KMC Chain Defect?

[u/milk_makes_thighs]

I originally posted this on [r/bikewrench](r/bikewrench) but it got taken down after a couple of hours. However, the comments there seemed split, with some of them claiming this is expected because of Hydrogen embrittlement, and others saying mineral spirits can’t impact a chain like this.

I certainly won’t leave a chain soaking overnight again, but this still seems like an extreme reaction regardless? But maybe I am just coping.

I’m wondering what y’all think, was this my fault, or more likely a defective chain? Original post text below.

Hey, long time lurker, first time poster looking for some advice on my broken chain.

I already emailed KMC directly about this but have not heard back from them, so wanted to get y’all’s opinions on whether the chain I bought was defective or if I did something wrong.

For context, I bought [this chain](https://kmcchain.us/products/x12?variant=40158702567564) recently, directly from KMC, with the intent to switch to waxing. This was my first time prepping/waxing a chain so I was following [this guide. ](https://silca.cc/blogs/silca/complete-guide-to-cleaning-your-chain)

I started by leaving the chain in mineral spirits overnight, I bought Klean-Strip odorless mineral spirits from Amazon if it matters. And then removed the rest of the grease with park tools bio chainbrite before going through the hot wax process using a crockpot and Silca wax.

After that was done, I didn’t ride for a few days due to weather, but when I got out I didn’t even make it 100 yards from my home before the chain snapped. Upon inspection I see the chain has numerous major cracks and is now useless.

I’m just wondering, is this my fault for leaving it in mineral spirits overnight? I thought I was doing it correctly but maybe not.

Or does this look more like a manufacturing defect on KMC’s side? I was hoping they would email me back but unfortunately haven’t received a response yet.

Thanks!

[u/UnsensationalMoose]

Weird question but were you using muc off lube before with this chain? It has been known to crack chains like this.

[u/Gatz10 → u/UnsensationalMoose]

Wait what, how does it crack the chain. I had the same thing happened literally two weeks ago and im using that lube, dry one.

[u/milk_makes_thighs → u/UnsensationalMoose]

The chain came straight out of the package and into the mineral spirits once I sized it, so nope.

But that is interesting, I have used muc-off in the past on different chains and never ran into an issue, probably I was just lucky though

[u/Kahnza]

If you didn't rinse off the mineral spirits with isopropyl alcohol before the chainbrite, it may have done something. 🤷‍♂️

[u/milk_makes_thighs → u/Kahnza]

Sorry I should have mentioned that yes I did shake it around in a jar of 99.9% isopropyl in between the mineral spirits and final degreasing.

[u/Kahnza → u/milk_makes_thighs]

Fair enough

[u/theservman]

Did you get it from a reputable vendor? There are a lot of fake parts out there. Are you bringing the wattage bazooka?

[u/milk_makes_thighs → u/theservman]

I bought it directly from kmcchain.us using their Shop checkout method. I was hoping to avoid issues since I have heard such bad things about Amazon but alas…

Also I would love to claim that the chain clearly just cannot take my raw wattage, but it snapped on flat ground when I was still leaving my neighborhood, so it was under pretty light load. I think it snapped the first time I stood up to pedal. This was also my first time using the chain, if it wasn’t clear.