Noisy XTR M9000 rear derailleur

Nick Payne

I fitted XTR 9000 shifters, RD, cassette and chain to one of my wife's bikes. From the first time she rode it after the new components were fitted, she complained that the drivetrain would intermittently be quite noisy, particularly when climbing hills. I could confirm the noise on the workstand - it sounded as though the RD was sometimes resonating, leading to a buzzing noise as though the jockey wheels weren't properly aligned with the rear cog (they were correctly aligned), and the noise was related to crank speed, becoming more prevalent at a higher cadence and pretty much disappearing at a slow cadence. Engaging the clutch on the derailleur seemed to reduce, but not eliminate, the number of situations when the noise appeared.

After a fair bit of experimentation - replacing jockey pulleys, varying the position of the B screw to place the top pulley nearer or further from the cogs, and swapping the original XTR chain for KMC chain, none of which made any difference, I finally replaced the XTR RD with an XT M8000 when 11-speed XT came on the market. Problem instantly solved! The noise has never appeared with the replacement derailleur.

Anyone else come across such a problem? Have a solution? At the moment I have a rather expensive RD gathering dust...