SRAM Eagle Cracked Chain Plates

[Grease_Monkey]

And here..

 

https://www.mtbr.com/product/drivetrain/chain/sram/gx-eagle-12-sp.html

 

This is clearly a massive problem with these chains. I suggest if you have a GX 12 speed chain on you bike you keep a close eye on it

Another hubber posted on a thread yesterday about his chain doing the same. Not as many links as yours, but the same issue.

 

Personally I wouldn't take money out of my wallet again for one.

[snutkin@gmail.com]

 

Ok, let me explain…. 

 

I am not disputing that a chain tool measures chain stretch as a percentage of overall chain length, and I am not disputing that it is 0,25%, 0.5%, and 0,75%.

 

Some context…. A while back I was going through GX Eagle chains very quickly, and some people on the hub were making big claims about the life span of XX1 chains. I decided to try that, and for curiosity’s sake I wanted to measure how the chain was stretching accurately. So here is what I did, which should explain my initial post a bit better.

 

I replace my chains at 0.75% - that is my “allowable” amount of stretch. To measure I take a vernier calliper, and measure the length from the inside of a roller to the inside of another roller with 10 links in between. For the sake of my explanation let’s say that measurement is 100mm on a new and unused chain. I then took a chain at 0,75% wear and took the same measurement, let’s say for this explanation that this measurement was 110mm, thus giving me an allowable stretch of 10mm. So, if the measurement reads 102,5mm that means I am at 25% of allowable stretch. When it gets to 110mm I am at 100% of allowable stretch, and it is time to replace. Again, I am just using these numbers to explain the concept.

 

As I used my new XX1 chain I take this measurement often, after a considerable amount of km, I am not even at 25% of allowable stretch.

 

Hopefully that clears it up?

 

On the stretch/wear thing. Chains can wear (degradation of the material) and stretch. Bicycle chains generally speaking stretch before the material degrades, and that’s why we measure stretch.

 

Okes really need to relax, this isn’t a foreign policy or religious rights debate. We’re talking about chains.

 

 

Thank you. Understood. Please allow me to withdraw my previous comments.

[boesman88]

This is an update on the outcome of my Snap-Crackle-and-Pop ordeal.

 

 

 

It appears that the problem lies with the GX cassette and NOT the chain.  The cassette has a manufacturers defect - certainly the model I had (2018 stock).  When the chain is running on the 18 tooth cog, there are two adjacent teeth on the 16t cog that interferes with the chain plates running over the 18t ever so slightly.  The interference is caused by the shape of these two teeth and its (mis)alignment with regards to the others, placing it slightly closer to the adjacent cog on a cassette that already has very tight tolerances. This puts a force perpendicular to the chain while under normal pedaling tension which explains the occasional clicking sound at is catches the chain plates. (see my attempt at a picture to explain this)  Over time this causes the chain plates to fail under this undue stress resulting in snap, crackle and pop's.

 

The above is of course my synopsis of the problem - having read up a lot about alignment issues on the GX on other forums, checking out videos of the two mis-aligned teeth and noticing way excessive wear on the said two teeth on my own cassette.  This, plus 1. the agents requesting the chain AND the cassette for inspection (which was a bit puzzling at first), 2. the agents' original response which downplayed the issue from the get go and suggested wear and tear as the cause and 3. upon enquiring about the outcome of their assessment, I was informed by the workshop manager that SRAM was 'not happy with the middle part of the cassette'. 

 

Outcome - full replacement under warrantee. expecting the new bits to arrive tomorrow. 

 

Not quite sure what to make of this whole thing.  I still think SRAM is a great product but it does feel that this defect is being hidden from the general public, hoping people wont notice.  Had I simply replaced my chain with an XX1 without getting to the bottom of it, I would have wasted that money too.  

 

If you are now worried about your own setup and that your warrantee might have expired - some people (I do not recommend this btw) have successfully modified their cassette's by filing the two teeth back ever so slightly (using dremmel or the like) to avoid interference with the chain running on the 18t. proceed with caution please when considering this as its an expensive piece of metal to test your diy skills.   

 

Good luck

Edited June 11, 2020 by boesman88

[madmarc]

Thanks for the feedback and explanation - interesting ! - I will be checking my GX setup for this 

[Grease_Monkey]

This is an update on the outcome of my Snap-Crackle-and-Pop ordeal.

