Hello,
Last night while doing race prep, i discovered three cracked side plates on my kmc 9-speed chain. Frustrated, i switched to getting my back up ride ready for race day to discover two cracked side plates on my Ultegra chain.
I replaced a kmc 9-speed chain last year due to a side plate cracking and thought I just wore the chain out
Clearly this isn’t a quality control issue and I am doing something wrong. What could be the cause of these cracked plates?
Which product are you using to clean the chain? Do you let them soak overnight? Could you describe your cleaning process?
are you soaking in simple green to clean your chain?
If you’re using something that’s water-based (like simple green) or even a harsh chemical to clean your chain (like mineral spirits), and you leave it to soak for a long time… We need more info to help you.
My understanding is that mineral spirits are OK, no significant hydron ions in solution to cause embrittlement. I’m just going off what I’ve read on the interwebs, so maybe wrong, but I’ve used mineral spirits for years with no issue.
Most water/citrus based solutions are a problem. Simple green is the poster child for embrittlement, makes quick work on steel.
I use them too, but there’s a difference between soaking overnight and soaking for 15-30 min with anything. I agree the water-based stuff is an issue. In the chain waxing thread, and talking to some of my friends locally who wax, there’s this feeling that more is better. You have people that soak chains in spirits overnight (which isn’t needed), and people who leave them out to dry for a day after alcohol baths (not only not needed but defeats one purpose of the alcohol bath), and end up with issues.
Prepping a new chain for waxing takes like 20-30 min. From removing the chain from the package to installing on your bike should take about 2 hours. Some people make it take like 4 days. 
Cleaning is with Simple Green. Never soaked, always used the Park Tool Chain Cleaner followed by a very thorough rinse with water. Ensured everything was extremely dry before applying MucOff dry lube very shortly after cleaning.
It’s very, very likely that’s what is causing the cracks. I’m honestly surprised it would cause damage with just a quick clean and complete rinse (and no soak), but again it’s known as one of the worst offenders for embrittlement. What are you rinsing with and what approach are you taking to ensure all simple green is removed? It’s really hard to get everything out of a chain even if you are using a proper rinse agent and agitating it well. I’d bet there is some residual simple green in the cracks/pins that is doing the damage. Personally, I’d just avoid the simple green going forward, it’s really bad stuff.
I followed the simple green with a very thorough rinse of water and even run the PT cleaner with just water.
The only time I’ve had issues with a chain is when I tried using simple green to clean while washing my bike. Never again.
All the water is doing is diluting (not removing) whatever you washed your chain with. A chain is more like a sponge than a solid surface. You can rinse out a sponge 20 times and you aren’t getting everything out of it, same with a chain. Best to clean the chain with something that doesn’t damage the chain, there will always be residual unless it’s an evaporative solvent or something that can be cooked off with heat (which are actually kind of the same thing).
UFO Clean is my favorite chain cleaner.
Yeah, you need to use a non-water-based degreaser. You’re not getting the internals as dry as you think you are anyway. There’s a reason why doing chain prep you want to use denatured (basically pure) alcohol, and that’s because it vaporizes at room temp, so you’re not leaving anything in there to get locked in by the wax.
Furthering the point about a chain being like a sponge, if you leave a prepped chain out overnight, it will take in water from the atmosphere - yes even here in dry San Diego - and then you lube or wax it and it sounds crunchy because you’re locking water in.
So get away from using water or water-based solvents at all on a bare chain, IMO. (Turns out apparently Simple Green is also corrosive if undiluted). I’ve used it on various non-metal components but anything with internals I wouldn’t use it (or personally water, but YMMV).
Ideally use Mineral Spirits to remove factory grease. Shake in a jar for 5-10 minutes. Repeat process until liquid is clear and absent of particles. Then, in a separate jar shake with Denatured Alcohol for 5 minutes (repeat twice) to remove the mineral spirits. Let air dry indoors in front of a fan for 1 hour, then wax/lube the chain. Both products can be purchased from most hardware stores (Home Depot). I just did this yesterday.
All, please keep in mind as you read this as I’m not discounting the advice above surrounding the Simple Green and embrittlement issue as I’ve read some of those same articles of late, but I’m not certain it’s 100% at fault here either…
I make that claim as prior to when I started waxing back in Mar/Apr 2023, for almost 3 years from Jan '20 (when my love of cycling was renewed) to early 2023, i followed much the SAME process as the OP as far as cleaning is concerned (based on advice I read on the net at the time surrounding chain cleaning/degreasing).
In those years for me, it was “on bike” degreasing with SG (straight/not diluted) using a park tool chain cleaner, running the chain for several rotations to make sure the chain was nice and sudsy and clean, and wiping it dry with microfiber cloth (no water or spirit rinses of any sort)… in all those cleanings and with several k’s of milage per chain, I never encountered any cracks or stress on the chain outside of normal wear.
Again, obviously not discounting above advice, but something for OP to keep in mind if/when they move away from SG onto something LESS VOLATILE to keep an eye open…
EDIT: @bobroxs, looking back at your OP, those chains look CRAZY DRY and/or no lube at all on them. Is it safe to assume that’s because you cleaned them all prior to taking the pictures for illustration purposes?
I started using simple green on a new SRAM flattop chain and it was stretched after 3000 miles. Thats when I started reading articles.
For routine maintenance, UFO Clean with 2 scrub brushes. Quick and easy.
Also works great for stripping factory grease on a new chain. Put a small amount in a glass jar, add chain, swirl around, let sit for 15 minutes or something like that, and just about done. Forgot the exact procedure, its on https://zerofrictioncycling.com.au
I’ve never noticed anything like this and I use simple green as the first step when cleaning ahead of waxing, will consider UFO next time.
Just to chime in as the devils advocate. I use simple green, soak overnight, followed by water rinse, dry, then add dry lube. Ill get a season out of a chain usually, dont get cracks like this. I use KMC chains.
The photos were taken after cleaning. I was drying it with a cloth before applying lube. Those chains in the photos are squeeky clean lol
