What Is a Bike Chain Master Link and What Does It Do?

The 11 month old chain was used for 2,992 miles.
Daniel Oines/Flickr/CC BY 2.0

The master link is a single removable link segment of a bicycle chain.You'll hear people also refer to these as quick links. Also, SRAM's version of the master link is called a Power Link. It is sold separately as well as typically included when you buy a SRAM chain.

Master Link Backstory

Sometimes you simply need to take off your bike chain. For instance, if you want to take it completely off your bike in order to do a thorough cleaning (and not just a quick and easy chain cleaning).

But the problem is that with the way bikes (and bike chains) are designed, you have to break the chain to get it off. Destroy the village to save it, that sort of thing. Using a special tool, you crush one of the links, and then the chain can be removed. This whole concept sounds painful.

That's what a master link is such a great thing. It's an itty-bitty part, but might be the best piece on the whole bike. The master link is a single removable link segment of the chain. It is not permanently fused like all the other links, which allows you to remove your chain at will, taking it off and putting it back on when needed. A master link can either be installed with a new chain or else used as a replacement piece when putting your current chain back on after you've had to break a link to remove it as described above.

A master link looks basically like your normal segment of chain link, except that one side has a flat washer that mimics the normal side piece of the link and next to that, to a removable link-shaped clip that slides on and off, usually with the help of a screwdriver, when mounting or removing the master link.

Master links are cheap, too, usually only a few bucks. You can find them online or at your local bike shop.

Emergency On-the-Road Repairs

The other big reason to be a fan of a master link is their function in saving your bacon if you're out riding and your chain breaks. You know the phrase, the "weakest link"?

 It's true, and plenty of cyclists have been out riding and been stuck miles from home when they're really hammering, mashing down on the pedals and suddenly their chain breaks when a link fails. If a rider can produce a master link from her bike bag, she's got a way to repair her chain and get back home.  Without it, it's time for a really long walk. Many experienced cyclists carry them as a matter-of-habit and a cheap insurance policy against mechanical failure.