How can I identify the make and model of a chain?

I need to take a chain off and clean it. (It's a new-to-me used bike, and I'm giving everything the once over.) The chain doesn't have a master link, so I'm going to have to break it and add a master link. To do this, I need to figure out what kind of chain it is so I can get the right master link.

(It might make sense to just get a new chain given relative prices, but I'd rather keep the chain I have because this is my knock-around bike and I don't want it to look new, I want it to look not worth stealing.)

Looking at the chain, it says KMC, NARROW, with a stylized Z. The bike is a 3x7 department store bike. The rear cogs say Shimano MF-TZ21.

Here's a picture.

chain close-up

  • 1
    You should check for chain stretch (see this question) and replace the chain if it has stretched too much, otherwise you might go over the handlebars like I did once. Don't worry, a new chain will get grimy from road dirt very quickly so that nobody will be able to tell that the chain is new.
    – rclocher3
    Commented Aug 18, 2016 at 16:17

2 Answers 2


Any brand link that is rated for a 7 speed chain will fit. Sram refers to there's as a Power Link, KMC calls it a Missing Link other are quick connect. What is important is that it not the type with the "U" clip that it together. That type is only for non derailleur bikes.


It looks like a variant of the KMC Z8, with a pin length of 7.1mm:

enter image description here

The KMC website suggests using a MissingLink 7/8R 7.1mm (although others should work as well, as mikes points out).

  • Looking at three variants of the chain (Z7, Z72, and Z8, here: kmcchain.us/chaintype/z-series-8-speed ), I see two marked for internal gear hubs and one not. The two have flatter pin ends, while the one has mushroom ends. Is that because the mushroom ends have clearance problems inside internal gear hubs but work fine with open gears?
    – compton
    Commented Aug 18, 2016 at 12:32

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