In four days of hard testing we never dropped our chain, or even had a miss-shift.

In four days of hard testing we never dropped our chain, or even had a miss-shift.​

The first thing you notice about SRAM's new Eagle 1x12 drivetrain is that it doesn't feel much (if at all) different from the popular 1x11 systems most of us are already used to. Assuming proper rear derailleur adjustment, shifting is rapid and precise, each push of the shift lever quickly followed by movement of the chain and a reassuring "thunk" that action has occurred. Honestly, in a blind "taste" test you'd be hard pressed to tell the difference… until you jump into that 50-tooth cog.

Indeed, while SRAM has trumpeted a host of non-gearing related improvements between its 1x11 and 1x12 drivetrains, it's the gearing that will always draw the most attention. With the addition of that dinner-plate sized cog, you now have a full 500% range, which on the bike feels a lot like what you get from a traditional 2x system, just with one less derailleur and shift lever.

That last jump from 42- to 50-tooth cog looks massive, but in fact it felt normal at the lever.

That last jump from 42- to 50-tooth cog looks massive, but in fact it felt normal at the lever.​

That later fact was noticeably important during our first thumb-to-shifter encounter with SRAM Eagle at a recent Scott Bikes press launch in Lenzerheide, Switzerland. While we were impressed with the new Spark and Scale XC bikes, the constant presence of Scott's dual-lever TwinLoc system on our test bike handlebars occasionally made things feel a little crowded. But when you add a 50-tooth cog to the equation, the front derailleur becomes obsolete, which forever minimizes cockpit clutter.

Get all the tech, weights, and pricing details on the new SRAM Eagle drivetrain here.

The best way to understand the gearing benefit of Eagle depends on past experience. If you've spent time on a 1x11 set-up with say a 32-tooth chainring paired to the 10-42 cassette, then making the switch will net you a higher high and lower low if you opt to jump up two chairing teeth to a 34. Or if you're happy with your current climbing gear, you can jump up four teeth to a 36, which will maintain your current uphill gear, but add some top-end for your next enduro sprint. (Currently SRAM is offering chainrings from 30- to 38-tooth, which is what XC superstar Nino Schurter has been running since making the switch to Eagle.)

Meet reigning XC world champion Nino Schurter's Scott Spark RC 29er race bike, complete with SRAM Eagle drivetrain.

Meet reigning XC world champion Nino Schurter's Scott Spark RC 29er race bike, complete with SRAM Eagle drivetrain.​

Most of the Eagle spec'd Scott test bikes we rode during the four-day event in Switzerland had 32s up front, which for me meant easy spinning on the climbs, as I usually run a 30t on my 1x11 set-up back home. And while, I'm usually content on steep climbs, I have to admit it was nice to sit and spin at 70-80rpm once in a while, rather than grinding it out as is usually the case.

If you spend your time on a 2x set-up, the final shift from the 42 to the 50 will feel very familiar, as that 8-tooth jump is very close to the 10-tooth jump on a typical double chainring.

Durability is a big part of the new system, according to SRAM. Even in harsh conditions it's billed to last longer than its predecessor.

Durability is a big part of the new system, according to SRAM. Even in harsh conditions it's billed to last longer than its predecessor.​

As for that big jump, it may sound like a giant (and perhaps awkward) leap, but the actual feeling of the shift is essentially no different than the rest. Just like a 1x11 10-42 cassette, the Eagle tooth count for the first 11 cogs is the same (10-12-14-16-18-21-24-28-32-36-42). What you might notice is that the spacing between cogs is slightly narrower, and the 50-tooth cog is 2mm closer to the spokes than if you were running 1x11. But don't fret; Eagle works just fine with standard XD driver bodies, so you wont need to do a bunch of freehub swaps.

Continue to page 2 for more of our SRAM Eagle first ride review »


There is a rotor behind that 50-tooth cassette somewhere.

There is a rotor behind that 50-tooth cassette somewhere.​

You'll also notice that the size of the 50-tooth cog looks downright strange. It's roughly the size of a 200mm rotor, which from a straight-on angle yields the mountain biking equivalent of a perfect solar eclipse. Despite the size, the 8-tooth jump is right in line with the 19% jumps along the rest of the cassette. Bottom line, it all feels surprisingly natural.

What wont feel natural is the fact that in order to make the switch you'll have to ditch most of your old 1x11 parts, as there is limited cross-compatibility with the two systems save for being able to use 1x11 cranks with Eagle as long as it's compatible with a direct mount chainring with removable spider. You can also use Eagle chainrings with 1x11 systems. And while that might seem odd, it's actually worth considering if you don't have an extra $1417 sitting around for a new XX1 Eagle group (which is what we tested), or $1193 for the more enduro-oriented X01 Eagle group.

The Eagle chain has fewer sharp edges, which reduces cassette and chain wear. It's also easy to find the master link.

The Eagle chain has fewer sharp edges, which reduces cassette and chain wear. It's also easy to find the master link.​

Turns out the Eagle chainring has a fully revised tooth profile that SRAM claims helps more evenly spread the load of the chain around the ring. This nets smoother and quieter operation, which in our four days of riding, we can vouch for. This Eagle is smooth and quiet like a stealth bomber.

This silky operation is also attributable to the new SRAM Eagle chain, which the Chicago-based company says is the best it's ever made. Getting there, though, was a highly involved manufacturing process where each link's plates are made flatter and smoother. This means fewer sharp edges, which reduces cassette and chain wear.

As for set-up and maintenance, we can't tell you too much yet, as Scott brought in a fleet of mechanics (including some from SRAM's Germany office) to assure bikes were running smoothly. Despite that, a few of our fellow scribes did have some chain-skip shifting issues during test rides, though that never happened to us.

Shift levers come in either trigger or twist. Our time on the trigger set-up was drama free.

Shift levers come in either trigger or twist. Our time on the trigger set-up was drama free.​

Near the end of the event, Chris Hilton, SRAM's product manager for mountain bike drivetrains said simply that like with any bike part, set-up is everything. "That's the case with anything, tire pressure, brakes, rear derailleurs," Hilton said. "Every Eagle rear derailleur comes with little red tool that will help you get the exact correct chain gap, because it does need to be set up correctly. Chain gap is everything. There are also some great videos on sram.com."

Scott is spec'ing the new 1x12 drivetrain on everything from 1x-only hard charging hardtail XC race weapons, to laid back plus bike fun machines.

Scott is spec'ing the new 1x12 drivetrain on everything from 1x-only hard charging hardtail XC race weapons, to laid back fun machines such as this Scott Spark Plus Tuned.​

We can't address set-up issues any further, or vouch for system durability claims. But based on our limited test time and general love of 1x shifting, we'll offer this: If you can stomach the small weight penalty and price hit, there's likely no reason not to jump on this Eagle's wings when it's time for a new drivetrain.

For more information, please visit www.sram.com.