How can I shorten a new chain to a specific length if not all links are either master links or have a removable pin?

Question

I am confused about whether chains come in two kinds (1. push-the-pin, 2. master link), or just one kind. Specifically, I'm confused about the following.

1. Can any chain be broken at an arbitrary pin? (Or do I have to look closely at each pin to identify those pins that can be pushed out with a chain breaking tool?)
2. After it is broken, can any chain be connected with a master link? (Or do I have to order a chain identified by the vendor as "master link missing" to know that it is of the kind that can be reconnected by a master link?)
3. As Vorac points out, a new chain will arrive with a protruding pin (see image below). This pin can be safely pushed back in (how? by any ordinary set of pliers?) after breaking the new chain at the correct length (which obviously has to be matched with inner, not outer, plates); is that right? (yes, yes, it's obvious that I need to match the number, not the length of the chain since the old one will surely be longer).

4. If, however, I lose (for whatever reason) the protruding pin that appears in the image above, I cannot use any pin that I have previously broken off from the chain. I must order a new pin. (I might get away with not heeding this advice, but the chain will risk breaking at the worst time; just when I'm applying a lot of torque.) The pin that I order will look like the one Criggie illustrates. Did I get that right?

Answer 1

1. Speaking in terms of a new chain out of the package, yes, regardless of what chain it is you can use any pin to do your sizing. If it's a chain that uses a one-use pin such as most Shimano chains until recently, or if it's a half-link chain, or if you're using a half-link, when doing so you'll leave it with an inner link on one end and an outer link on the other. In other instances such as a two-piece master link (the most common type for all derailleur bikes nowawadays) or other master link, you'll leave it with an inner link on each end. If you were to ask this question in terms of where can you break the chain when it's installed on the bike, the answer is you probably could drive out any link, but you want to avoid doing it to one that's part of a master link because those are special and who knows how much force it would take. You should also never drive out a factory connecting link or a formerly installed one-time pin when you're planning on putting a new one-time pin through the same outer link. In other words, the outer links on chains that use one-time pins should only ever have a new pin pushed in once, and so when you go push a pin out of an outer link you're planning on putting a new pin through, you should select a link that's one of the "normal" links on the chain, not any kind of special pin (which all look cosmetically a little different on chains this applies to).

2. This question gets bogged down because it's asking for a survey of all bicycle chains in history. You could probably find some specimens that have some quirk that makes them ineligible to work with any extant master link. Among recent chains, basically all of them have some kind of master link available that will work fine, but in some cases that's only true by virtue of the availability of a third-party link. For example, until recently Shimano didn't produce or condone 2-piece links for their chains, but KMC has been making Shimano-compatible ones using the SRAM/Sachs design for a long time.

3. Chains that come this way are intended for plan A to be trim the other end for sizing and then connect it using the partially pressed pin they give you. Chains like this may or may not also be able to have fully installed pins pressed out and back in safely.

4. Many chains that come new with a partially pressed pin are older styles and are able to have pins driven in and out if needed, but not all. Generally speaking all true 5/6 are like that, but once you get to 7-speed or more, it goes by manufacturer. For example, Shimano says no, only use a one-time connecting pin, while KMC I believe condones driving pins in and out of all their 7 and 8-speed chains. So in that situation, yes you may need either an appropriate master link or connecting pin. Two-piece master links are generaly regarded as more practical and popular. There's nothing wrong with pins if the chain is comaptible with them, although some are put off by the one-shot nature of the system. It's critical to understand that connecting pins are brand-specific, and only a couple of chain companies (Shimano and Campy) have employed them. You can't safely put a Shimano 10 pin on a KMC or Campy 10 chain, etc. Two-piece master links don't have perfect interchangeability between brands, but in a lot of cases they come close (AFAIK all the 11-speed ones work on all 11-speed chains, for example, and on 9 and 10 it's basically Campy that comes up as the outlier and Shimano, KMC, and SRAM can all use the same 2-piece links).

