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SRAM GX Eagle Rear Derailleur

Average User Rating: (Very Good) Vital Rating: (Very Good)
 SRAM GX Eagle Rear Derailleur  SRAM GX Eagle Rear Derailleur
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First Look, First Ride: SRAM GX Eagle Drivetrain - More Range For All

Just $495 gets you SRAM's new wide-range 1x12 GX Eagle drivetrain. Best of all, the various components are compatible with top tier XX1 and X01 Eagle systems.

Rating: Vital Review
First Look, First Ride: SRAM GX Eagle Drivetrain - More Range For All

When you look back at the history of SRAM's 1X drivetrains, it took quite a while for all that wonderful technology to trickle down to a price point that many considered to be affordable. Three years and multiple intermediary drivetrains separated the 2012 introduction of XX1, the company's flagship 11-speed system, and GX, the affordable workhorse. That's not the case this time around. SRAM is making moves by releasing an everyman's GX version of their new 12-speed Eagle drivetrain just one year after it launched. Let's dig in...


GX Eagle Highlights

  • Fits existing bikes with XD drivers
  • 12-speed 10-50 tooth pinned cassette with 500% gear range (10-12-14-16-18-21-24-28-32-36-42-50 teeth)
  • 7000-series forged aluminum crank arms
  • Improved chain retention and wear characteristics with X-SYNC2 tooth profile
  • Direct mount ring construction
  • Type-3 Roller Bearing Clutch
  • Repositioned Cage Lock
  • MatchMaker X control compatibility
  • New chrome-hardened chain designed to reduce noise, friction, and wear
  • Complete Group Weight: 1742-1816 grams (3.8-4.0 pounds, claimed)
  • Group MSRP: $495-545 USD
  • Available August, 2017

Ask any Product Manager, "What's harder, making a top of the line product or something affordable?" It's often the less expensive product that demands the most effort. It's not terribly difficult to take a forged bit of aluminum or block of chromoly and machine it down to a precision component. All that machining time will be pricey though. To bring that same elegance and functionality down to a lower price point can be very difficult, however. Of course SRAM has some experience in this realm now, having stepped down from XX1 all the way to GX (and even NX) before.


Many of the key changes involve using different materials and manufacturing processes. You won't find fancy titanium or carbon in the GX line, but you will find reliable aluminum and steel. Forging, die-casting, and stamping are used to make the majority of the new GX bits. Much like 11-speed GX cassettes, they've used stainless steel pins to hold the 11 stamped steel cogs and one 50-tooth aluminum cog in place in a more economical manner. The open design is similar to SRAM's X-DOME cassettes to aid in mud clearance.


Of course there's a bit of added weight, but we're not talking anything huge. The largest gains are 115-167 grams (0.25-0.37 pounds) in the crankset and 95-grams (0.21-pounds) in the cassette over X01 Eagle. All of the other components differ by much smaller amounts.

We've seen that there's a huge calling for zero sacrificing performance, durability, and technology at a certain price point and we can no longer avoid that. That's something GX Eagle is really going to cover for us.

Most importantly, other than an adjustable shift lever, GX offers all the same features as XX1 and X01 Eagle systems. By making the switch from SRAM's 11-speed to 12-speed drivetrains, you're looking at an increase from 420% to 500% of gear range, vastly improved wear characteristics, a smoother feel, better chain retention, and the ability to back-pedal without issue, among other things.

The best part? Unlike some of SRAM's 11-speed groups, everything is compatible with all Eagle drivetrains. Mix and match as you please. All in, GX Eagle runs close to $700 less than X01 Eagle.

Specifications & Pricing



  • GX Eagle Crankset: $120-170 USD
  • GX Eagle Rear Derailleur: $110 USD
  • XG-1275 Eagle Cassette: $195 USD
  • GX Eagle Trigger Shifter: $40 USD
  • GX Eagle Grip Shifter: $40 USD
  • GX Eagle Chain: $30 USD
  • Entire GX Eagle Group: $495-545 USD

Actual Weights


SRAM's claimed weights check out on the scale. There's no fudging of the numbers.

  • GX Eagle Rear Derailleur: 291-grams
  • XG-1275 Eagle Cassette: 448-grams
  • GX Eagle Trigger Shifter: 122-grams
  • GX Eagle Chain: 263-grams

On The Trail

We met up with SRAM early this spring in Moab, Utah to sample the goods. Same-same, but different? It was our mission to find out as we checked off old and new Moab classics with the likes of Alex 'KrunkShox' McGuinnis (pictured) and Jon Cancellier, RockShox Product Manager, while also testing the new Pike fork and Reverb 1X remote. First we conquered Captain Ahab, then we set our fastest lap down Porcupine Rim, and we tackled Amasa Back to Jackson's to wrap things up – a truly rowdy and testing combo of trails.


We're quite familiar with SRAM's X01 Eagle drivetrain having spent over a year on it. The system is undeniably a better 1X drivetrain than its 11-speed predecessors. We're also quite familiar with SRAM's 11-speed GX drivetrain, which we've verified to offer pretty closely comparable performance to all of SRAM's 1x11 drivetrains in a more affordable package. It was with similar expectations that we set out on our GX Eagle test rides.

Shifts are clean when the drivetrain is properly adjusted and new. The range is there and the simplicity of a single shifter is there. Just like the higher-end Eagle drivetrains, the system remained quiet entering the easiest gear with no perceptible grinding through the cranks or by noise. While it is a large jump up to the 50-tooth cog, it's the type of shift that has you praising the drivetrain lords for granting you "one more" when you really need it. We had no issues backpedaling in any of the gears and the derailleur didn't back out.


What it lacks, however, is that ultra smooth feel of XX1/X01 Eagle. When most people hop on an X01-equipped bike they notice obvious improvements. Though all the technology updates SRAM made when introducing XX1/X01 Eagle are present in GX, we're not certain riders will be as impressed – at least based on our first few rides. Everything feels a touch more clunky and less refined. Why is that? It may be down to the precision lost by not machining the individual components. Visually, the GX Eagle cassette and chainring teeth edges are rounded, while XX1/X01 appear clean and sharp.

Additional quirks included a dropped chain on day two – albeit on a very rough section of Porcupine Rim – and a surprising amount of skipping under power on our test bike and others as each of our rides neared completion. When cables stretch a quick twist of the barrel adjuster can typically bring things back in line. What we experienced with GX Eagle is that cable tension can be a bit more finicky and difficult to dial in than on higher-end versions. This was also independently verified when another tester set up GX on a different bike that will be used in a long-term test.


What's The Bottom Line?

Though our initial impressions didn't wow us the same way XX1 and X01 Eagle did, SRAM's new 12-speed GX Eagle drivetrain offers riders the chance to mix and match affordable components thanks to 100% compatibility with other Eagle systems. That means substantial added gear range, the ability to once again spin up hills, vastly improved wear traits, and SRAM's many other improvements are much more attainable for all. At less than half the cost of the X01 version, it'll be interesting to see if the introduction of GX Eagle will encourage more bike brands to evolve their frames to 1X-only configurations to capitalize on the many associated benefits.

A long-term Vital MTB test of the new GX drivetrain has already commenced. X01 Eagle proved to be durable in the long term and we expect GX will as well.

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Vital MTB First Ride Rating: 3.5 Stars - Very Good

About The Reviewer

Brandon Turman - Age: 30 // Years Riding MTB: 16 // Height: 5'10" (1.78m) // Weight: 175-pounds (79.4kg)

"My current riding joys include pulling up hard and hucking test bikes into poor landings and techy sections with reckless abandon, then seeing how they react upon landing." Formerly a Mechanical Engineer and Pro downhill racer, Brandon brings a unique perspective to the testing game as Vital MTB's resident product guy. He has on-trail familiarity with nearly every new innovation in our sport from the past several years and a really good feel for what’s what.

SRAM GX Group in a box

The Good:

Eagle 12 speed

The Bad:

Tricky adustment

Overall Review:

SRAM GX Group in a box Watt On Wheels


Product SRAM GX Eagle Rear Derailleur
Riding Type Cross Country, Enduro / All-Mountain, Freeride / Bike Park, Trail
Speeds 12-Speed
Clutch Yes
Cage Length Long
Weight 0 lb 10.2 oz (290 g)
Miscellaneous X-HORIZON design
X-ACTUATION cable pull ratio
14-tooth X-SYNC lower pulley
Repositioned CAGE LOCK
52-tooth max capacity
Price $125
More Info

SRAM website

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