droo Posted June 11, 2020 Posted June 11, 2020 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. DieselnDust, Hairy, ChrisF and 1 other 4
boesman88 Posted June 11, 2020 Author Posted June 11, 2020 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 Posted June 11, 2020 Posted June 11, 2020 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 Posted June 11, 2020 Author Posted June 11, 2020 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 and Hairy 2
DieselnDust Posted June 11, 2020 Posted June 11, 2020 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" Hairy 1
boesman88 Posted June 11, 2020 Author Posted June 11, 2020 You'll get more hits if you advertise it "as better than new. All warranty issues sorted" lol you are right.
Hairy Posted June 11, 2020 Posted June 11, 2020 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 longerits like a duracell of chainsFrom a technical standpoint, why would the more expensive chains last longer that the entry level chains please?
Hairy Posted June 11, 2020 Posted June 11, 2020 found this now ... https://cyclingtips.com/2019/12/the-best-bicycle-chain-durability-and-efficiency-tested/#most-durable-12-speed DieselnDust 1
snutkin@gmail.com Posted June 11, 2020 Posted June 11, 2020 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 Posted June 11, 2020 Posted June 11, 2020 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. Rocket-Boy, Hairy, ChrisF and 1 other 4
ChrisF Posted June 11, 2020 Posted June 11, 2020 (edited) 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 Hairy, Skylark and DieselnDust 3
MudLark Posted June 11, 2020 Posted June 11, 2020 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 .... Chris, exactly the same thing here. 2018 Trek with SRAM GX… It goes tick, tick, tick when pedalling in a high gear, particularly going uphill. Only some of the time, not always. Has driven me nearly nuts at times. Now I am wondering… DieselnDust 1
ChrisF Posted June 11, 2020 Posted June 11, 2020 Chris, exactly the same thing here. 2018 Trek with SRAM GX… It goes tick, tick, tick when pedalling in a high gear, particularly going uphill. Only some of the time, not always. Has driven me nearly nuts at times. Now I am wondering… seems a link-by-link inspection is to be done .....
DieselnDust Posted June 11, 2020 Posted June 11, 2020 seems a link-by-link inspection is to be done ..... No just check the 16, 18 and 21 tooth sprockets. The problem was mostly on the 18T on the GX cassette. Its a stamped part. SRAM traced the issue to a tooling issue and corrected the tool. High probability of 2018 MY GX equipped bike having the problem cassette. ChrisF 1
MudLark Posted June 11, 2020 Posted June 11, 2020 No just check the 16, 18 and 21 tooth sprockets. The problem was mostly on the 18T on the GX cassette. Its a stamped part. SRAM traced the issue to a tooling issue and corrected the tool. High probability of 2018 MY GX equipped bike having the problem cassette. Thanks will check but not sure if my eye is sufficiently trained… Unless it is fairly obvious. Will pull the wheel and have a look. Normally I lube my chains link by link (more accurately roller by roller) and haven't picked up anything but wasn't really looking at the chain plates. I think I will take a torch and run my eye over them anyway. The last thing I want to do is have a chain snap when I'm standing up on the pedals – just not worth the risk. DieselnDust and Super Sywurm 2
MudLark Posted June 11, 2020 Posted June 11, 2020 Checked – went over the links one by one with the torch, slow rotation of the crank. Don't pick up anything. Check the cassette, again slow rotation checking the teeth by eye using a torch – again, don't pick up anything. Given that it is intermittent and seems to have gone away now, might be something else. Will keep my ears open… DieselnDust 1
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