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front deraillur question

Discussion in 'The Shop' started by 1453, Feb 10, 2008.

  1. 1453

    1453 Monkey

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    So I got a frame that is the same as this:



    I got it cheap and new, and intend to use it as a trail bike(not hardcore stuff) and my girlfriend just got me a DHX 5.0 for it since I'm a lard ass(that can bench press a bit of weight).

    What derailleur do I need for the front? I have a blackspire bash guard and just want to run the middle and small rings. The diameter of the "seat tube" is 31.8mm. I'm however a little confused with the top-swing and bottom swing stuff.

    I have worked on my own bikes forever now but haven't used a front derailleur in 6-7 years.

    Thanks,

    1453
     

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  2. Quo Fan

    Quo Fan don't make me kick your ass

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    Here. I'm just not sure where "here" is.
    That frame would take a 31.8 diameter, top-swing front derailleur.
     
  3. HAB

    HAB Chelsea from Seattle

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    Right. Also known as a 31.8mm low clamp derailleur by some. Also, it needs to be a bottom pull.
     
  4. 1453

    1453 Monkey

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    thanks, folks.

    Does top-swing=bottom pull?
     
  5. HAB

    HAB Chelsea from Seattle

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    No. Top swing refers to the relation of the parallelogram mechanism and the clamp. Top swing derailleurs have a low clamp. Bottom swing ones have a higher one. Bottom pull means that the cable comes at the derailleur from below.
     
  6. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Any new standard top swing derailleur will work by Shimano. They use a clamping shim to work for all tubes and will have the ability to pull either direction. I know this is certain for Deore and XT. Pretty sure about LX, but XTR may be specific. Hope that makes a little sense.
     
  7. 1453

    1453 Monkey

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    thanks a lot guys.