I have a Viking Torino 21 speed road bike. The bike has Shimano Sora derailleurs.

The chain is in need of replacing but I don't know what chain to buy. Here is a photo I have taken of the current chain, can anyone advise please?

KMC chain

  • 1
    Maybe go to your local bike store and get any old 7-/8-speed chain? I haven't bought one for a while but I remember the KMC chains were okay.
    – arne
    Sep 12, 2013 at 10:46
  • 1
    A 21 speed bike would have 7 rear sprockets, so you need a "7 speed" chain. Sep 12, 2013 at 10:49
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    That chain is a KMC Z chain which come in a few different sizes. As @DWGKNZ says, any 6/7/8 speed chain replacement will work. Here: (parktool.com/blog/repair-help/chain-length-sizing) is an article on how long to leave your chain.
    – WTHarper
    Sep 12, 2013 at 12:55
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    Note that, to install the new chain, you must first "cut" it to length, for which purpose you need a "chain tool". Thankfully, though, most chains (other than Shimano) now come with some sort of "quick link" for joining, so you don't need to be real proficient at using the tool. You should make sure that (after splitting) the new matches the old in number of links, not total length (since the old chain will have stretched by at least one link, maybe 2-3). Sep 12, 2013 at 14:49
  • Fyi, if your drivetrain is very old, you will most likely have to replace the rear cassette as well. Chains stretch over time and as the teeth on the rear cassette wear, the two become "compatible". If you put on a new chain without replacing the chain, the new chain mayskip teeth when it is under tension (like pedaling uphill).
    – user8139
    Sep 15, 2013 at 9:39

1 Answer 1


I can't help you identify the chain you currently have but the replacement would be any hyperglide compatible 7 speed chain. An example is a Shimano CN-HG50 6/7/8 speed chain.

  • Of course, the difficulty with Shimano is that it comes with those replacement pins rather than a quick link, so it requires some skill to install. Sep 15, 2013 at 13:06

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