So I broke my Shimano chain whilst out at the weekend. Didn’t have any spare links with me and was heading back to the car anyway, so refitted the pin that had come out with the chain tool to get me home.

Is there any way to find which link it was? Is it most likely to be the connector pin? Options seem to be to either replace the link with the connector pin (with KMC missing link), or run it till it breaks again – although impailing my testicles on the stem isn’t that appealing an option.

Get a cheap chain checker, see if its stretched and needs replacing first off. Then look for twisted sections of chain along three or for links either side of where it snapped. If there is s twist its normally because the chain has previously been thrown off and wrapped round the cranks or excessive pressure applied to cranks while shifting.
Normally chains for me only break when worn or damaged by my clumsiness although did have one go two weekends ago on outer plate/pin failure. I always carry a mix of SRAM/Shimano Pin and KMC type links as I once had a Shimano 9 speed chain that KMC link was too thin for!!

Chain hasn’t done 15 miles yet, so no previous damage or wear. Must have had one too many Weetabix that morning. 🙂 10 speed too, so that prob didn’t help.

The link that broke was slightly bent, but straightend out after I put the pin back in. Now they all look exactly the same. Nothing else twisting. Thinking it must be the link with the connector pin, as I don’t think another pin would have went back in (feel free to correct me if I’m wrong about that).

May just have to wait till it goes again to find out which one it was, cos it’ll no doubt be the same link as it’s weakened now. Good idea keeping a selection in your pack. I’ll be doing just that myself now.

I’d be surprised if you can’t spot a tiny difference if you really look at the heads of the pins and the holes in the side plates. When the chain is riveted together the ends of the pins are spread out slightly over the edges in the holes in the plates, once it’s been apart and had the same pin pressed back in the holes in the plates will be a tiny bit stretched and the edges on the spread out end of the pin slightly taken off so you’ll probably be able to spot one pin where you can see the extra deformation in the plate around the holes. You might be able to see the edges of the holes in the plates on that one but not on the others.
No guarantees, but worth a very careful look.

Ah right a new chain snapped. Did you shorten it or was it already fitted to a new bike? If it was new bike I would suggest its faulty manufactiring of chain, try get a replacement from the sellers. I would be tempted to ditch the chain a stick a new one on anyway if one links already gone, like you say testicles on top tube smarts.

Meh – I’ve had chains last for a lot of miles after being put back together carefully. There was a time before I knew connector pins existed and I just used to choose a link at random to use to split and rejoin the chain. If you cant spot the one you rejoined, just forget about it and ride the thing.

Had a good look with the torch shining on it and the connector pin is the only one that looks any different. Was a friend that fitted it, as I was fitting brake rotors at the time. He might have taken a few links out, but not sure. Will have another close look and see if I can find any deformation.

Bit disappointed it went so easily. Options are limited for a replacement cos it’s dynasys. I think a KMC chain would be ok, but will have to look into it further.

I’m pretty sure any 10 SPD chain that states “Shimano compatible ” will do for a dyna sys setup.

dantsw13 – Member
I’m pretty sure any 10 SPD chain that states “Shimano compatible ” will do for a dyna sys setup.

I’m running a Shimano 10 speed compatible SRAM chain and have been for a while. It’s deffo not a Dyna Sys as they irritated me with their link pins.

I run a SLX chain, but don’t use connector pins. I use YBN quick links, which seem to be the cheapest ones, and have been great for over a year.