 

 

 

It appears that the problem lies with the GX cassette and NOT the chain. The cassette has a manufacturers defect - certainly the model I had (2018 stock). When the chain is running on the 18 tooth cog, there are two adjacent teeth on the 16t cog that interferes with the chain plates running over the 18t ever so slightly. The interference is caused by the shape of these two teeth and its (mis)alignment with regards to the others, placing it slightly closer to the adjacent cog on a cassette that already has very tight tolerances. This puts a force perpendicular to the chain while under normal pedaling tension which explains the occasional clicking sound at is catches the chain plates. (see my attempt at a picture to explain this) Over time this causes the chain plates to fail under this undue stress resulting in snap, crackle and pop's.

 

The above is of course my synopsis of the problem - having read up a lot about alignment issues on the GX on other forums, checking out videos of the two mis-aligned teeth and noticing way excessive wear on the said two teeth on my own cassette. This, plus 1. the agents requesting the chain AND the cassette for inspection (which was a bit puzzling at first), 2. the agents' original response which downplayed the issue from the get go and suggested wear and tear as the cause and 3. upon enquiring about the outcome of their assessment, I was informed by the workshop manager that SRAM was 'not happy with the middle part of the cassette'.

 

Outcome - full replacement under warrantee. expecting the new bits to arrive tomorrow.

 

Not quite sure what to make of this whole thing. I still think SRAM is a great product but it does feel that this defect is being hidden from the general public, hoping people wont notice. Had I simply replaced my chain with an XX1 without getting to the bottom of it, I would have wasted that money too.

 

If you are now worried about your own setup and that your warrantee might have expired - some people (I do not recommend this btw) have successfully modified their cassette's by filing the two teeth back ever so slightly (using dremmel or the like) to avoid interference with the chain running on the 18t. proceed with caution please when considering this as its an expensive piece of metal to test your diy skills.

 

Good luck

First time I have heard of this. That is a pretty massive oversight from Sram. I wonder if it is just a few batches, or all of them. Will check on mine tonight (but I'm a couple thousand km in without that issue), hopefully not the case.

[droo]

This is an update on the outcome of my Snap-Crackle-and-Pop ordeal.

 

 

 

It appears that the problem lies with the GX cassette and NOT the chain.  The cassette has a manufacturers defect - certainly the model I had (2018 stock).  When the chain is running on the 18 tooth cog, there are two adjacent teeth on the 16t cog that interferes with the chain plates running over the 18t ever so slightly.  The interference is caused by the shape of these two teeth and its (mis)alignment with regards to the others, placing it slightly closer to the adjacent cog on a cassette that already has very tight tolerances. This puts a force perpendicular to the chain while under normal pedaling tension which explains the occasional clicking sound at is catches the chain plates. (see my attempt at a picture to explain this)  Over time this causes the chain plates to fail under this undue stress resulting in snap, crackle and pop's.

 

The above is of course my synopsis of the problem - having read up a lot about alignment issues on the GX on other forums, checking out videos of the two mis-aligned teeth and noticing way excessive wear on the said two teeth on my own cassette.  This, plus 1. the agents requesting the chain AND the cassette for inspection (which was a bit puzzling at first), 2. the agents' original response which downplayed the issue from the get go and suggested wear and tear as the cause and 3. upon enquiring about the outcome of their assessment, I was informed by the workshop manager that SRAM was 'not happy with the middle part of the cassette'. 

 

Outcome - full replacement under warrantee. expecting the new bits to arrive tomorrow. 

 

Not quite sure what to make of this whole thing.  I still think SRAM is a great product but it does feel that this defect is being hidden from the general public, hoping people wont notice.  Had I simply replaced my chain with an XX1 without getting to the bottom of it, I would have wasted that money too.  

 

If you are now worried about your own setup and that your warrantee might have expired - some people (I do not recommend this btw) have successfully modified their cassette's by filing the two teeth back ever so slightly (using dremmel or the like) to avoid interference with the chain running on the 18t. proceed with caution please when considering this as its an expensive piece of metal to test your diy skills.   

 

Good luck

 

Known among mechanics as a 4th gear ticker, and it's a warranty replacement on the cassette.

 

I've never heard of it taking a chain with it, so this is pretty interesting.

 

On the stretch / wear / elongate thing - it's semantics. If you call it stretching we know what you mean.

[boesman88]

Known among mechanics as a 4th gear ticker, and it's a warranty replacement on the cassette.

 

I've never heard of it taking a chain with it, so this is pretty interesting.

 

On the stretch / wear / elongate thing - it's semantics. If you call it stretching we know what you mean.

