I did a search but could not find the answer. I have a 2008 Trek Madone 6.9 with full Dura Ace 7800 group set. Double crankset and 10 speed (11-23) cassette. On the three middle cogs, every other tooth, it grabs the chain as it exits the cog. I can still ride the bike and the chain still runs fairly smooth, there's just an annoying clicking noise. I had an Ultegra (12-27) cassette before with no problems until I switched it out last night with the Dura Ace cassette. I dialed in the rear derailleur (limits, tension, barrel adjustments, etc.) but I have yet touch the B-tension screw. I will try that tonight. Anything else you guys think that can be the cause of that "grabbing" click noise.