March 31, 2018
When SRAM launched their 12-speed XX1 and XO1 Eagle drivetrains last year, it didn't take long for riders to start asking “When does the cheaper version come out?” We're all familiar with how the trickle-down process typically works — a company starts by releasing the highest end, most technologically advanced model of a component, and then gradually rolls out different versions, each one with fewer features and a lower price tag than the previous iteration.
Well, SRAM's taking a different tactic this time around, cracking the floodgates wide open with the launch of GX Eagle, a 12-speed drivetrain that's half the cost of XX1 Eagle, but with almost identical performance. Yes, there is a weight penalty due to the different materials and manufacturing methods used to bring the price down, but the basics of the drivetrain remain the same — it's a single ring system, based around a 10-50 tooth cassette, which creates a 500% gear range.
The complete GX Eagle group retails for $495 USD, which includes cranks — you can knock a hundred dollars or so off that price if you already have a crankset that can accept an Eagle-compatible chainring.
The GX Eagle derailleur's uses the same basic design as its more expensive sibling, and from a distance you'd be hard pressed to tell them apart. It does use a stamped rather than forged cage, and the profile of the b-knuckle area is slightly different, but those changes only add up to a miniscule 9 gram weight penalty. Like the XX1 Eagle derailleur, GX Eagle uses SRAM's Type 3 roller bearing clutch, and a Cage Lock button that sits behind the clutch mechanism, allowing the tension to be removed from the chain for easy wheel removal.
The heart of the Eagle drivetrain is the massive 10-50 tooth cassette. When it first came out, it looked comically oversized, and there was plenty of scoffing from riders who swore there was no need for such a massive gear range. Those outcries aren't quite as loud anymore — it turns out that being able to spin rather than strain and struggle up a long, steep climb is a good thing, and if that easy gear is too easy, well, you can always run a larger chainring up front, and benefit from the increased top-end speed.
The GX Eagle cassette uses SRAM's Full Pin design, where the stamped steel cogs are held together with stainless steel pins, rather than being machined out of one piece of steel billet, à la the XX1 Eagle casette. Total weight for the cassette is 448 grams, and it retails for $195 USD.
The GX Eagle chain uses the same geometry found on its more expensive sibling, but a different finish (similar to what's used on SRAM's 11-speed X1 chain) and the use of solid pins allow for a substantial cost savings — at $30 it's nearly a third of the price of XX1.
The GX crankarms are 2D forged from 7000 series aluminum, and have a new shape that allows them to come in at 80 grams lighter than the previous GX cranks. SRAM's direct mount Eagle chainrings are backwards compatible with 11-speed drivetrains, which could make this solid replacement option for riders who need new cranks but don't want to spend an exorbitant amount of money. Available in 165, 170, and 175mm option, the cranks are $120 USD.
The position of the pull lever on the GX shifter can't be adjusted, and the finish is a little less smooth and shiny, but once again, the function is the same, with a crisp, distinct click each time the lever is pushed. Grip Shift fans haven't been left out either, and a GX-level twist shifter has been added to the mix.
I only have a handful of rides in on the GX Eagle group so far, but one thing is certain: the shifting performance feels almost the same as the pricier X01 group I had been running previously. Sure, the shift paddle lever might not be quite as smooth and shiny, but other than that tiny detail, I'd be hard pressed to tell the two groups apart in a blind test.
The transition between gears is quick and distinct, and although the jump to the 50-tooth cog is a touch slower than the shifting on the rest of the cassette, the chain still makes that eight-tooth jump with minimal hesitation. I haven't dropped a chain yet, and those inaugural rides included been plenty of rough and jarring trails — we'll see if that changes once some mud and grit is added to the mix, but given how well X01 Eagle performed, I don't expect GX to be any different. The long term performanc and durability of GX Eagle is the only question that remains unanswered, which is why I'll be putting plenty of miles in on it over the course of the summer to find out.