 

You should have said this 7 pages ago - that would have saved me hours of investigation... :-)

 

On the chain stretch wear thing - that's a separate debate it seems and I am with you on this one, if its stretched/worn/elongated etc, it means its useful life is running out like with all mechanical things and soon to be replaced.  

[DieselnDust]

Known among mechanics as a 4th gear ticker, and it's a warranty replacement on the cassette.

 

I've never heard of it taking a chain with it, so this is pretty interesting.

 

On the stretch / wear / elongate thing - it's semantics. If you call it stretching we know what you mean.

 

 

 

Yeah I figured those cassettes were out of circulation already as this was a problem on the first batches released 2 years ago. I guess with lots of 2018 bikes still sitting on shops floors its going to be a while before its completely out of the market.

 

Boesman, SRAM is very good with warranty if its a known issue. It does take a bit of time since the global warranty centre is in Australia so the time difference makes it a bit of a challenge to get same day turn around. Glad you're sorted. The revised cassette won't give you issues and your XX1 chain is safe

[boesman88]

Yeah I figured those cassettes were out of circulation already as this was a problem on the first batches released 2 years ago. I guess with lots of 2018 bikes still sitting on shops floors its going to be a while before its completely out of the market.

 

Boesman, SRAM is very good with warranty if its a known issue. It does take a bit of time since the global warranty centre is in Australia so the time difference makes it a bit of a challenge to get same day turn around. Glad you're sorted. The revised cassette won't give you issues and your XX1 chain is safe

 

I hear you.  Rationally speaking you are probably right.  Right now though I am wondering what I would get for the complete SRAM GX groupset incl brakes, cranks, drive train, Syncros 3.0 29" wheels the works. The chain and cassette is brand new    

[DieselnDust]

I hear you.  Rationally speaking you are probably right.  Right now though I am wondering what I would get for the complete SRAM GX groupset incl brakes, cranks, drive train, Syncros 3.0 29" wheels the works. The chain and cassette is brand new    

 

 

You'll get more hits if you advertise it "as better than new. All warranty issues sorted"

[boesman88]

You'll get more hits if you advertise it "as better than new. All warranty issues sorted"

 

lol you are right.  

[Hairy]

The SRAM Chains are made in Taiwan and I suspect by KMC. Used to be SACHS back in the day but most chains are made in Taiwan or Mainland China. I've never seen a failure that so consistent in a chain before so I strongly suspect its just a bad batch that crept through. In production the stamping tools only get checked on a frequency basis and that's informed by retained plates that get measured with a go no-go gauge. Those plates are merely samples of many thousands of plates that are stamped per minute so its easy to see how the worn die would not be caught early. Generally the system works and the fact that you don't see this type of failure often bares this out. 

 

I would advise you get the XX1 chain though. It'll last you up to 6000km in my experience.

 

 

Get the XX1 

its 30% more expensive and it'll last 4 times longer

its like a duracell of chains

From a technical standpoint, why would the more expensive chains last longer that the entry level chains please?

[Hairy]

found this now ... https://cyclingtips.com/2019/12/the-best-bicycle-chain-durability-and-efficiency-tested/#most-durable-12-speed

[snutkin@gmail.com]

Oh boy. Now that is interesting. I have an occasional ticking sound too which I have never been able to identify. Time to take a good look at things.

[droo]

You should have said this 7 pages ago - that would have saved me hours of investigation... :-)

 

On the chain stretch wear thing - that's a separate debate it seems and I am with you on this one, if its stretched/worn/elongated etc, it means its useful life is running out like with all mechanical things and soon to be replaced.  

 

If you'd said it was making a funny noise in the 18t...

 

Also, what's a Bikehub thread without handbags at 10 paces? Especially if it's a semantic argument.

[ChrisF]

VERY interesting ....

 

Did a 1x12 upgrade to the TREK in March 2018 .... Went back 3 or 4 times to the LBS with a "ticking sound" ..... eventually was told two teeth were "bent", they litterally bent the teeth "back", and the ticking sound was gone .....

 

One of the top workshops in Durbanville ....

 

Now I am wondering at what point SRAM made this recall known to the industry ....

 

 

 

O-well, it was not making a ticking sound when I sold it ... so maybe "better than new" did apply ?    

 

 

PS - the 2019 Scott never had this ticking sound .... it had its own set of issues with ultra fine tuning ....

Edited June 11, 2020 by ChrisF