Only got 1500km on my the GX cassette before it started slipping under load

[Stevers]

I've had excellent results from my previous Sram drivetrains. My last moutainbike cassette did over 10000km, without slipping at all, when I used 3 GX chains rotated religiously between 700 and 800 km. My current gravel bike Red chain is at 13500km and cassette is at 14400 km with zero slipping, but I let the chain run just to .5 at about 11000 km and found that the cassette wouldn't take another chain, so Im just running it out.

My current Epic started slipping only when under heavy load only in the 3rd smallest gear at about 2500km. By that age it had an xx1 chain that had done 1600km.  I checked everything. Nothing was out of adjustment so I put up with it to just over 5000km.  And then I annoyingly replaced the cassette and xx1 chain and chainring. It's now done under 1500km and is slipping again on the same gear!!!  I checked everything, but this time took it to my local bike shop, where a lifelong bike mechanic checked it all, replaced the jockey pulleys and gave it a tweak. Its was fine for a while, but is slipping again.

Im finding it hard to understand it is giving problems so quickly when the  others have been treated exactly the same.

 

 

[Brighter-Lights]

There are some fake XX1 chains doing the rounds unfortunately. I bought one on the HUB recently for using on a wheelset I have with XD driver. (usual Shimano user)

Engagement of the quick link was the first indicator - almost no resistance instead of the usual snap sound when engaging, and the rollers were very loose for a new high end chain. Matt was very helpful in trying to resolve the issue, local importers confirmed that it was not from their stock. Seller didn't want to refund me and his seller account was suspended.

This may or may not be your problem, depending on where you sourced the XX1 chain from. Also check the B gap adjustment to make sure there's proper chain wrap around the small cogs.

This is exactly what I got:

https://www.instagram.com/reel/DGlyKUfzV7l/?igsh=NnBnb3JnZXVoeHdz

Edited July 26, 2025 by Brighter-Lights

[Ruben101]

17 minutes ago, Brighter-Lights said:

There are some fake XX1 chains doing the rounds unfortunately. I bought one on the HUB recently for using on a wheelset I have with XD driver. (usual Shimano user)

Engagement of the quick link was the first indicator - almost no resistance instead of the usual snap sound when engaging, and the rollers were very loose for a new high end chain. Matt was very helpful in trying to resolve the issue, local importers confirmed that it was not from their stock. Seller didn't want to refund me and was banned.

This may or may not be your problem, depending on where you sourced the XX1 chain from. Also check the B gap adjustment to make sure there's proper chain wrap around the small cogs.

This is exactly what I got:

https://www.instagram.com/reel/DGlyKUfzV7l/?igsh=NnBnb3JnZXVoeHdz

Does the banned user's name on bikehub end with com?

[Stevers]

Thanks. That’s useful information. I’m pretty sure I’ve had genuine chains. They’ve definitely been covered in normal manufacturing grease.  

[droo]

Do you measure your chains or just log mileage?

[Harryn]

Wow. I read this, and I just despair for us non technical shlumps.

[Stevers]

Yes I measure all of my chains.  I should have said in my post that both of the xx1 chains that are experiencing the slipping are basically measuring as new.  The only one that has gotten to .5 is the Red after about 11000 km. 
 

I should have said in the post that the slippage is pointing to excessive wear.    I just can’t reconcile that with my other experiences.  And hoping someone might come up with a possible other explanation. 

[mrcg]

So, just to understand: you have a GX cassette with XX1 chain and which chain ring? I'm thinking it could be the cassette. Generally I've found the GX does not to last very long (more or less what you've experienced now). Also, if you tend to ride most rides with overall more use of your 3rd lowest gear, this could wear quicker and hence the slippage.

I've opted for XX1 for cassette and chain (CSIXX chainring) - expensive but lasts much longer. 

[Stevers]

59 minutes ago, mrcg said:

So, just to understand: you have a GX cassette with XX1 chain and which chain ring? I'm thinking it could be the cassette. Generally I've found the GX does not to last very long (more or less what you've experienced now). Also, if you tend to ride most rides with overall more use of your 3rd lowest gear, this could wear quicker and hence the slippage.

I've opted for XX1 for cassette and chain (CSIXX chainring) - expensive but lasts much longer. 

Yes Im running GX cassette and XX1 chain where I'm having this problem.  Just that  previously gotten 11,300 km with my GX cassette with no problems at all

[Stevers]

1 minute ago, Stevers said:

Yes Im running GX cassette and XX1 chain where I'm having this problem.  Just that  previously gotten 11,300 km with my GX cassette with no problems at all

Running the standard sram 32 tooth GX chainring supplied withe the new bike.

[Michael S]

6 hours ago, Stevers said:

Running the standard sram 32 tooth GX chainring supplied withe the new bike.

Is this the same as with your previous setup where you got more milage?  

With a bigger chairing you'll sit higher up the cassette more often with the larger cogs spreading the load over more teeth than the smaller ones. Less effective load, less wear.

[Stevers]

Oh that’s something I hadn’t thought of.  To be honest I can’t remember what my previous MTB chain ring was.  Either 32 or 34.  Current one with problems is 32. 

[JoeMerida]

If there is too little tension on the chain it will cause slipping.

[thebob]

If the bike runs a UDH, make sure it hasn’t rotated backwards. After that verify b-tension and see if that helps

[Christie]

You take good care of yoir drive train, better than most, imo.

The casette is most likely to be your problem.

If it is only slipping in one gear, that sprocket may be from a faulty batch. My guess is that the factory in the East got the heat treatment (hardening) wrong.

This would be easy to test for - find a machine shop with a tool that can measure hardness. (Any repeatable measurement will do). All the sprockets should have similar hardness, except If the problem sprocket has lower hardness, it is a factory fault.

Hardness and strength are related for steel, as a general rule increased hardness means increased strength.

If you have data, you can try to convince the local agents to exchange it, 

[Stevers]

9 hours ago, thebob said:

If the bike runs a UDH, make sure it hasn’t rotated backwards. After that verify b-tension and see if that helps

Thanks.  Yes done both of those.