Chain quick-connector failure?
 

I recently had a KMC Missing Link blow up on me and it almost left me stranded but I happened to have the old SM-CN79 that came with my bike originally (two chains ago) in my seat pack. That at least got me home.

On the way home from work today, I stopped and picked up a new Missing Link and also a new Dura Ace Chain. I noticed the Shimano quick link isn't really available anymore but anybody else experienced total failure of the Missing Link?

I'm considering putting my chain back together with the normal Shimano connecting pins.

I've used Superlinks, Powerlinks/Powerlocks, & Missing Links, and never had a failure of any of them.

^ ^ ^ Same here.

Link failures are very rare, but they do happen. Without a damaged link to examine it's impossible to say why or how. OTOH, chains also break not at the connector. If you figure that connectors are about 1 out of 56 links on a typical chain, you'd expect link failures to account for about 2% of all failures, all other things being equal.

It is a rare failure but it can happen... recall that some years ago SRAM had some issues with their quick links failing but they rectified this very quickly and their quick link was improved.

My only link failure was a SRAM at this period and when it happened i was ascending a very rocky climb and it could have very well been a rock spit into the drivetrain that found the quick link which did not break, but opened and I lost my chain. Was lucky to have found the missing links and be able to ride home.

I've had failures on SRAM PowerLinks (but not PowerLocks), KMC and Wipperman/Connex. I think their weakness is partly that they're designed (with the exception of PowerLock) to come apart when compressed end-wise, although a squeeze from the sides usually helps. Chains are normally under tension, right? So it shouldn't be a problem that they might disconnect when compressed endwise... right? Well, reality is cruel, and sometimes arranges for chains to be compressed endwise in one fashion or another. Chainsuck is a prime example.

Anyway, if I had a dollar for every masterlink I've personally had come unplugged in normal use, I could probably afford a gallon of chocolate milk :thumb: If you have a Shimano chain, then I'd go ahead and use the Shimano chain pins, and do it as Shimano instructs: through the rear hole of an outer link on the underside stretch of chain.

Yes, unfortunately connecting links are not indestructible.

They are in fact the weakest link as is created by any connection type used - Shimano pins included.

I broke the SRAM link recently, While generally a spinner and easy on my drive train, I recently had 9 speed chain jam under loaded cross chaining shift (my bad) between my old bio pace crank . (bad set up bad shifting) The weakest link broke. Other than that I have had many thousands of miles out of these SRAM links and am a real fan and will continue to buy and use.

.. given your experience, buy 2 , next time..

That's like a bet that lightning will strike twice in the same place.

I'll cover that bet.

Contrary to the popular expression, not only does lightning strike twice in the same place, it strikes hundreds (thousands) of times in the same places. Among the most frequently struck places is NY's Empire State Building, along with many mountain tops, and other high places. What makes someplace a good place for a lightning strike, makes it a good place for a repeat.

So, the old used Shimano quick connector didn't cause any problems today. I'm wondering if part of the issue was that the MissingLink 10R was not the locking one? Perhaps it rattled loose during the very fast descent (45-55mph for a couple miles) I had done earlier in the ride... When it started skipping through the derailleur on a short climb later, I looked down and noticed there was only one plate and both pins remaining... Not sure how the pin separated from the other plate.

I haven't had a chance (read: haven't taken the time) to put the chain together with an actual shimano pin so the quick connector remains for now. I'm away from home and don't have the extra links handy and this chain is relatively new so i don't want to just put the brand new chain on.

(for a guy who works in a shop on saturdays, i sure take crappy care of my own bikes)

I had 2 SRAM links fail on me. The first time was on my commuter and I pedaled my chain right off my bike in an intersection. I was able to hop off and grab it & run to the sidewalk.

The second time was on my road bike just 3 weeks later, in traffic, and when a light turned green I laid all my weight on a pedal the chain popped and I went over the bars. Luckily the cars were still just creeping and I wasn't run over.

I still use the SRAM chains but gave up on the quick links and put them together with a chain tool, the old fashioned way. I'm still a little gun-shy of really standing on my pedals to accelerate or climb.

FBinNY, I realize that lightning re-strikes, but I'm talking about striking in an unlikely place, metaphorically speaking. Would you expect two quick links to fail for one person? I wouldn't, unless they're put on wrong somehow.

And I'll still take that bet. I've seen people put things together the wrong way, break them, get a replacement, put the replacement together the wrong way, and break that.

Also, it's not like they're expensive, or heavy. The OP carries a seat pack, he's probably got room for a spare quick link! And they can be used to fix a chain that breaks somewhere else.

I keep one or two spare master links inside my Rema patch-kit box for quick roadside repairs. There's no denying the convenience factor. Shimano's replacement pins are actually pretty convenient too, although removing a damaged link and pinning the remaining chain back together does leave it shorter, whereas the master link maintains the same chain length if it's taking the place of one damaged outer link.