cave12man

Had just finished putting on a new set on Conti's and was all geared up for a ride when my chain broke literally 100 ft into the ride. So, I brought her back in, removed a link, and tried to head back out. Bam, chain broke again. Literally didn't even make it 5 ft. Took it out for about two weeks ago and everything was fine. Bought and installed the Reynolds R4's recently but haven't been able to test them, tonight was going to be the first time out. I'm baffled at what could have made the chain snap like that. The Reynolds did require a 10sp spacer for the hub, but that shouldn't have hurt anything. Everything ran smoothly until I tried to actually use the damn thing.

I'm a bit perplexed. Anyone have anything similar happen over the years? I'm running out of things to check and I don't want to buy another chain only for it to happen again.

FBinNY 

I doubt you know for sure, but it probably broke at your splice.

Poor connections are far and away the most common cause of derailleur chain failure.

However, if it helps you, there are two main types of chain breakage.

1- pin/plate connection failure. This is caused by the plate being worked beyond the end of the pin, and you'll recognize it by an intact plate with the pin out, and the opposite side plate bent with the pin still attached.

2- broken plate. Almost always the outer, and you'll see the broken plate (the opposite side may be OK or not), with the fracture running through the hole.

The plates can be defective and the victim of poor heat treating, an undersized hole so the stress of the pin is too great, or other manufacturing issue. Or the plate can become brittle and fail because of chemical attack, usually by chlorides in chain wash liquid or road salt.

Plate failure is rarely isolated, and if a plate cracked at a pin, odds are you'll find other plates showing stress cracks at pin holes and ready to crack at a the slightest provocation.

If you had plate failure, the ONLY remedy is to replace the chain. However connection failures can be repaired by properly splicing in a link or two using a closure pin or connecting link.

2lo8

The fact that you're just popping out links like it's nothing, are you using the dedicated joining pins or links, or are you just rejoining with the pins you pushed out?

cave12man

Pretty sure it a pin/plate since the plate was all deformed when I pulled the chain out.

The chain (Ultegra) was put on by someone who I bought the bike from. I've since made bunch of changes to it but never messed with the chain. He said it was a brand new chain when put it on, and seemed to know what he was doing. I've only ever really dealt with quick links so maybe there was something I missed with the Ultegra chain? It rode fine before I switched out the wheels though.

Maelochs

I know I have "fixed" a chain but hurried too much and didn't check every link ... and then "fixed" link was too tight and caused the drive to stutter. if I had kept riding it would likely have snapped there again. otherwise .. when I am mystified I blame the aliens. I can tell by who laughs and who looks nervous which people I can count on later ...


when the zombies attack.

2lo8

So did you use a quick link, a Shimano snap-off joining pin or what?

FBinNY 

OK, so it was a closure failure, probably caused by the pin not being aligned when pressed and distorting the plate before sliding in to the hole (if it even did).

That's one failure accounted for, what about the other. I assume the second closure was yours, so unless you got the bike with a chain spliced together from 2 parts (two closures) then you need to check the mirror for the cause of the 2nd failure.

andr0id

You can't just push out and push back in a pin on any Shimano 10 or 11 speed chain and probably not on other ones either, but I can't remember that far back.

You either use the special pin that comes with the new chain and break off the extra bit when done OR you use a SmartLink or other type of master link from KMC, SRAM or Wipperman.

AlexCyclistRoch

I believe ALL Shimano chains REQUIRE that you use a dedicated snap-off pin when rejoining their chains. It's been that way for 20+ years.

cave12man

Thanks guys. I've honestly never had a road chain break on me. Once on my mountain bike but I had a quick link with me.

FBinNY 

Yep.

EVERY Shimano chain produced after the advent of Hyperglide and requires closing with a special pin.

Hyperglide and the other gated shifting systems that followed (all brands) tends to force outer plates outward when shifted under any kind of load. So the pins need to be peened over the plates to resist that. When you push a pin out, you shear off the pin, and there's no practical way to fix that.

Homebrew01

Use a quick type link. Problem solved. Don't let that guy work on your bike.

BikingGrad80

I pretty much always use a SRAM of KMZ quicklink and carry one in my saddle bag. I've used the Shimano connecting pin one or twice with ok results but if it is not installed well it will fail and I've seen several fail. You have to be very careful with them. As others have said the push out/in method is an emergency temporary measure of last resort when you fail in the middle of nowhere without a quicklink and need to try and make it home and then trash the chain afterwords.

Marcus_Ti

OP...you mentioned a wheel change and the dreaded spacer....is there a chance your der stops not set correctly for the new spacing...and your chain overshifted into the gap of the dropout?



Don't the newer Shimano chains ship with a quick link link? Or am I remembering wrong?

FBinNY 

I don't believe that Shimano has moved to a connector, as have Sram, KMC, and Wippermann. Last I looked, Shimano and Campy stayed with a pin type system.

But that misses my point, which was that whether you use a designated splicing/closing pin or connector, you CANNOT properly cut and splice or close a chain by pushing a pin back and forth like we did before Hyperglide.

Marcus_Ti

I remembered it being announced in the spring, wasn't sure if it hit QBP/retail yet

Shimano introduces Quick-link for 11-speed chains | Bicycle Business | BikeBiz

Very true on re-using pins though ofc.

FBinNY 

As I said, I'm not sure on that point and don't buy Shimano 10 or 11s chains anyway.

Regardless of what Shimano provides, you already had the option of using a connector from another company.

The point isn't what the options are, just what they aren't.

cave12man

A lot of good info here, thanks again. I may have missed it but can you use an SRAM or KMC with Shimano? I'd like to stick with the quicklink if possible.

rmfnla

Yes...

ltxi

...and yes.

cave12man

This was also most definitely part of the problem now that I think about it. Was super excited to test out the new wheels and it probably suffered because of it. Lesson learned, at least it happened out my front door rather than 40 miles in.

Thanks again all, I'll be sticking with KMC this time round I think. The proprietary stuff on Shimano irks me for some reason.

cave12man

Ok, then here's another question. Can you use the other quicklinks with Shimano chains? Again, apologies if this was obvious from previous posts.

banerjek

Any of them work. I'm highly partial to the Wipperman.

A bit spendy, but by far the easiest to use. Plus you can use one link for at least 4 chains so the TCO is actually quite cheap.

cave12man

Awesome thanks, I'll definitely be checking them out in the future. Actually just ordered a KMC X10 SL in gold for a little bling factor. Fingers crossed!

BikingGrad80

Yes all chains of the same speeds are the same width (other than Campy vs Shimano/Sram). I've used both SRAM and KMC quicklinks with Shimano chains.