I'm trying to replace my rear derailleur on my cheap MTB. Chain is a KMC with a Z and NARROW on it. There's no master link so I bought a tool but i can't get it to push a pin out. Are the pins one direction? Thanks, Justin

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    Sometimes you need to twist REALLY HARD. Best to experiment on a scrap piece of chain until you get the hang of it. And count your turns, once you know (from experimenting on a similar width chain) how many turns you need to get the pin almost out. – Daniel R Hicks Mar 21 '19 at 20:06
  • @DanielRHicks: Why would you only want to get the pin almost out? I hope you don’t suggest re-using pins. – Michael Mar 22 '19 at 8:57
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    @Michael - Depends on the chain. For a 5/7 speed you can generally reuse the pin, if you're careful. For narrower chains the manufacturers don't recommend it (though I would certainly try if I didn't have a replacement pin/link). – Daniel R Hicks Mar 22 '19 at 11:42

Pins can be forced out from both sides.

Quite a lot of force needs to be put on a pin to force it out, especially at first to move the pin out of its interference fit in the outer chain plates.

Make sure the chain is positioned in the chain tool properly, and the driver is hitting the chain pin straight-on. If you have a small chaintool, such as one from a portable tool kit, you won't have much leverage. You can hold the tool with a large adjustable wrench and turn the handle with pliers.

Don't be afraid to really force it. IF you are replacing the chain you wont break anything you care about.

If you want to re-use the chain you need to careful if you have unsuccessfully tried forcing more than one pin out. You may have moved a pin slightly and weakened it. If you suspect you have done this a new chain may be a safe option.

I linked a Park Tool video on replacing a chain below that includes how to break a chain.

  • Why do you say he's "trashing" the chain? It can be reconnected, if the process is done properly. – Daniel R Hicks Mar 21 '19 at 22:23
  • @DanielRHicks I assumed OP is replacing chain, but I guess they might not be – Argenti Apparatus Mar 21 '19 at 22:28
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    You often need to break the chain to replace a derailer. Some derailers can be disassembled to avoid this, some not. – Daniel R Hicks Mar 21 '19 at 22:35

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