Answer 2

I think you're blending quick-links (aka master links, you're calling them a "magic link") with replacement pins. They do the same job, in different ways.

Any pin can be pushed fully out of a chain. The tool required is a "chain tool" and generally has a threaded design.

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Modern chains have become too narrow to just push a pin mostly out and then back in with a chain tool. While 5/6 speed chain was generally fine to half-push a pin and then reinstall it. From about 10 speed upward, this is strongly discouraged. The 7/8/9 speed chains are in a grey crossover area.

Old-school way of pushing a pin almost-out. (Very worn)

Instead we have a choice of a one-time pin that is inserted once, then snapped flush. If you break the chain again, you want to choose any other pin to push out. This is ONE PIN.

Or your second choice is the quick link, which replaces a pair of OUTER PLATES in your chain. They can generally be open/closed several times.

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So any bike chain can be used with a replacement pin or quick link in the same "speeds" meaning the appropriate width. When using a quick link, you have to remove one set of outer plates and that's where the quick link goes, leaving the same total number of links (or half links if that's how you count.)

Answer 3

I don't know any chains that can't be shortened by removing pins. As opposed to old chains, where link removal required little force (they didn't have "punched" pins with mushroom heads) and pin removal didn't damage the chain so you could push it only partway out and reuse the same pin to connect the chain later, new chains with "punched" mushroom head pins suffer damage when a pin is pushed out, and you can't reconnect the chain by using the same pin. There are two solutions that allow reconnecting a modern chain: (1) special reinforced connecting pins that are single use only and are designed to fit into the holes damaged by pushing a factory pin out, (2) so-called "quick" links (which should be called slow links instead because it takes forever to disconnect such a link without pliers if the chain is dirty).

Choose your poison. I choose reinforced connecting pins and avoid "quick" links because they can't reasonably be disconnected in a dirty chain without carrying pliers.

And to the second question: most chain tools work with any width of chain. You don't usually need a different chain tool for different chain width. There can be some exceptions, so for example if a chain tool says it can't be used for 12-speed chains, that might be true.

Answer 4

What there is a "quick link" on the chain, does not mean you cannot use the chain breaker to split it at any other point, and this is how you shorten it. Any pin is removable if you do not need to put it back.

The quick link from the discarded segment can be then attached to that split point. There are inner and outer links, and inner always pairs with outer. Hence to be able to close the chain when on the bicycle, you can only remove even number of links (2, 4, 6 ...). The quick link is an outer link.

In my case (KMC X9) the quick link was included with the chain, no need to order separately.

Answer 5

I'm certainly misunderstanding something here as the authors of the 2 already published answers are bicycle gods. But I will speak my mind nevertheless, the downvote button is to the left.

All the bicycle chains I've ever purchased end with this on one end:

Not mushroom tip though - I'm extremely stingy and buy the cheapest that works. So cutting the chain from the other side has always worked, including for a 10-speed.

Perhaps this is unsafe, perhaps I misunderstood the question. I've had 1 chain fail out of tens and only after repetitive mudbaths and then jumping onto the pedals.

Answer 6

There is yet one more part to the question that was not asked. I'll go ahead and answer it here.

Shimano Chains

You do not need to order an extra pin.

That's because if you order a chain

there will be one pin in the package.

Still, carrying around an extra pin might be good for safety. If you're on the road away from home and your chain snaps, you will be able to get home if you carry a chain tool and an extra pin.

Needless to say, you need to order a 9-chain pin for a 9-sprocket chain, and 11 for 11, but that's obvious.

KMC Chain

Likewise you do not need to order a master link.

(Which, by the way, KMC calls a "missinglink")

When you order a KMC chain, there will be one such link in the package—nicely and prominently displayed to remove any doubt.

SRAM Chain

As with KMC, SRAM includes a master link, but SRAM call their master link a "PowerLink".

One PowerLink is included with a SRAM chain.