I was going to do some sprint intervals today, but during the first interval, the chain immediately started to skip very badly. when i stopped to check, I found one of the links had completely ceased up. there appeared to be a metal shard stuck in there, causing it to be ceased up. I have no idea where the metal shard came from. I broke the chain and put it back together to get it out, and only got it to be partially unstuck, such that I was still able to finish my 30 mile ride that way. By the time I got home to diagnose it, the chain was completely fine, except for the fact that I can no longer locate the link with the broken seal in order to replace it with a quick link. (next time I use that chain, I'll carry a spare quick link)

so what do you think happened here?

do you think i can safely use the shimano chain with one of the links with a broken seal?

The more speeds we've gotten, the thinner the sideplates have become. The thinner the sideplates are, the harder they have to be to last long enough. The harder they are, the more brittle they become. The more brittle they become the more likely they are to crack during assembly.
If it's only a partial crack, it can take some time before the piece flake off.

What seal are you talking about?

i don't know if the metal shard came from the chain.

the seal i'm talking about is the crimped part of the chain push pin that keeps the pin locked in the chain. my understanding is that without that seal, the chain risks breakage

How many speeds are you running on your bike?

I've re-used 9s pins without problems.
I haven't run 10s (yet).
And, am not sure I'd re-use 11s pins. I should buy some replacement pins.

I don't carry a file with me, but on installing the chains, sometimes I'll mark the re-connected link with small file marks on the outside edges of the two surrounding links.

The word you want is "seized" not ceased.
My wife does the same thing, drives me nuts.

No. Losing chain tension standing with your weight forward often leads to a crash which you don't want to risk for a $25 chain

Modern chains rely on peened pins to stay together, and cutting them removes that.

I keep three master links plus the left overs from a new chain in my saddle bag, which is enough to get back to a full-length chain from the oddest failure I've ever experienced - my chain over-shifted past the big ring, went back on with two loops, and bent a link at each loop.

I occasionally broke (as in side plates opening by themselves) 9 speed Campagnolo chains which are still constructed conventionally with pins going all the way through full-thickness side plates instead of being peened over in recesses in spite of not shifting under load.

That's never happened in over 23,000 miles since I switched to 10 cogs with flush-riveted chains in 2012.

I would not trust that chain, myself. I would try really hard to find the pushed-in pin and replace it with a master link, or failing that replace the chain.

This is exactly my approach, I keep them in a little bag with a Park CT-5 Mini Chain Brute. The size and weight are minimal but the savings in time and aggravation can be big. A couple of minutes' work and you are back on your way, rather than standing there scratching you head and wondering "WTF am I going to do now?"

Yes, the concern of an outer side plate prying off the pin if the peening of the pin's end is damaged is real. Adding to the simple description is that this usually happens when the chain is under a large amount of force. (I know of a guy who broke his pelvic bone when his chain broke). In a shop setting if we couldn't ID the pin and then replace it, the link, properly we would be negligent if we didn't replace the chain.


BTW a very common reason that chains have these problems, links prying off plates and gauges causing tight links, is because of shifting when also powering the pedals a lot. We call this "jam shifting". Modern chain and tooth designs make shifting far more possible in situations that only 20 years ago were considered abusive. That we can shift while standing/climbing up a steep incline or when accelerating from a stop doesn't mean it's the best thing to do or won't result in harm to the chain. Andy.

I started carrying a chain tool last summer and twice it helped other cyclists resume their rides - first time I broke a woman's jammed chained, removed bent links and joined it back together.
Second time I let a man in similar fix use it to make his bike rideable again. No substitute for a chain tool.

I thought he meant it broke.....

Did you push out the factory connector pin? That's a no-no. You should only break the other std. pins.

His heart seized and therefore he ceased.

that's what i figured. the problem happened right after i started my first sprint interval. funny, I've been riding for a long time, and by now, it's become muscle memory to only shift at the 12'/6' pedal positions during a sprint.

I'm gonna have a seizure salad with dinner....

Since it's spelled correctly in the thread title, I'm thinking this might be an "autocorrect" issue.

Ouija Board may have your answer.. Why.

Id Just Replace the chain & cassette and get on with your exercise ambitions.

Spring Major Tuneup, beat the Rush..