Cleaning my bike off I noticed this. I haven’t hit anything while riding and I’m pretty good about maintenance. As far as I can tell, nothing in my drivetrain is misaligned and I don’t shift under stress. The chain is broken in 3 places, though. Chain is the shimano XT CN-M8100 12 speed. I use muc off drivetrain cleaner on it and muc-off dry lube. The r/mtb sub had some good inputs but then my post got removed.
by Solid_Science4514
22 Comments
Fake chain probably, make sure you buy from a reputable seller
Where did you buy the chain? There’s a LOT of fake chains going around if you purchased it online. This kind of breakage is not typical at all.
I know it’s been posted already by others but you mostly have a fake chain you bought on Amazon or something, muc-off products are good quality & wouldn’t do this to your chain in my opinion…
If it’s not a fake chain, maybe you can always send it to the company so they can run some lab tests on it?
That would be cool to know about…
Are you on an ebike by chance?
How big are your quads?
Too much power. Humble brag.
Op got 3k watts on tap
Could be unrelated but I stopped using mucoff lube as the wear rate on my xt chain was horrendous. Swapping to peatys lube, the chain lasts twice as long. This is on my ebike.
Looks like the chain has been under stress and the link has failed. On a non broken side how much wear is there?
Either just buy a new one and try a different lube, or try and warranty it….
Should have bought it from a reputable place like Jensen. (Kidding, I read the replies!)
Brand new chain? I’d send them an email. Handful of rides? I’d still reach out. You didn’t strip it or anything?
That’s terrifying. All those cracks, but the chain didn’t break completely?
Do you degrease with simple green and let the chain sit in the solution overnight? I have heard it supposedly weakens the metal but don’t know if it’s true or not.
I’m going to go against the grain and wonder about your chainring and cassette. Is your drivetrain aligned well? Are you shifting under load a ton and powering through “crunchy” sounds?
happened to my Kenevo SL chain… the one that came stock
mine was SRAM but this looks Shimano
Mic off dry lube strikes again.
There are HEAPS of this exact post on reddit and it’s almost always a chain that’s had mic off dry (yellow) lube.
This happened to me too. OEM chain. I’m usually gentle on my drive chain and the rest of it has lasted several seasons.
Happened to my stock SRAM NX chain. I switched to a SRAM X01 chain two years ago and haven’t had a single crack.
So, I have had this happen on 7100 and 8100 chains since I started using the muc-off degreaser. It had not happened before with the stuff I was using prior, while using muc-off chain lube. But after switching it started on my bikes including one with a gx drivetrain. It happened on my partners bikes. I won’t say I’m 100% sure its the de-greaser, however I will say the evidence that I have seen would point me in that direction….
Nah that’s definitely from you shifting under stress because this is exactly how my chain looked like before it exploded too and I was shifting under stress when I was riding unknown trails and it would suddenly turn into a punchy climb while I was on the highest gear
I’ve had SRAM X01 chains on my Hightower break at two side plates at once with a link or two in between them, just like yours, except I discovered it while sitting and pushing the wrong gear up a short upslope. I felt the huge pressure in my feet and thought “I hope the chain doesn’t break” and boom, it broke within milliseconds of that. Go figure. I do have very big quads and weigh 250lbs. I never broke chains until I went to 11speed/12speed 1x setups. I think the high misalignment and thin sideplates make them weaker than the chains I rode since the 80’s and 90’s when I even used to be able to stand up and really put in power. I don’t shift under power, and the chains always are OK when measured with a chain checker tool. I sure do miss standing up on a bike and pedaling. I’d buy a 2x 9speed setup if I could.
I broke a chain like this once when I was young and strong. I was tearing through the woods on my xc bike and I managed to catch a small stump right so it hit my pedal and not my shoe. It slammed the crank hard forward, and I think it was enough to crack my old sram drilled 990 chain.
So just asking is it upside down. Because i thought the Shimano was supposed to be reasonable not upside down. This increases wear, but I’m just a novice so i could be wrong.
I did this to my first XT 12Spd Chain – regular ol’ pedal bike.
Replaced it with another XT, and the chain wore out before I had any cracks.
3-4 Chains Later, I’ve not had the cracking issue repeat itself.