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I am considering getting a new front derailleur. Since the derailleur is riveted together so far as I can tell, it looks I will need to break the chain. The chain doesn't have a master link, so I'll need to use a special tool to push one of the pins through. After I do this, will I be able to secure the chain back together after I install the new derailleur?

  • I have yet to see even the cheapest derailleur that didn't have a screw to allow it to be removed w/o disasembling the chain. It is often not very obvious that the screw exists to allow you to do this. Can you post a picture of the derailleur? – Fred the Magic Wonder Dog Sep 24 at 19:24
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Fifteen years ago the answer was a simple "Yes". Today's 10, 11, and 12 speed chains are not designed to be reassembled this way, and in fact, will reliably break or fail where you reuse the rivet. For these new narrow chains, simply use a replacement rivet on Shimano, or master link on SRAM or other.

For older bikes, or chains designed for 9 or fewer rear cogs, see below:

The same tool that you use to break the chain can be used to push the rivet back in. The trick is to make sure that you don't pop the rivet all the way out--it needs to stay in one of the sideplates. A lot of chain tools will stop automatically before they pop the rivet all the way out.

Alternatively, you can remove the rivet entirely, and the outer half-link, and replace that with a master link. You can get individual master links. These need to be sized to your chain (so if you have a 9-speed drivetrain, you'll have a 9-speed chain, and need a 9-speed master link).

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    By "9-speed" in this instance, are you referring to the number of chain rings on the rear cassette? Mine has 7 in rear, 3 in front (21-speed). Edit: and are all master links compatible with all chains assuming the speed is correct? – oscilatingcretin Sep 20 at 1:23
  • Yes, by 9-speed, I was referring to the number of sprockets in back. As far as I know, master links are compatible with all chains of a given width, although there may be outliers. The master-link packaging will probably indicate what it will work with. – Adam Rice Sep 20 at 2:56
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    Driving the pin back in is not recommended even as a stopgap by many manufacturers, at least on narrower chains (higher gear count). A master link is a better option for most, though for some Shimano chains you can get a special pin to replace the one you took out. – Chris H Sep 20 at 5:40
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    @ChrisH: Shimano expressly declares that you must not re-use a rivet that has been pushed out. A new one must always be used and the pins for each type of chains are different. Replacing the rivet with a master-link is definitely the best solution. – Carel Sep 20 at 6:43
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    I can say from experience that a SRAM master link had a very difficult fit to a shimano chain, while fitting perfectly in a SRAM PC chain (both chains for 8-gear rear train) – Ilia Gilmijarow Sep 20 at 16:09
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For reasons of basic longevity of your chain split tool, I recommend you use a grinder to grind the head off the pins, right the way down to the face of the link. This will make the pin far easier to press out and less likely to ruin your chain splitter by bending the drive pin. Pins are usually retained by peening - flattening the protruding end so that [parts of] it become[s] wider, like a mushroom head. While you can force this wider part of the pin back through the smaller hole in the link, if the peening has made it dome shaped you run the risk of your chain tool push pin going sideways and becomeing bent/useless. By grinding/filing the wider part of the head off the pin you make it a lot easier to remove because it's being pushed through a hole that is the same diameter as the pin is

After you split the chain, discard the link you hit with the grinder and replace it with a split link or other replacement link designed for the chain

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    I've not heard this recommendation. You can simply press a pin out with a chain tool. It isn't hard. Also, if we are talking a pin that's still in the chain ... what do I grind? The surface of the pin is more or less flush with the side plates. If you can provide a link with pictures or video, that would help. Or aam i missing something? – Weiwen Ng Sep 20 at 19:12
  • Grinding is risky at best as it's easy to nick up the side plate. A rotary tool with a small stone is more accurate but the risk remains. Compared with the possibility of a bent pin....you decide. Shimano chains rarely stay together if the same pin is pushed back into place (my experience). KMC does. Master links are the way to go, even with Shimano chains (not recommended by Shimano below 11 speed), never been a problem, including noise, over thousands of miles and many years with multiple brands. – Jeff Sep 21 at 15:17

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