[The Jaisah]

I have been running GX AXS on my Specialized enduro for a few weeks now, coming off of a normal GX drivetrain with the 10-52 cassette. Been running analog GX for a couple years and never had any issue apart from bending cages. The clutches always seemed to be strong. However with this AXS derailleur I've noticed very excessive chain slap as if the clutch is just super weak. And keep in mind the first AXS derailleur I put on was warrantied, it wouldn't shift out of the bottom cog without a double click, throwing off the rest of the pull. That first derailleur had this issue for me as well though. My Enduro has never been this loud until now. Same cassette and chain I used to run, only new variable is the AXS. Anyone else experiencing a similar issue when they switched over to AXS? Any cures or is this just how it goes?

I have the same issue. I got the Stumpy 15 Expert and I just took it in for its first service. I told them about the clunk/clack sound and even showed them a video (I was filming some of my rides with chest mount action cam). They have had a really thorough look at it and compared with some other bikes that also have the GX AXS T-Type and they all have really bad chain slap which is where the noise is coming from (they filmed in slow-mo with someone doing bunny hops and confirmed it is the chain slapping). I'm pretty pissed. This bike is awesome and so quiet but as soon as I get on some slightly chunky terrain is clack clack clack the whole time. They happened to have a SRAM XX cage that was lightly used off another bike that they put on to see if it would fix the problem (it's lighter because it uses some titanium instead of steel) and they said it's better but still not fixed. I would be happy-ish if they were doing this fix for free but they want to charge me for this. The GX derailleur is faulty man. This is not acceptable for a derailleur that costs so much money but causes chain slap on a $12k NZD bike. This is not cool. I wonder if we get enough people complaining to SRAM if they will do a recall or provide some sort of fix.

Here's one of my videos. If you skip to 50 seconds you can hear it clacking on every bump.

UPDATE: I went to speak to them at lunch and said I don't want the new derailleur cage coz I don't want to spend more money on a problem that shouldn't even existing on a brand new Specialized. They said they would talk to Specialized and actually found that my bike has an early model chain stay protector and the newer ones have a lot more pronounced ridges on them so they are going to swap out my chain stay protector with the one that is on the other Stumpy 15 in their shop and we will see if that fixes/helps the problem. Fingers crossed. I'll pick it up after work. It's not the end of the world, it's just a clunking sound but the bike is otherwise so quiet and pleasant and fantastic to ride so it's kind of just a turd in the soup when it clunks down over every root, rock and drop.

Update #2: The different chainstay protector didn't fix anything so it's either a bad design on the chainstay protector or a bad design on the clutch of the mech or more likely a combination of the two. They are going to fit some STFU chain guides free of charge. I'm not a fan of the look of them but I'm sure they will work well to stop the noise.

 

[The Jaisah]

This little washer/shim really helped quiet down my AXS derailleur, on both bikes. Worth a shot for a few bucks!

Super Shims – Madrone Cycles

It's still at the shop. They didn't want to send me away without a fix so they said they will order in some of those STFU chain guides and fit them which they did earlier today but it didn't fix the issue. Now they think that it is actually hitting the cage of the derailleur. The guy said he will talk to his boss and see if they can swap my derailleur with a demo bike that has the same derailleur to see if that fixes the issue and they will send mine away to get checked out. It sounds like the GX AXS T-Type derailleurs just have insufficient damping on their clutch, or maybe it's just my one. I left it with them since the weather is atrocious right now so I can't ride anyway and I also have an e-bike that I can ride in the mean time. I'll wait and see what they come up with. Sounds to me like either a faulty derailleur or a really bad design by SRAM.

Edit: I had a look at that link you sent but they don't show T-type in the listing. Will this work on T-Type?

 

[The Jaisah]

Update: They still have the bike. The STFU chain guides didn't do anything. After trying this and realising it made no difference they thought it might be the sound of the chain hitting the derailleur cage but now they think it might be the chain hitting the underside of the chainstay? They have been using slowmo video to try to see what the chain is doing when they bunny hop it. So they have ordered a chain guide or guard, I couldn't quite understand what he said on the phone. These guys are really putting a lot of effort in to try to solve this problem for me so I'm pretty grateful for that. Hopefully this solution will stop the sound or at least dull it down a bit. I'll know in 2 days when I pick it up. Nobody else has a Stumpy 15 that can comment if they have the same clacking sound when going down rough terrain? The bike is super silent until I hit gnarly terrain or drops and then I can hear the chain hitting something.

 

[The Jaisah]

I have a new Stumpjumper 15 with XO t_type and on rough terrain it's miserable. Have talked to SRAM and they gave a whole spell about how good their clutch is and nothing is wrong. It was bad enough I had my first derailleur warrantied and second one is just as bad. Specialized says they heard of the issue and said to check with my shop about a frame issue. Even sent my shock to Fox to confirm it was OK. Bike is awesome otherwise but I'm not sure I can live the clunking and chain rattle. I coasted some downhill trails with no chain or derailleur and the issues were gone. My shop thinks I need to spend a bunch of time trying different shock settings repeating a section of trail over and over changing one thing at a time but I know my tire pressures and shock settings are good. 99.9% that won't solve anything. It's a shitty derailleur. Simple as that. They way the shock uses a lot of travel easily may contribute to the issue as well.

