Sram GX Eagle Long-Term Follow-Up

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.

Noah Bodman reviews the Sram GX Eagle Drivetrain for Blister

Sram GX Eagle Chainring

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.

Cassette

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.

Noah Bodman reviews the Sram GX Eagle Drivetrain for Blister

Sram GX Eagle Casette

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.)

Noah Bodman reviews the Sram GX Eagle Drivetrain for Blister

Sram GX Eagle Casette — Closeup

Derailleur

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.

Bottom Line

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.

18 Comments

  1. Matteo April 22, 2018 Reply

    @NoahBodman: What durability issues have you had w/ E.13 cassettes? Most of the complaints I’ve encountered involve creaking & need to re-lube locking interface.

    • Noah Bodman Author
      Noah Bodman April 25, 2018 Reply

      Yup – that’s it, just some creaking. Perhaps “durability” was a poor choice of words; more of just an annoyance.

  2. Felix April 23, 2018 Reply

    Noah, great review, but are you really saying that you rode the 1.000 miles on ONE chain? Thats impressive.
    I usually replace the chain at 0,5% lenghtening to prolong the life of chainrig and cassette. So what does “between “like new” and “very good” mean in terms of percentage ?(my ParkTool chain checker indicates .5 and .7 percent)

    • Noah Bodman Author
      Noah Bodman April 25, 2018 Reply

      Hey Felix,

      Yup – I’m probably at around 1,100 or 1,200 miles on that chain. With a modern, high quality chain, that’s not unusual for me (like I said, I probably don’t put out the chain crushing torque of some heavier guys). I don’t recall off the top of my head which brand of chain checker I used on it, but I’m going to do some further investigation and try to come up with a more accurate description of how worn it is. I’ll report back.

      -Noah

  3. Blister Member
    Matteo April 23, 2018 Reply

    Word to the wise on SRAM 11 & 12spd chain wear: the “impressive” wear rate on new SRAM chains is an illusion that will have you replacing $$$ cassettes w/ unprecedented frequency! Based on my own experience w/ XX1 11spd & discussions of Eagle like the one linked below, conventional chain checkers that take chain wear measurements between rollers are not registering true overall chain elongation that will wear out a cassette long before your 11 or 12spd SRAM chain actually measures “0.5” on your chain tool. Turns out, the old-school method of taking a precision ruler and measuring pin-to-pin distance of 12 chain links is the only way to reliably catch a chain before it gets to a true elongation of 0.7% & reams out your cassette past the point of mating w/ a new chain without skipping.
    This was a *very* costly lesson for me to learn as I was swapping two XX1 cassettes on different wheels back & forth on a single bike/chain. When I went to replace my XX1 chain at what my Park CC-2 tool said was 0.5%, just to be on the “safe side” of protecting my $$$ cassette investment, both cassettes were already completely shot.
    TLDR version: ditch that chain gauge & buy a precision metric ruler!
    Discussion of how chain/cassette wear disparity has grown with Eagle below:
    https://www.vitalmtb.com/forums/The-Hub,2/SRAM-Eagle-chain-longevity-is-impressive,9934

    • Felix April 24, 2018 Reply

      Matteo,
      thanks a lot for this unexpected angle on the wear issue. I have read the discussion under the link you provided. What I still not get is WHY a conventional chain checker would not give a valid result. Are the chains too narrow for the checker to fit in laterally, even when elongated to e.g. 0.8%?

      • Matteo April 25, 2018 Reply

        @Felix: I honestly haven’t been able to puzzle that out myself. It’s not “narrowness”: 12spd chains are only marginally narrower between plates than 11spd, and the pins on my cam-actuated Park CC2 have plenty of clearance.
        It may have to do with how the SRAM rollers sit on the flared shoulders of the side plates that center them. Perhaps they move more under full pedaling force than the light tension chain checkers generate (you’d damage them if you attempt to apply even a fraction of full pedaling torque). All I know is that the tool I used to accurately monitor wear on 8-10spd chains by KMC, Shimano & SRAM no longer registers true overall elongation of 11-12spd SRAM chains. Measuring w a ruler at the rivets to take rollers out of the equation seems to be the only solution.

    • Noah Bodman Author
      Noah Bodman April 25, 2018 Reply

      Hey Matteo,

      Good points – I’m going to do some more accurate measuring of the chain, and I’ll report back with what I come up with.

