Replacing chain - how do I 'id' the old one?

Beansontoast
Beansontoast Posts: 75
edited February 2012 in MTB workshop & tech
People,

I need to replace the chain on my Specialized Pitch Pro (09 model).

Can anyone advise :-

1) Is there a way of identifying the chain currently on there?

2) How do I work out 'other' chains which are compatible ?

This bike was 2nd hand, so I can't rely on the original spec to tell me what the chain was.
Also, but until the chain wore, it was spot on with changes + response so I want to try and stick to the same combo.

I'm running X9 \ SLX.


Help appreciated.

Comments

  • benpinnick
    benpinnick Posts: 4,148
    Exact model will be had to identify, but if its got a power/breaker link, and KMC written on it, its KMC, an S thats on its side and looks more like an 8, is SRAM, and anything else (without a power link) is probably shimano.

    Any 9 speed chain will work, the more you spend the better its likely to be. KMC are highly rated, I personally like cheap SRAM ones as they shift well and don't break like the expensive ones do.
    A Flock of Birds
    + some other bikes.
  • nicklouse
    nicklouse Posts: 50,675
    they normally say on the side plates.

    keep the speeds the same and resize the new one.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Beansontoast
    Beansontoast Posts: 75
    Spot on - KMC 9 was the go ......

    thanks for the help.
  • Anonymous
    Anonymous Posts: 79,667
    Whatever it was, just get KMC anyway for the relevant speed. Sorted.

    Make sure you size the new chain accounting for stretch of the old if you're comparing the new against old.
  • 386ka
    386ka Posts: 479
    As I am aware, the chain doesn't actually stretch or grow, but wears. So, the length will be the same.
    A much loved, Giant Trance X3 2010
  • nicklouse
    nicklouse Posts: 50,675
    386ka wrote:
    As I am aware, the chain doesn't actually stretch or grow, but wears. So, the length will be the same.
    Nope it gets longer as it wears.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • 386ka
    386ka Posts: 479
    Really?
    Chain "Stretch"

    Cyclists often speak of chain "stretch", as if the side plates of an old chain were pulled out of shape by the repeated stresses of pedaling. This is not actually how chains elongate. The major cause of chain "stretch" is wearing away of the metal where the rivet rotates inside of the bushing (or the "bushing" part of the inside plate) as the chain links flex and straighten as the chain goes onto and off of the sprockets. If you take apart an old, worn-out chain, you can easily see the little notches worn into the sides of the rivets by the inside edges of the bushings. With bushingless chains, the inside edge of the side plate hole that rubs against the rivet has a smooth radius instead of a sharp corner. This probably contributes to the greater durability of bushingless chains.

    This is a quote from your sheldonbrown link...
    A much loved, Giant Trance X3 2010
  • oodboo
    oodboo Posts: 2,171
    386ka wrote:
    As I am aware, the chain doesn't actually stretch or grow, but wears. So, the length will be the same.
    I take it you've never used a chain wear indicator or the old fashioned ruler method?
    I love horses, best of all the animals. I love horses, they're my friends.

    Strava
  • oodboo
    oodboo Posts: 2,171
    You may get away with replacing just the chain but you might also find the cassette and chainrings are worn as well and need replacing.
    I love horses, best of all the animals. I love horses, they're my friends.

    Strava
  • njee20
    njee20 Posts: 9,613
    If we're being pedantic the chain lengthens but doesn't actually stretch. However 'stretched' it gets you can still use it to size a new one (assuming it was right), so it's a fairly moot point.
  • 386ka
    386ka Posts: 479
    oodboo wrote:
    386ka wrote:
    As I am aware, the chain doesn't actually stretch or grow, but wears. So, the length will be the same.
    I take it you've never used a chain wear indicator or the old fashioned ruler method?
    I have, but thought that it was only due to chain wear. The ruler method is another thing though. :D
    A much loved, Giant Trance X3 2010
  • njee20
    njee20 Posts: 9,613
    If the chain is under tension it will appear longer, but as above there's no plastic deformation of the plates as implied by the word so if you lay the chain on a bench (for example) you'll be able to get it to the same length as when new.
  • Anonymous
    Anonymous Posts: 79,667
    By 'stretch' I know I technically mean wear. I thought the pedants would be out when I posted but I couldn't be bothered to edit :D

    However, lay the chain out flat on the floor, and the new one beside it. The 'worn' one is longer for the same number of links. Handy way of sizing the new chain is by working out how much longer and cutting the new to size accounting for that, or just cut to the same number of links as the old. Either way the new will be shorter once cut to the correct number of links.

    Cassette replacement - only if the chain is quite worn else it probably has life in it yet. You'll soon find out as when you ride with a new chain it will skip on the cassette if it needs replacing.

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