FSA loose crank

pylwagl
pylwagl Posts: 35
edited February 2017 in Workshop
I have a 2012 Tarmac with a FSA SLK crankset. on my way home tonight I noticed some play in the non-drive side crank ( It felt like a loose cleat at first). At home I checked it out and discovered side to side play - i.e. not in the direction of pedal rotation. The retaining bolt was a little loose, but having tightened it up I cannot eliminate the free play. I cant imagine that the splines have become damaged in 5 miles of gentle riding, they look fine, so what am I missing?
TIA
Stu

Comments

  • sungod
    sungod Posts: 17,340
    you're certain it's the crank-spindle junction where the play is? rather than the entire crankset being able to move slightly side to side?

    if it's definitely the crank that is loose on the spindle i'd remove it and inspect carefully, clean threads etc.

    also look at the installation instructions for the specific model and check that the correct bits are all there, if it uses shims to fine-tune spacing then maybe damage/wear has taken it's toll and you need to replace/add to get it right, or bearings might be worn/damaged, etc. etc.
    my bike - faster than god's and twice as shiny
  • Matthewfalle
    Matthewfalle Posts: 17,380
    Is it a model with a pre-load setting bolt?das Hound is asleep on me so can't get to the garage to look at mine to check.
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • pylwagl
    pylwagl Posts: 35
    so... have just had another look. the bottom bracket is good, its definitely movement at the crank/splines interface. no parts are missing. This pic shows the inner 16mm allen bolt and also the outer ring. is the outer ring a clamping device that can be tightened to hold the crank, or is the carbon bonded directly to it? I suspect the carbon has de-bonded from the metal ring since this is where the play is.
    any ideas?
    [img][/img]IMG_1206.jpg
    cheers
    stu
  • crankycrank
    crankycrank Posts: 1,830
    The outer ring with the 6 holes needs to be screwed in all the way (can't tell from the photo if it is or not) or the crank bolt may not be able to bottom out on the crankarm and hold it in place.
  • sungod
    sungod Posts: 17,340
    it's a self-extracting assembly

    when you are removing, the flange on the inner bolt pushes against the outer ring to force the crank away from the spindle

    when you are fitting, there's no load on the outer ring, the flange on the bolt inside instead presses the crank onto the splines

    might be best to remove it all so you can inspect the crank and check for any damage

    pic of similar self extracting bits...

    fsa-megaexo-self-extracting-crank-bolt-road-m18-k-force-sl-k-390-2060-5974-p.jpg
    my bike - faster than god's and twice as shiny
  • pirnie
    pirnie Posts: 242
    As above, that outer ring is a self extractor that allows you to remove the crank by loosening the centre bolt which pushes the NDS crank arm off against the spindle. Hopefully taking the crank off, screwing the self extractor all the way in and reassembling will fix it, however, if it doesn't it may be a bigger issue

    I can't tell from the photo exactly which crank this is, but I had a problem with a FSA SL-K carbon crank, where there was play in the non-drive side crank arm (on approximately a 6 month old bike). LBS and myself couldn't diagnose it and so it was sent back to FSA who (after about 3 months of back and forth) decided that it was due to the metal insert in the NDS crank becoming unbonded from the carbon crank arm.

    My crank was replaced by a brand new one under warranty but on a 2012 bike, I don't know if that will be possible. Still might be worth hitting the bike shop you bought it from to see if they can help if it is a manufacturing defect?

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