Damn bro that sucks!! Tell your shop to talk to Specialized because they must be getting a lot of complaints from people about this. My bike is still at the shop. They tried fitting a chain guide and there's no improvement. They are waiting for Specialized to tell them what to do next. Out of interest, what size is your bike/frame? Mines an S5 and the shop said that the S4 and lower hasn't had any issues but the S5 has a longer chainstay so maybe it's something to do with that? They are still looking at the way that the chain slaps onto the chainstay but I don't think that is the issue. It's fully coated in rubber so if the chain hit that it would just be a dull thud not a clack sound. I reckon it must be the sound of the chain hitting the derailleur cage or something like that. And this might be worsened by the derailleur clutch not being strong enough or something like that. They have tried a lighter cage, and it made almost no difference. Hopefully Specialized will come up with a proper solution to the problem because I am guessing there are thousands of people out there with the same issue.

 

[The Jaisah]

Dang! I have a S5 too. Glad to hear it's not just me. SRAM and Specialized admit nothing and act like it's just me. My shop also thinks I'm a bit nuts for how many times I've been in there and complaining about my bike. I'm sure suspension adjustments are not it. I'm on a Facebook Transmission group and few guys have said the Stumpy is noisier than most with T-type. Another guy mentions suspension design and the way the Genie works. I talked to an old friend again last night who lives in another state and is a great bike mechanic and we hashed out a bunch of ideas and came up with this to try: Use the setup cog 7 and 118 chain length. I have a 32 front ring. Set up calculator for an unknown bike with 445 chain stays says position A and setup under SAG. So I'm going to partway start over on setup. Micro adjust to middle (7). put chain in small cog lock out cage and take back wheel off. Change from B to A and put derailleur in setup mode, loosen derailleur and shift 5 times to gear 7. Put wheel back on. Leave axle and derailleur a little loose. Go to shop or have someone help you with this. Sit on the bike and have the other person pull back the derailed and tighten everything under sag. A few guys on Facebook mentioned doing it under too. After living with this and trying every other thing, this might be it? Excited to try it today. What we worked out last night is that with the longer stays, like you said and shock motion when you you have it set up how the instructions say it's not enough tension. When you are on the bike compressing it weighted going through rough terrain the tension on the chain becomes way too little. Setting it up under sag may compensate for that. I think this might do it. It makes a lot of sense to me. I'll know in the next day or 2 and post my findings.

Damn bro I'm sorry to hear that your shop is not playing ball! I look forward to hearing your findings. It sounds promising! Also if it doesn't fix it, try to get some videos of the issue. My bike shop looked at the bike for me but then kinda brushed it off initially but when I said I had a video of the sound they straight away started taking it a lot more seriously. Not saying that they were not being helpful because they were, very good guys at this shop, but when they heard the sound in the video they straight away were like "Nah that's not right. It shouldn't be making that sound." and since then they have spent a lot of time trying different things and liaising with Specialized so the video definitely helped to escalate the response.

 

[The Jaisah]

Any update on this? I love my Stumpjumper but I am getting a bit fed up with the clunking. It definitely sounds like it’s coming from the derailleur.

 

[The Jaisah]

My shop guy rebuilt my rear hub with lighter grease and that helped a tiny bit but didn’t solve it. I’m pretty sure it’s the derailleur too. It’s winter here and hard to try things now but I’m going to try a different shock I have to see how that affects the back end movement. Curious if that would change the derailleur clunking? I also want to try shorting the chain a little. If those do nothing I will put my XT drivetrain on and tape the cable to frame and try that. I really like my Stumpjumper too but am also sick of the clunking sounds.

Damn I was hoping my you had a fix haha. Honestly I don’t think switching out shocks is going to do much. I have tried running the genie shock with 1 (stock), 2 and 3 spacers and with the it’s way firmer than with 1 and it still clunked as much, if not more than the stock setup. The derailleur is unsprung so I don’t think it’s really affected by the suspension at all. There is pedal kick back and stuff like that but that has a very different, higher pitched sound. When I pull the derailleur cage all the way forward and release it it makes a similar clunking sound so I’m 90% sure it’s just a badly designed derailleur or faulty derailleur. When I take it in for its next service I will get them to check the derailleur. They had previously said that they could send it away to have it checked by SRAM.

 

[The Jaisah]

I was just talking to Specialized directly and the guy that I spoke to also has an S5 Stumpy 15 but with the Ohlins suspension. He said he had the same issue with clunking and managed to fix it by setting up the derailleur correctly. He sent me this video and said the steps at 7:50 are the most important and that the derailleur needs to be pulled back tight while torquing the bolt to 30Nm. I'm sure the shop has tried this already but in the hopes that I can get this fixed, I will take it back to them tomorrow to get them to set it up again. I'll update you once the work is done.

