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Rear Derailleur Banging on Cogset...
My XT rear derailleur is banging on the cogset whenever I go over bumps. Is this a B-screw adjustment or a chain adjustment (or both)? If anyone knows how to fix this, let me know.
A Shimano derailleur can't really bang against the cogs. Most likely it is banging against the bottom of your chainstay when it swings forward from bouncing across rocks. You can fix it by picking a bigger cog so that it doesn't hit, or by putting some padding (piece of inner tube, etc) on the chainstay or derailleur. Wrapping the whole chainstay with an old inner tube will also help quiet things down when the chain slaps the chainstay.