Our test Hightower in Plus and Eagle garb.

Our tester Santa Cruz Hightower looking good in plus and Eagle garb.​

Lowdown: SRAM Eagle 1x12 Drivetrain

At this point we've all grown a little tired of new mountain bike standards, but just like disc brakes and tubeless tires, if it proves its benefit the tribe embraces it. This is the key question we'll attempt to answer in this review. Does SRAM Eagle 1x12 provide a significant riding benefit, what is it, who benefits? The other question is, how well is it engineered and manufactured to perform the task? Will it survive the demands of aggressive mountain biking? Read on for answers. Also be sure to check out our First Ride Review and get up to speed on all Eagle's tech specs here.

Number of gears: 12Price: XX1 $1417, X01 $1193
Gear Range: 500%Rating:
5 Flamin' Chili Peppers
5 out of 5
Weight: 1456 grams, 1502 grams
Stat Box


  • Huge gear range with consistent jumps
  • An occasional pop in the rear chain and cassette
  • 300 grams lighter than 2x with similar range
  • No current option below X01
  • Light and strong cassette
  • 50t ring color calls attention to itself
  • Seamless shifting
  • Not compatible with current 1x11 systems
  • Same range as 2x and 3x systems
  • Ground clearance on par with 1x11
  • Light, push-button like shifting
  • Uses existing XD driver freehubs
  • GripShift option available

Review: SRAM Eagle 1x12 Drivetrain

We've ridden the SRAM Eagle 1x12 on about five different bikes in all kinds of conditions over the last four months and the experience can be summarized in one word: Seamless. It just performs without calling attention to itself.

The XO1 group in all its glory.

The X01 group in all its glory.​

The most remarkable quality of Eagle is the final shift, the big jump from the 42t to 50t, happens without any drama. There is no hesitation or additional pressure on the trigger shifter. Likewise going down from the 50t to the 42t. How this occurs so smoothly is a true engineering marvel, because we've experienced the struggle with other 'mega' range systems before. In fact, with Eagle, we've often looked down at the gear cluster and asked, "Did that big shift really just happen?"

Ace racer and mechanic Duncan Riffle paid us a visit in Santa Cruz to do a pro install of the Eagle.

Ex-pro DH racer turned SRAM PR man, Duncan Riffle, paid us a visit in Santa Cruz to do the install of our test Eagle group.​

The shift quality rivals 1x11 or even 2x10. And in the Mtbr forums some have even said it's better than their SRAM Red, or Dura Ace, or even Campy. It just works.

X01 Eagle cassette weighs in at 354 grams.

The SRAM X01 Eagle cassette weighs in at 354 grams.​

Ground Clearance

This is the common pre-ride complaint, as new users are concerned that their rear derailleur will get ripped out since one theorizes that the derailleur hangs lower. But SRAM has figured out how to tuck the derailleur tighter and they say the ground clearance is the same as with 1x11 systems. We certainly had no issues.

X01 cranks come in at 526 grams with a 32t ring.

SRAM X01 Eagle cranks come in at 526 grams with a 32t chainring.​

In our experience, there has been no issue with the derailleur getting caught at all. We're sure it will happen to someone some time, but not at a frequency more common than on 1x bikes. The other factor to note is the derailleur is at its lowest point when it's on the 50t cog. But that's typically when speeds are low, as the bike is usually crawling up a hill. At ballistic speeds, the derailleur will be tucked in at a higher gear.

Continue to page 2 for more on SRAM Eagle 1x12 »

X01 rear derailleur comes in at 279 grams.

SRAM Eagle X01 rear derailleur comes in at 279 grams.​

Best Beginners and Intermediates

Plenty of riders love 1x11. Its usability allows you to focus on the riding without worrying about a front derailleur. Shifting performs better since there are no duplicated gears and there is no planning required to make the front chainring shift. Plus it frees up the left side of the cockpit for the dropper post lever.

Uncut chain is at 244 grams.

Uncut chain is at 244 grams.​

But many riders are simply over geared with 1x11. Either their hills are too steep and long, or their power to weight ratio is lacking. Often they find themselves at the lowest gear at the bottom of the steep hill. The resourceful ones will optimize the bike and install a 30t front ring or gasp… a 28t. It works but it's certainly a compromise because of the sacrifice on the high end.

With Eagle, there is a 500% gear range instead of the 1x11's 420%. This is the breath of fresh air that riders have been looking for. It addresses the needs of those that need that extra range. It makes gear selection more seamless, as one is not compelled to play the gear management game of saving a gear or saving the last ounce of strength.

Compared to an iPhone 6 Plus, the Eagle cassette is not dwarfed.

Compared to an iPhone 6 Plus, the Eagle cassette is not dwarfed.​

Better for Advanced Riders

For riders who are fit and have the power to turn the 1x11 gears, they are fine and don't need to be forced into spending dollars on this new gear range technology. But if they choose to, there is a benefit as well. Simply put, Eagle is a faster system. With a bigger range of 500%, even the fast rider will not run out of gears when they slow cadence down or go in conserve mode. And on the high range, on a very fast pedal segment, the rider will have less chance of spinning out because you can run a larger chainring up front.

The magic of the Eagle cassette is the smaller rings are forged from a solid hunk of steel giving it incredible strength.

The magic of the Eagle cassette is the smaller rings are forged from a solid hunk of steel giving it incredible strength.​

Indeed, the advanced rider can opt for a 34t ring instead of a 30t. This delivers a more efficient drivetrain with less drag, and it works more efficiently with most rear suspension systems, inducing less pedal bob. It gives the rider a better opportunity to match the front ring for performance, rather than necessity in order to make it up a steep hill.

Weight for our decked out Hightower is at 27.56 lbs with Plus Maxxis HighRoller tires.

Weight for our decked out Hightower is at 27.56 pounds with plus-sized Maxxis HighRoller tires.​

Bottom Line

If it's better than 1x11 for beginner riders, advanced riders, and everyone in between, then is it a better system? We say, yes. But it is one of the more expensive groups at the moment and our hope is that this technology trickles down to more price points sooner rather than later. Then it will really be a game changer.

To learn more please visit www.sram.com.