SRAM XX1 Eagle Rear Derailleur - 12 Speed, Lunar Max 52T 520% RangeSRAM Eagle just got a little better now with extended range! If Eagle just isn't enough for you they've now added 2 teeth to the cassette! If you need a little extra help on the climbs but don't want to sacrifice your top speed by dropping the front ring this is just what you need! Upgrading or setting up a 10 52 Eagle drivetrain? You will need a new derailleur since the added range is just a little too much for the 10 52 derailluers. That means if