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Short cage rear mech...removing chain link

Discussion in 'Bicycle Mechanics and Repairs' started by stevenb, 1 Sep 2007.

  1. stevenb

    stevenb New Member

    Location:
    South Beds.
    All,

    If I go for a short cage rear mech how many links will I need to remove from my chain?
    I run a 9 speed system with deore front, XT rear mechs and an SRAM PC951 powerlink chain.
    My XT mech looks as if it's on it's last legs.

    Cheers in advance.
     
  2. Yorkshireman

    Yorkshireman New Member

    Chain length is mainly determined by the sizes of the largest front gear and the largest rear gear, I use the Sheldon Brown formula = chain round both large gears (but not through the rear mech) + one link extra. The rear mech size is chosen depending on the size overall of gear ratio (it has to take the slack up when smaller gear combinations are used). I would think that if you haven't changed the gears you should keep the same size rear mech.
     
  3. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    a short cage XT mech is actually a medium cage so really it ain't that much difference tbh

    fit the new mech and as you are using a sram chain, you can join it up. put it in the smallest ring at the front and the middle of the block at the back. you can see if you need to remove a link or not.

    You shouldn't really use the smallest front ring and the smallest cog at the back together so its pretty irrelevant what the chain looks like in these gears.
     
  4. Yorkshireman

    Yorkshireman New Member

    Full instructions here (including why the chain length is important)
    http://sheldonbrown.com/derailer-adjustment.html#chain
    Note:- (copied from Sheldon Brown) "If the chain is too short, it will be at risk for jamming and possibly ruining the rear derailer if you accidentally shift into the large-large combination. Never run with a chain that is too short, except in an emergency."
     
  5. piedwagtail91

    piedwagtail91 Über Member

    i use the campag method of small,small and make sure the chain doesn't touch under the jockey wheel.
    i've an xt short cage and don't remember taking out any links.
     
  6. stevenb

    stevenb New Member

    Location:
    South Beds.
    Cheers for the info guys.
    I never use small small or large large combo's so no danger of that happening.
    :ohmy: