It doesn’t feel like long ago when 11 speed systems displaced the ever dominant 2x10 speed drivetrain. While there’s nothing wrong with 11 or even the 10 speed I was riding this time last year, there is some things to acknowledge and perhaps gain with this new 12 speed kick that has been sweeping the industry the past few years. Chances are when you step into your local bike shop or even demo a bike these days, you’ll see the bikes equipped with SRAM Eagle. Soon you’ll actually see these 1x12 systems go electric, but we’ll focus on the mechanical workhorses for the time being. I’ve spent some time riding the GX offering of SRAM’s Eagle since last summer and what a difference it has made to out-of-town trips to large hills and any mountains I dare traverse to.
As previously mentioned, I was still running 1x10 this time last year and had no true need to upgrade my drivetrain…or so I thought. A few trips to one of the largest mountain bike trail systems in Texas, Flat Rock Ranch, had provided a good sense of what I was missing after I swapped to the wide-range Eagle. When I’m not wrenching at my local bike shop, I can be found shooting photos at mountain bike races around the state. This involves me hopping on my enduro-capable bike with my 20lb+ camera bag and trying to muscle up the climbs to beat riders to the stages between transitions in attempt to capture their “race face”. Early on in 2018, I prepared for shooting the races on my 1x10 drivetrain by dropping my chainring size to the smallest my cranks would allow. This helped drastically, but I was still at a disadvantage with my 11-36t cassette to what the racers blessed with 11 and even 12 speed were riding. While that helped me grab all the photos I needed, it was a burden compared to using SRAM’s GX Eagle in January, this year, at the same venue. I expended a lot less energy than a year prior and even out-climbed some of the other riders even with all my camera gear and heavy glass planted on my back. I rode the same stages the riders set times on, pre-rided days prior and also climbed up and down all the fire roads connecting me all my desired photo stops; the GX groupset didn’t hiccup once. I even crashed my GX-equipped bike pretty hard at Flat Rock in October prior to the race in January! The rear mech took the impact and only bared scars from the rocks beneath the mud slapped onto the body of the derailleur. Shifting was hardly affected, but that was due to the hanger breathing its remaining breaths on the final few miles following the crash.
First-hand experiences aside, let’s see what makes the GX Eagle a significant player on the trails and how this workhorse drivetrain sets itself apart from the other levels of Eagle in SRAM’s lineup. Let’s begin by addressing the big cassette in the room; the large 10-50t range cassette of GX shares the same ratios as its two more expensive brothers, X01 and XX1 but with a slight weight penalty. This additional weight derives from the method of manufacturing; while the X01 and XX1 have their first 11 cogs carefully machined from one block of chromoly via CNC, the GX uses a more common practice of stamping and pinning steel cogs together. All levels of Eagle with exception to NX use an aluminum 50t cog. With exception again to the NX offering (Shimano freehub body), GX, X01 and XX1 mount to your hub of choice via XD driver. This freehub body allows the use of the tiny 10t cog perched at the end of your cassette. The chain is a simple 12-speed, Eagle-specific nickel-plated chain with no frills. It just works.
A large cassette requires a large derailleur. Everything about the Eagle derailleurs are large, in fact. Most notably the long-er cage than most on the trail. To keep things running smooth, even the lower jockey wheels have grown to 14 teeth. The X-Sync technology common in all of SRAM’s chainrings is even featured on the lower jockey wheel for added chain retention and silent operation. It goes without saying that there is a clutch involved. Specifically to SRAM, a roller-bearing type clutch. This roller-bearing style device allows the cage to freely move in one direction yet resist movement in the other; perfect for eliminating chain slap yet keeping the chain planted on the cassette. The GX rear derailleur uses a combination of materials such as aluminum, steel and stainless steel to keep this robust device on the more affordable end of the range. The X01 uses more aluminum throughout and the XX1 uses a carbon fiber cage. The shifter doesn’t receive much praise often, but the solid construction with aluminum trigger allow for the smoothest shifts with the weakest of thumbs. Climbing up the cassette block is so effortless it basically becomes thought. There is also a Grip Shift compatible with Eagle if you prefer to twist and rip!
GX is the last of the aluminum cranks until you get to the carbon X01 and XX1 variants. Forged out of 7000 series aluminum, these cranks combine the qualities of lightness, durability and affordability. Available in GXP and the new DUB spindles, different crank lengths, these cranks also feature a direct-mount chainring interface. This allows for a lower weight product by eliminating the spider and a better chainline by fitting the chainring of choice securely with 3 hidden bolts behind the drive-side crank adjacent to the spindle. Chainrings are made from aluminum and can be purchased in sizes ranging from 30 to 34 and even oval offerings! I’ve banged my cranks on rocks, logs and even curbs and ledges with just cosmetic nicks and scrapes. No concerns with their structural integrity or reliability. I can’t say the same about the chainring, however. One good smack on a rock and I lost a tooth…well the bike did. This can happen to any chainring really, so it’s more user-error and lack of a bashguard than a jab on SRAM’s build quality.
After hundreds of diverse miles under my tires and on my GX drivetrain, I can’t speak more highly of this 12 speed variant. It’s gotten me from point A to point B where it can make or break photo opportunities, allowed me to clean the most technical sections and simply gave me the freedom to experience more trails with more energy conserved for the long hauls. I’ve seen enduro racers sporting the most expensive equipment known to man and some that use the more affordable, though heavier drivetrains available from SRAM and other manufacturers. It’s all down to budget and weight, in all honesty. Even the lowest-end NX offering shifts buttery smooth with as little effort and all the gear range you can get with the XX1. The best part is all SRAM Eagle drivetrain levels are cross-compatible, backwards, forwards and all directions. You can put your money and weight where you want it and still come out with a robust and quality drivetrain that just works. For a solid and affordable 12 speed drivetrain, it’s hard to go wrong with the GX Eagle.
SRAM GX Eagle DUB Groupset available here for $545.
Words and photos by Mike Cartier.