Not too long ago, my chain broke just as I was beginning my ride. The outer plates on one of the links had given up, bending outward in dramatic fashion.
This was a first for me.
Driving a joining pin into a Shimano CN-HG54 10-speed chain using a multi-tool’s chain breaker.
These days, there are many, many resources online that can help you with chain repair and get you going, assuming you have the right tools and supplies on hand. Specifically, you’ll need a multi-tool with a chain breaker, plus either a spare joining pin (for Shimano or Campagnolo chains) or a master link (for SRAM, KMC, Taya and Wippermann chains).
I carry these in my saddlebag, and I know how to use them, so the only inconvenience for me was leaving about ten minutes later than planned…plus dirty, greasy fingers from handling the chain. My KMC 10-speed master links had some rust on them, but were still very usable, and so I replaced the busted outer plates with one of the master links and made it to my destination safely.
That should have been the end of it. Or was it?
My trusty Park Tool CC-3.2 chain checker, here indicating that the chain has not yet worn down 0.75%. A cheap, must-have tool.
A few days later, I took out my Park Tool CC-3.2 chain checker and used it on the chain. The 0.5% end fell straight through the links, indicating 0.5% wear. The 0.75% end didn’t, though. Okay, I told myself, I should stay on the conservative side and look for a replacement chain, but no hurries.
I took a closer look at the chain though and found this.
Apparently there were more links on my chain with broken outer plates. These were ticking time bombs. There’s no way of telling when these outer plates would finally let go and lead to another chain failure event.
I replaced the chain straight away.
A pair of outer plates and chain rivets from my KMC X10EL chain. Note the broken outer plate. There were more of these.
Park Tool recently released a few videos on its YouTube channel on chains, sizing, repair, and replacement procedures. It stressed that in case of chain breakage, you could always repair it the same way I did. However, that broken chain must be replaced as soon as possible.
Well, the broken outer plates all over my repaired chain are one possible reason why. Even at 0.5% wear, which for 10-speed chains indicates a bit of life left, my chain clearly shouldn’t be ridden any longer. These broken links are what you should take particular notice of on your chain – we all know what they say about it only being as strong as its weakest link.
Always keep a spare chain at home to match your drivetrain, at least as long as your current chain’s length. As long as the packaging is unopened, you won’t need to worry about it rusting or corroding, as it comes coated from the factory in a grease-like lubricant for storage.
the accidental randonneur 