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I am replacing the chain on my road bike soon. How do I know how many links to get? Does it have to exactly 114 or 116. Or is it not a big deal?

I ordered a 116 link chain. Will I need to shorten it?

Thank you.

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If your old chain was 114 links (assuming it was the right size to begin with) then it's a good idea to take a couple of links out of it. It'll still work with two extra links but shifting may not be optimal and the chain will fall off more easily. Keep in mind that one chain link is composed of an inner and outer link, so a link is actually two pieces with a hinge in the center. This means that to remove two links, you'll actually remove four pieces of chain with three hinge points.

If the old chain was 116 links and you're trying to replace it with a 114 link chain, you'll run into problems. A chain that is too short can jam when shifting and puts puts too much strain on your rear derailleur.

To determine the correct length, wrap your chain around largest chain ring in the front and the largest rear sprocket, without running it through the derailleurs. Make sure that the chain is long enough for one full link (again, inner and outer) to overlap and you'll probably be spot on.

You can read more about it here: http://sheldonbrown.com/derailer-adjustment.html#chain

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    Last two paragraphs "rule". Actually, most chains already come with extra-length, so shortening is almost always necessary. The procedure to measure the chain (instead of some other calculation), is what settles the correct length, in the end.
    – heltonbiker
    Jul 3, 2012 at 16:26
  • I would summarize this as "Count the number of links of your to-be-replaced chain".
    – sancho.s ReinstateMonicaCellio
    Apr 19, 2022 at 8:08
  • @sancho.sReinstateMonicaCellio I wouldn't summarize it that way, nor would I advise that. Using the existing chain as a guide assumes that the existing chain was the right length, which I wouldn't. Rather, I'd measure it using Sheldon's method, which I describe in the answer. That gives you the correct length, regardless of the previous chain. As a couple of bonuses: you're less likely to make a mistake and it's faster and easier.
    – jimchristie ♦
    Apr 19, 2022 at 12:35
  • Sheldon's method is great for setting the chain length once you have the chain in your hands, which assumes the chain length is enough for one's needs. The OP asks how to tell which chain length to get (114 or 116 links, and I would add 118 as some chains have that length). I don't see how you would come to the right number using Sheldon's method. If you could clarify that, it would be great. I counted 53 full links in my old 3x7 Shimano STX, so I assume that would be 106 in the lingo of products description, and even 114 would be enough then.
    – sancho.s ReinstateMonicaCellio
    Apr 19, 2022 at 12:44
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    @sancho.sReinstateMonicaCellio I think I see where your'e coming from now. The question could probably be clearer. You seem to be focusing on the title, which is phrased as what to get. I focused on the body, which indicates that the OP has already purchased a chain and wants to know how to tell if it's the correct length. Yes, as Daniel R Hicks points out, new chains are typically much longer than needed. I usually just buy the longest one I can find and shorten it using Sheldon's method. I've never once counted links and don't advise it, for the reasons I've stated.
    – jimchristie ♦
    Apr 19, 2022 at 13:42
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A standard replacement chain is always several inches longer than needed for a standard non-recumbent, non-tandem bike. What I generally do is hang both from a wire and match up the links (the old chain will be "stretched", so you can't simply match by length). Then I "break" the new chain at the location (number of links) that matches the old.

Skilled mechanics can simply stretch the chain around the big rings front and rear, put their finger on the link that meets the other end, and break it there, but I'd rather be sure that my new chain matches the old exactly (if the old performed well).

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  • Isn't the "stretch" just the wearing of the joint between links? So each link should still be the same length, yeah? Which means hanging it from a wire should work just fine.
    – Sponge Bob
    Jul 2, 2012 at 18:36
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    @KeeganMcCarthy, the stretch is indeed just the wearing of the joint, and though each individual link remains the same length, a chain of them is longer. In other words, a stretched chain with 100 links will be longer than a new chain with 100 links.
    – amcnabb
    Jul 2, 2012 at 21:07
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    Specifically, if you the 1% on the gauge 'just' drops, and you started with 100 links, your old chain will be one link longer than your new chain. (In practice, most of the chains I fit onto backs run a few more than 100 links...but I find this visualization good when I start drawing pictures of what's actually happening when the chain "stretches").
    – Ken Hiatt
    Jul 3, 2012 at 0:11
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    Yeah, when I replace a chain it's usually at around 0.8% worn, so the old chain (which is a hair over 50 inches/100 links) is about one half inch longer than the new chain should be. And a link is one half inch, so the old chain will appear to be one link longer than the new one should be. But it's the same number of links.
    – Daniel R Hicks
    Jul 3, 2012 at 0:26
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I am writing a summary answer. It does not contain new info, but I would have benefited from having it as such, so I expect it might be useful for others as well.

How do I know how many links to get?
To be completely sure, you would count the number of links in your current chain, assuming it is ok. Nevertheless, that is almost never needed. Chains sold are usually longer than whatever is needed. I have to change now a chain with 106 links, and the shortest chain sold has typically 114 links.

Does it have to exactly 114 or 116. Or is it not a big deal?
As per answer above, it is not a big deal.

Will I need to shorten it?
Most likely, yes. How? See the cited link from Sheldon Brown.

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    Not sure why this is necessary? SEs vote system allows the best-ranked answers to move upward to the top and be read earlier. You might want to check the "sorted by" option, which is located above the first answer.
    – Criggie ♦
    Apr 19, 2022 at 21:08
  • @Criggie - On one hand, I found the answers and exchanges in comments useful. I have actually upvoted some of the above. OTOH, as stated in the answer, I would have benefited from my concise answer were it available, it contains the conclusion of my reading and checking. Thus I took the time to post it, with the intention of others perhaps seeing it the same way. Of course it would have been easier for me not to do that. If you and/or others do not see it contributes, it is fine to downvote it, I'm OK with that. (I am a regular at SE sites).
    – sancho.s ReinstateMonicaCellio
    Apr 21, 2022 at 12:52
  • yeah its a conscious design decision by SE to differentiate things from a common chatty web-forum. If you've ever had a search engine suggest bikeforums.net or bentrideronline as a result, it can be highly frustrating to wade through posts. With the Q&A, the "best" answer gets upvoted. So you'd presume that a summary post would do well, but they tend to be viewed as "Rep farming" and busier SE sites just delete them out of hand.
    – Criggie ♦
    Apr 22, 2022 at 2:42

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