      -Noah

      • Felix April 25, 2018 Reply

        All geeking out, I just checked the GX 1×11 chain (Sram CN-PC1110) on my bike with slightly confusing findings: While the Park Tool Chain Checker slipped in frictionless with the .5% side, the external 12-inch ruler method showed visibly less than 306mm, translating to about .35% elongation.
        Could it be that the thickness of the rings around the pins vary between chain types?

    • non April 25, 2018 Reply

      i went and measured mine, and indeed, my regular measurement thing wouldn’t be very useful as 0.7% is about 2.1mm over 30cm (which is +- 12 links)

      that said mine measure the same as a new chain within 0.1mm (yay!) even thus its quite old. i do take very good care of it (good oil, often cleaned, cassette is clean, etc.) I bought 2 chains and the 2nd has been sitting in the drawer forever lol. all that to say while you’re absolutely right and im glad i’ve seen your comment, the chain still seem very durable to me so far

  4. Blister Member
    Matteo April 23, 2018 Reply

    PS: here’s the math for the 12-link ruler method:
    measure 12 links in the chain, center of pin to center of pin.
    12 links in a new, unworn chain = 12″ (304.8mm).
    0.5% wear over 12 links = 1.524mm

  5. Lloyd April 23, 2018 Reply

    I have a bent tooth interfering with chain skip in the exact cog as you. I also have one broken tooth on the 8th gear. My GX Eagle is only 150klm old. The cassette I think is a little weak and tight tollerences so prone to this damage compared to 11 speed. How do you figure XT is the same price? In Australia a gx 12 speed cassette is $300, and XT 11 is $130. Nice review!

  6. Morten April 23, 2018 Reply

    Why use a X01 Eagle chain rather than the GX Eagle chain? Would you recommend using a X01 or XX1 chain on the GX drivetrain?

    • Noah Bodman Author
      Noah Bodman April 25, 2018 Reply

      Hi Morten,

      I just used the X01 Eagle chain because that’s what was already on the bike when I installed the GX Eagle drivetrain, and my GX Eagle kit didn’t include a chain. Don’t take that as any sort of opinion on the quality of the GX Eagle chain though – from the time I’ve spent on the GX Eagle chain (around 200 miles), they’re fine, and they seem to wear well.

      -Noah

  7. non April 25, 2018 Reply

    im surprised how reliable it is myself. granted i run xx1 eagle not gx eagle but they seem to be built very similarly anyway. i havent changed the chain, cassette, or ring since i bought it on release month.. i changed my road bike cassette twice and the chain like 6 times in the same amount of time and it doesnt really get ridden that much more.

    also was scared with the derailleur but never broke it. worse i got is grass getting stuck in super tall super grassy areas. it is indeed a little fussy to setup though it doesnt not seem to move or need readjustments once its set right. I suspect that while its more likely to get hit, its not *that* much more likely than a regular derailleur. The main reason is that the times you’re crashing or going fast you’re generally on a harder gear and the derailleur is mostly out of the way, not much differently than on a regular xx1 system. its only really exposed on the 3 top cogs/easy gears, where you’re less likely to crash

  8. Miha Bencan August 6, 2018 Reply

    This is a very spot on review, as usual from Blister.
    My experience with GX Eagle is also not very good. In the past 3 seasons I needed to replace exactly 0 rear derailleurs. That all changed with the arrival of GX Eagle groupset on my Remedy 8. 3 derailleurs in 3 months says something. This thing literally stops working properly the first time you hit any sort of trail debris, which of course you will, because the derailleur sticks out quite a bit.
    I think the GX Eagle is a flawed product. Because any mountain bike drive train, that stops working after the first minor hit is simply not suitable for mtb use. Talking to shop mechanics confirmed my findings. Several other people had exactly the same issues.
    I will convert my bike back to 11 speed, which in all honesty offers enough range, is lighter, more durable and simply works, even when the derailleur looks like it should not.

    • Felix August 22, 2018 Reply

      Miha, do you see that problem with all Eagle derailleurs or only/specifically with GX Eagle derailleurs?

      • Miha Bencan September 7, 2018 Reply

        Hi, well my sample size is not that big, but recently I rode a X01 Eagle groupset and in a muddy race I did, it did not impress me at all. It had all the same symptoms of the GX groupset. I think the problem is in the very tight chainring spacing in the cassette.

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