text: Posted on March 28, 2021 by Tyler Benedict
  XX1 Eagle Derailleur upgrades to a carbon fiber outer pulley cage plate, titanium bolts, and ceramic bearings inside the pulleys. The carbon and titanium save a few grams, but the ceramic bearings are a big upgrade. As you'll see in the video, they spin much more freely, helping reduce drag.
  If you're a set-it-and-forget-it type of rider and want the fastest SRAM drivetrain, this is how you get it. But, for the price differential, it might be worth considering a GX AXS derailleur with something like a Kogel AXS pulley cage upgrade. Conveniently, the price difference between the GX and XX1 is $400…the same as the Kogel upgrade.
  The upgrade kits for all three groups are the same, giving you the derailleur, shifter, battery, charger, and derailleur adjustment tool. The tool lets you easily adjust the B-tension screw to position the upper pulley correction for the best shifting performance.