 

[The Jaisah]

I’ve done that and even marked the position of the line with tape and pulled it back a little more. Have also had my shop guy pull it back and tighten it with me sitting on bike. Didn’t help. I’m considering taking 1 link out to make it 116 links instead of the 118 speced and see if that helps. I sent a whole long email to SRAM, again, and they think it’s the chain hitting the frame and making that noise by resonating through the tubes. I have rubber everywhere the chain could hit frame. They said to get a STFU. You already tried that with no luck. I also want to wrap my chainstay with some thing like a pool noodle or pipe insulation sleeve just to see for sure. It’s full on winter right now so hard to really try stuff at the moment. Frustrating…

Damn bro that sucks. The guy I spoke to said it fixed the issue for him. Maybe he did something special when he did it. He mentioned he torqued his to 30Nm but I looked in the manual and I'm pretty sure it says 25Nm so maybe that's the secret? More torque? Either way I will drop it in to them tomorrow and get them to talk directly with the guy I spoke to and fingers crossed they can sort it. I will let you know either way.

 

[The Jaisah]

I have a new Stumpjumper 15 with XO t_type and on rough terrain it's miserable. Have talked to SRAM and they gave a whole spell about how good their clutch is and nothing is wrong. It was bad enough I had my first derailleur warrantied and second one is just as bad. Specialized says they heard of the issue and said to check with my shop about a frame issue. Even sent my shock to Fox to confirm it was OK. Bike is awesome otherwise but I'm not sure I can live the clunking and chain rattle. I coasted some downhill trails with no chain or derailleur and the issues were gone. My shop thinks I need to spend a bunch of time trying different shock settings repeating a section of trail over and over changing one thing at a time but I know my tire pressures and shock settings are good. 99.9% that won't solve anything. It's a shitty derailleur. Simple as that. They way the shock uses a lot of travel easily may contribute to the issue as well.

So did you remove the derailleur and chain and go down some rough terrain and the bike was completely silent? Even over bumps/drops? I saw the SRAM rep today at the shop. He was going to re-setup my bike to just triple check that the shop had done it correctly. When I saw him he hadn't started yet but he gave me the same slippery vibes that you got, claiming that the derailleur is perfect and that it must be an issue with the frame or something. I can't stand people like that. I told him that "someone on a forum has the same bike, took off the chain and derailleur and rode down some trails and it was silent" and his response was "I never believe anything I see on forums they're all keyboard warriors" which is just frustrating BS from a slippery c**t. Anyway, I will pick up my bike soon when work finishes and I'll see what they say. If this doesn't fix it then they will send my bike back to Specialized to get them to look at the frame/everything and resolve the issue once and for all.

 

[The Jaisah]

Update: When I picked up the bike they said they couldn’t find anything wrong with the derailleur or setup (surprise surprise) but they did say that they think the problem is the sound of the derailleur resonating inside the chain stay. Interestingly the chain stay on this bike actually has an open end which I thought was a bit weird so the guy in the shop stuffed it full of some bits of pool noodle. Strange choice but I took it for a test ride and it is indeed quieter and almost acceptable. It still clunks on bigger hits but in general a lot of the clatter seems to have been significantly deadened and this is just with pool noodle. Imagine how much quieter it would be if the chain stay was filled with polyurethane foam? I think I will still get the bike sent up to Specialized to have a look at it because although it’s better, I’m not really happy with having pool noodle stuffed in my frame. Feels a bit cheap on a $12k NZD bike. Maybe Specialized should fill the chainstays with expanding foam from the factory and then they can give us a new set of chainstays to resolve the issue?

 

[The Jaisah]

I rode the bike 2 more times with the pool noodle stuffed inside the chain stays and it really is way nicer to ride. So nice that it actually makes me wonder if that's all they changed? If it is this simple, then I see the light at the end of the tunnel because it was much better and at a level that I would say is very acceptable. it still clunks on big drops but that's expected and the general chatter is significantly dulled. I just hope that specialized can come up with a more permanent solution than stuffing pool noodle in the chain stay haha. The bike went up to the Specialized headquarters in Christchurch on Wednesday and they said I should have it back by end of next week or the start of the week after. They said that Charlie Murrays mechanic is going to look at it which is pretty awesome to have such a skilled technician looking at my bike. Can't wait to get it back and see what they have to say about it.

 

[The Jaisah]

Update on my bike. I got it back from Specialized and they have determined that the sound is normal although they did say that they re-tightened the derailleur ensuring to be adequate tension on the detailer/chain while torquing to SRAM specs and they also indicated that the flip chip bolts were a bit loose which might have been adding a knocking sound. I rode it yesterday and it does sound better but it also still has the pool noodle foam stuffed into the chain stay so I don't know if the sound is fixed from what they did or just because the pool noodle is damping the sound sufficiently to make it acceptable. Either way it's good enough and I have wasted enough of my time and the shops time trying to fix this so I give up. It's good enough. I'll move on.