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Help - SRAM chainset removal

  • 01-09-2014 7:20pm
    #1
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭


    Hi

    I am trying to remove a SRAM chainset from a bb.
    I have used an 8mm Allen key to remove the nut from the centre of the crank arm.

    However the crank arm will not budge from the spindle at all.
    I have tried leverage and that won't budge it.

    There appears to be nothing else that I can unscrew.
    Any ideas? What could I be missing.


Comments

  • #2
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    I have attached a picture.


  • #3
    Borderfox
    Registered Users, Registered Users 2 Posts: 10,263 ✭✭✭✭Borderfox


    ROK ON wrote: »
    I have attached a picture.

    A crank extractor fits into the thread in the hole to pull the crank off


  • #4
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    Borderfox wrote: »
    A crank extractor fits into the thread in the hole to pull the crank off
    Ok
    That would be necessary then?

    I have checked sram YouTube videos and other videos concerning sram cranks and not one mentions a crank extractor. Strange.

    Will any crank extractor do - I can't find a sram one on wiggle/bike24/crc.


  • #5
    Al Wright
    Registered Users, Registered Users 2 Posts: 168 ✭✭Al Wright


    From the picture it appears that crank spindle is hollow, therefore a standard crank extractor will not work, (nothing for the extractor screw to lever against). It appears that the crank is a straight spline engagement, so it should just slip off. It has probably seized over time. Try tapping out using wood wedges between crank and bottom bracket bearing face. (the risk of using a heavy screw driver is that the bearing seal could be damaged. It the intention is to replace bearings then this isn't an issue)
    I'm not familiar with the Sram, but a similar looking arrangement uses the cover piece through which the 8mm Allen screw goes as an extractor. If there are fine threads on the inside of the crank between the outer edge and the spindle this might be the case. If the 8mm Allen screw has the bezel still fitted there is a chance that this is of that type.
    Search Google for 'Self Extracting Crank Bolt' for a description.


  • #6
    ashleey
    Registered Users, Registered Users 2 Posts: 2,005 ✭✭✭ashleey


    Something has gone wrong for you. The nut should stay with the crank arm and push the crank arm off the spindle. The nut is not removed from the arm. I would try to reassemble and check that you are turning the nut in the right direction? If not you are a bit stuck as the arm is still gripping the spindle with no method of loosening.


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  • #7
    vertigo1976
    Registered Users, Registered Users 2 Posts: 126 ✭✭vertigo1976


    On my Sram force GXP crank, you leave the larger outer allen nut in place and as you loosen the inner 8mm one it self extracts the crank. Hope that makes sense.


  • #8
    The tax man
    Registered Users, Registered Users 2 Posts: 4,559 ✭✭✭The tax man


    Thinking along the same lines as Al Wright. Self extracting type setup. Was there a threaded ring around the bolt that held the crank arm onto the BB spindle? When I first came across this setup I thought I had to remove the ring instead of leaving it in place.
    http://www.parktool.com/blog/repair-help/self-extracting-or-one-key-release-systems


  • #9
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    Thanks for the replies folks - I am attaching more pics.
    You will see that there is a thread inside the crank arm.

    This thread is not for the crank bolt - so I figure this is what I should thread the extractor tool to in order to unscrew the crank arm.

    Would any store in Dublin have one of these - I figure bee cycles does as he bilt the bike - but he is out of commission at present.


  • #10
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    More


  • #11
    J Madone
    Registered Users, Registered Users 2 Posts: 623 ✭✭✭J Madone


    ROK ON wrote: »
    More

    Your missing a cover piece that threads in over this.its not meant to be removed, do you still have it? Has a 10mm allen key hole. I would say you can get a spare off a sram dealer


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  • #12
    The tax man
    Registered Users, Registered Users 2 Posts: 4,559 ✭✭✭The tax man


    I still reckon that thread is for a threaded cap(on left) that the main bolt pushes against to remove the arm.
    7278151884_1c9dcb7600.jpg


  • #13
    J Madone
    Registered Users, Registered Users 2 Posts: 623 ✭✭✭J Madone


    The tax man wrote: »
    I still reckon that thread is for a threaded cap(on left) that the main bolt pushes against to remove the arm.
    7278151884_1c9dcb7600.jpg

    Correct and right


  • #14
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    Guy
    Thanks plenty.

    What do I need to do now?
    Get a replacement part, insert it and then remove the crank arm?


  • #15
    clog
    Registered Users, Registered Users 2 Posts: 1,100 ✭✭✭clog


    You can get crank pullers that will work with a hollow spline. Cyclus ones certainly have a fitting for hollow isis/octalink splines. At a push I have had success putting a small coin in the space and using puller against that.

    This may work though as a replacement for the part you are missing.

    http://www.chainreactioncycles.com/ie/en/fsa-megaexo-crank-screw-qr-14/rp-prod87643


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