Last summer, I reviewed the newly released Sram GX Eagle drivetrain, and the long and short of it was: it’s a lot of bang for the buck. You get all the upsides of ditching the front derailleur with the fantastic gearing range of the 12 speed Eagle cassette, and at around $500, the whole kit is priced to sell.
But drivetrains wear out, so the big question was: how would the GX Eagle bits fare over the long term?
At this point, I have around 1,000 miles on the GX Eagle drivetrain that I reviewed (mounted on the Santa Cruz Hightower), and I have a few hundred additional miles on various other GX Eagle drivetrains that have been mounted to an assortment of bikes that have come through the review stable. For the most part though, this follow-up is based on my time on the drivetrain I originally reviewed. I’ve probably put around 175,000 feet of climbing on the drivetrain, and conditions ranged from dry and dusty to sloppy mud and snow.
I’ll offer the caveat that I’m not a huge guy, and I don’t lay down the kind of drivetrain-destroying wattage that some people do. But among a large group of riders, I’d guess that I put a fairly average amount of wear on the drivetrain.
Get To The Point, How’d It Hold Up?
Pretty well in most respects, but not without issues.
First, the high points: After all those miles, everything still shifts really nicely. There hasn’t been a substantial degradation in shifting performance in the time I put on the drivetrain (although the derailleur died — more on that below). The shifter is still working like new. The cranks have some rub marks from my heel, but they’re otherwise going strong. They’re still spinning smoothly, and despite smashing them on a bunch of rocks, nothing bad has happened.
Chain and Chainring
The chainring and chain are probably the pieces of the drivetrain that I’m most impressed with. The ring is still running smoothly, quietly, and it still holds the chain well. Sram made a bunch of tweaks to the tooth profile that look kind of weird, but the idea was to improve longevity. And from what I can tell, those changes worked really well — I’d say the chainring is lasting longer than any other narrow / wide chainring I’ve used, from any brand.
Here’s a picture of the chainring in its current condition — I’d say it’s showing very little sign of wear.
The chain is also still going strong. Now, I was using an X01 Eagle chain rather than the GX Eagle chain, so this isn’t an entirely fair test. But I actually have a bit more miles on the X01 chain than the rest of the GX Eagle kit, and it’s still in great shape. I stuck a chain checker on it and the wear indicator is sitting between “like new” and “very good.” So I’d say the chain is holding up better than average.
The cassette is also doing pretty well. Like the chainring, there’s a very small amount of visible wear, mostly on the top two cogs, but I’d still call it quite good. Overall, I’d say the cassette is wearing on the “good” side of average.
One odd issue that I did encounter with the cassette is that, as the cassette, derailleur, and chain broke in and tolerances became a bit less tight, there was a singular tooth on the 9th cog of the cassette that would interfere with the chain while I was in the 8th gear. One tooth lined up in a way that bumped the chain in that one gear combination, which caused the chain to skip. I think this is mostly an issue due to the cogs being spaced so closely together — it’s not something that I’ve ever experienced on any other cassette (although I have experienced it on other GX Eagle cassettes). Once I figured out the issue, a slight bend with a screwdriver to the offending tooth solved the problem.
You can see in this picture below how the chain sits very close to the tooth on the next cog down. (And yes, I know I should have cleaned my drivetrain before putting the bike away for the winter. I’m a terrible person.)
And that all brings us to the derailleur, which is the one place where I had a significant issue. As I noted in my initial review, setup is a bit fussy — when the spacing between cogs is this narrow, there’s less room for slop, and the adjustments need to be pretty close to spot on. It also means the drivetrain is less accommodating if the derailleur is slightly bent or a little out of whack.
Adding to this issue is the fact that the derailleur sticks out from the frame quite a bit, and the wide gear range necessitates a long derailleur cage that hangs pretty low. All that means that the derailleur is fairly prone to damage.
And, as could be expected, I eventually smacked the derailleur on a rock and bent it. The derailleur wasn’t visibly mangled, and initially, I couldn’t tell if it was the derailleur or the hanger that was tweaked (a quick hanger alignment confirmed it was the derailleur).
Once it was bent, the drivetrain still more or less worked — it was just a bit unhappy in 2 or 3 gears (and I could use the barrel adjuster to select which 2-3 gears were going to be skippy). This was annoying, but given that I’m lazy and try to avoid wrenching on my bike until it’s absolutely necessary, I continued to ride it like this for a while.
But eventually I sucked a stick and a bunch of tall grass into the derailleur cage, which bent things even more. And while I could still ride the bike, it reduced my usable gears to 3 or 4. Efforts to straighten and otherwise correct the derailleur were unsuccessful, so it was time for a replacement.
On one hand, both the initial impact and getting a stick caught in the derailleur likely would have damaged most other derailleurs too. I don’t think the GX Eagle derailleur is exceptionally fragile; it just succumbed to normal, derailleur-ending events. That said, I also think a lower profile derailleur (like some of the older Srams, or many of the Shimano derailleurs) might have escaped the impact either unscathed, or less scathed. And I think the extra length of the GX Eagle derailleur probably contributed to picking up the stick that bent it. A shorter, more tucked away derailleur might still be going strong.
And given that the bend in the derailleur wasn’t massive, I’d also guess that drivetrains with more space between each cog (i.e. 10 or 11 speed systems) might have been better able to accomodate the out-of-whack derailleur.
I’d also add that I’m skeptical that any other level of Eagle derailleur would have fared differently. I don’t think this is a problem with the GX Eagle derailleur bending easily, and I doubt that if I’d been running an X01 Eagle or XX1 Eagle derailleur, the outcome would have been different. In other words, I don’t think spending more money would have solved this particular problem.
My long(er) term test of the GX Eagle drivetrain more or less confirmed my initial conclusions — the biggest liability of the system is the derailleur, which is somewhat injury prone and the system is not particularly accommodating to a mechanism that’s out of alignment.
But that doesn’t get around the fact that the gear range is fantastic, the rest of the system performs impressively well (and wears well), and the price is still pretty damn competitive. It’s easy to poo-poo the system because I bent the derailleur. But I’ve been destroying derailleurs since the days of 8 speed, so that really isn’t anything new. And the dinner plate rear cog gets me up climbs that I’d otherwise walk, which is kind of tough to argue with.
And all that makes it tough to come to any kind of concrete, final recommendation. Are you the kind of person that breaks derailleurs a lot, or is your bike rarely in a state of proper adjustment? The Eagle drivetrains might be a frustrating experience for you. Do you live somewhere flat-ish, where the huge gear range isn’t really necessary? Then yeah, Eagle probably isn’t the answer to whatever your woes are. Do you have an ongoing, somewhat irrational love affair with the front derailleur? I think you’re a bit odd, but I know from experience that no amount of rational argument will get you to change your mind. Are you just itching to talk about the e13 cassette in the comments? Agreed, those are sweet. But they have their own durability issues, and they cost more than a GX Eagle cassette.
Long story short, after a lot of miles, I still think the Eagle drivetrains make sense and I still recommend them. Yes, there are downsides. But getting that kind of range out of a 1x system is fantastic, and at least for me, the upsides outweigh the downsides. As I said in my initial review, when it’s set up correctly, the GX Eagle offers most of the performance of it’s more expensive siblings at less than half the price, and that’s a helluva thing.