's likely the limit screw is not allowing the RD to travel far enough.

Is there ANY possibility that the upper pulley wheel is rubbing against the 27t cog?

If so, then simply remove the rear derailleur from the frame (do NOT remove the cable), adjust the 'B' screw (turn the screw clockwise to achieve more pulley-cog clearance), and re-attach the rear derailleur.

Your the man! Your exactly right. Just looked and sure enough....the upper pully is hitting cogs.

And all this time I was thinking that Alfeng was just being anal about the "B" screw! Great call bro!

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