I have an XO drivetrain and have noticed that my bike shifts very harshly when downshifting into my two lowest gears in the rear (biggest cogs) when under pressure. The bike will shift into the gears but will do so very harshly.
I know the last time I had an issue like this with specific cogs it was a matter of the cassette cogs being placed in the wrong orientation when my bike mechanic took off the cassette. For whatever reason the Sram cassette paired with my ZRE hubs allows you to place the cogs on in the wrong orientation (unlike other setups I have had).
so that might be the problem...but honestly I don't know how to tell if the cogs are on right or not.
Mtbr's 2016 Winter Biking GearReviews and Roundups
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