Bikes and Tech
SRAM's new XX1 Eagle drivetrain goes big with a...

A 12-speed cassette? SRAM announces Eagle

Need an easier gear? SRAM's 12-speed (yep, 12) MTB group offers a gigantic 50-tooth large cog, paired with a single front chainring.

SRAM is going big — really big — with its new Eagle technology that will apply to updated X01 and XX1 drivetrains. The new 1×12 drivetrain system features a massive 50-tooth cog on the 10-50 X-Dome Eagle cassette (XX1 group). And while that’s the most noticeable difference in the new drivetrain, it’s not the only trick up SRAM’s sleeve.

Because of the larger cog on the cassette, the rear derailleur was redesigned to handle the capacity. Both the XX1 (261 grams) and X01 (276 grams) derailleurs feature a 14-tooth lower pulley that SRAM says will shift smoother and be quieter. The Cage Lock has been relocated as well to prevent damage during riding. SRAM has also redesigned the Type-3 Roller Bearing Clutch that has a smoother torque curve, which should improve shifting.

SRAM has made a big deal about the demise of front derailleurs, and as such, redesigned its crankset. Both the XX1 and X01 Eagle versions feature carbon crank arms mated to direct-mount chainrings. Those chainrings are specific to Eagle drivetrains; SRAM says the new X-Sync 2 chainrings provide quieter operation and better mud-clearing. Chainrings are available in 30-, 32-, 34-, 36-, and 38-tooth iterations.

Such a wide gear range is likely to put a lot of stress on the chain, which is why SRAM redesigned that, too. Both the XX1 and X01 Eagle chains eliminate all sharp edges and chamfers to reduce wear. The outer plates are flatter, which SRAM says ups the strength and longevity thanks in part to better chain riveting. This design, which SRAM calls Flowlink, allows for a narrow chain that can withstand sharp chainline angles.

Trigger shifters have updated internals, SRAM’s MatchMaker X, and adjustable thumb-button position. The GripShift shifters have also been updated, and SRAM says shifts are smoother and the unit is more durable.

Interestingly, SRAM has not addressed the most significant drawback to its single-ring groups: large jumps between cogs. With this 12-speed cluster, the jump from 24T to 28T, for example, is a significant cadence change.

The other question is, of course, do we need a 50-tooth cog? Or was 42 teeth good enough? Regardless of your area’s terrain, Eagle has landed and looks like a viable option — a 50-tooth cog might just be what some riders need to muscle up those steep mountain climbs.

Eagle prices and weights

XX1
Total group:$1,417; 1456 grams (not including BB)
Crankset: $425; 465 grams (with 32T chainring)
Chainrings: $99
Chain: $60-85; 250 grams
X-1299 Eagle Cassette: $420; 355 grams
Rear Derailleur: $289; 264 grams
Trigger Shifter: $162; 122 grams
Grip Shift: $148; 140 grams (including clamps, cables, and Jaws lock-on grip)

X01
Total group: $1,193; 1502 grams (not including BB)
Crankset: $390; 465 grams (with 32T chainring)
Chainrings: $99
Chain: $60-85; 250 grams
XG-1295 Eagle Cassette: $360; 355 grams
Rear Derailleur: $220; 276 grams
Trigger Shifter: $127; 126 grams
Grip Shift: $118; 143 grams (including clamps, cables, and Jaws lock-on grip)