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My previous chain snapped weeks ago and only got a new one sorted.

I've cut the chain to the right size, fed it through the derailleurs and onto the bike correctly.

The last step was to use the reinforced Shimano pin to connect the new chain together. Unfortunately the reinforced pin snapped as it was being put into its slot.

My wife was doing it so I'm not 100% sure what happened but she said it snapped very easily and unexpectedly. My only guess is that the chain tool wasn't going straight?

Anyway, the actual link that you'd want to stay in and connected, wasn't far enough in yet so it fell out, the 'snapping' bit is now stuck pertruding out of the chain.

I've never replaced a chain like this before so I'm slightly weary of doing damage. It'll be tricky, but should I be able to use the already snapped pin to connect the chain and hopefully it'll help push out the snappable portion?

Should I attempt to get another reinforced pin instead of attempting the above and start again?

I could attempt to pull out the 'snappable' portion with pliers but again slightly worried about causing damage!

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    Your guess about what happened is likely correct. Always make sure that the chain tool's head presses dead straight against the chain pin center, and that it does not touch chain side plates. You can use pliers to align the broken part before you start trying to press it out. – Grigory Rechistov Jan 8 at 8:37
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    There's really no reason to buy a chain that requires a pin to connect it. Just buy one that uses a quick link/master link. (KMC...) It'll probably be cheaper than a Shimano chain too. (And that Shimano chain was likely made by KMC anyway...) – Andrew Henle Jan 8 at 12:06
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    @AndrewHenle : And nowadays even Shimano sells (11 speed) chains that connect with quick links. – Carel Jan 8 at 17:05
  • amazon.co.uk/Oumers-Mountain-Bicycle-Splitter-Breaker/dp/… - this is the tool I used, is this potentially a bit too rubbish? – shicky Jan 8 at 22:07
  • Just take it to a bike shop. – Daniel R Hicks yesterday
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I think you can drive the detached 'leader' part of the pin out, then drive in a second connector link as normal.

The part of the connector pin that stays in the chain has a slightly greater diameter than the regular pins so that it has an interference fit in the link plates. This is why if you want to re-break the chain you have to do it at a different link. The first pin would widen the hole in the link plate then the second pin would not have the proper interference fit.

The leader part that gets snapped off is of slightly narrower diameter and just serves to line the link plates and roller up properly. That means you can drive the snapped off one through without damaging the link plates, then drive in a replacement connector link.

  • do you have a video you'd recommend of the process? I copied the length of my last broken chain, however, it seems like this may have been too short based on the amount of tension on the chain? – shicky Jan 8 at 22:27
  • should you also apply the new connector pin from the 'frame' side or toward the bike? A park tool video suggested from the frame side but frankly, this seems impossible given the space – shicky Jan 8 at 22:41
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    @shicky If the chain can be put onto the large sprocket/large chainring then it's OK. If you think you've made the chain short be careful testing this as a short chain can do damage. Do this with the bike in a stand turning pedals by hand, NOT while riding. I size my chains from the old one, but this is the best way to do it if you don't have the old chain youtube.com/watch?v=LC8_ndnXJUY – Argenti Apparatus Jan 8 at 22:43
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    @shicky I don't think it matters much, I use KMC quick links myself. If you want to do it from the frame side take the wheel out. – Argenti Apparatus Jan 8 at 22:46
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You can often use the chain tool to drive the half-way inserted pin back out from the chain. I do not think it is advisable to attempt pressing it in again. It is certainly possible, I did re-pressed regular roller pins a couple of times when I or someone else accidentally pressed them out too far so that they fell off. It is not the most enjoyable experience, especially as the roadside repair.

You can get another reinforced pin and try again. Alternatively, you could get a so-called master link which replaces one of the half-links on the chain (presumably one at the end of your chain with the broken pin sticking out of it). The master link allows to close the chain using no tools at all, and often to open the chain using special pliers (or just bare hands, with enough swearing).

master link

Several companies manufacture such links for chains of different widths (for cassettes from 8 to 12 speeds). They are generally compatible with chains of all vendors, e.g. you can use a KMC master link on a Shimano or SRAM chain with no issues.

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    The downside of master links is that (with some exceptions) you end up having to carry two tools - a chain breaker and a master-link tool. There are tyre levers incorporating the master-link tool but they're not as good as the proper pliers – Chris H Jan 8 at 13:48
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    @ChrisH : It is actually possible to open quick links without a tool in an emergency. There are videos on the net showing how it's done. In a workshop you'd still use the proper tool, of course. – Carel Jan 8 at 17:09
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    @Carel I've never found a method that works for me. I've tested a few on old chains at home before giving up – Chris H Jan 8 at 18:47
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    despite my chain not being a masterlink chain, can I essentially add masterlinks to it? I didn't realise getting the pin to connect the chain would be such a pain in the nuts, it's quite awkward to get in place or perhaps it just shows how rubbish I am at it – shicky Jan 8 at 21:26
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    FWIW, can confirm that 8-speed SRAM links world fine on 8-speed Shimano chains too 👍 – Lamar Latrell Jan 8 at 23:29
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I would use your existing 'snapped' connector pin and drive it in with the chain tool to force out the piece that is stuck (as you suggested in post).

I would then drive out the connector pin with the chain tool (as if I were breaking the chain).

And finally I would start over with a new connector pin. It's definitely worth carrying a few shimano pins and quick links in your saddle bag. They are cheap, weigh virtually nothing and can save you a long walk home.

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    You can't drive a connector pin through the same link more than once. The connector pin has a slightly greater diameter than the regular pins so that it has an interference fit in the link. The first pin would widen the hole in the link then the second pin would not have the proper interference fit. – Argenti Apparatus Jan 8 at 15:06
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    Interesting. Makes sense, but I didn't know that. In that case, could get a spare pin by breaking a spare link and using that to drive out the broken section before trying again with a fresh connector pin? This way the wider section of the connector pin would never have been through hole. – Andy P Jan 8 at 15:18

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