FSA crank problem, advice needed

nasha48
nasha48 Posts: 231
edited June 2017 in MTB workshop & tech
Hi guys. Crank problem. Its an FSA MegaExo on my Boardman FS Pro and, for no obvious reason the drive side crank just keeps on coming very loose to the point of almost falling off. I tighten up the 10mm allen bolt (very tight), ride 5 miles, have to do it again. This has obviously started to have an effect on the cartridge bearing too. Do i try some loctite on the crank bolt thread or is there something else the likely culprit?

Comments

  • The Rookie
    The Rookie Posts: 27,812
    Once it's ridden loose the splines wear and will no longer hold it tight and it will very readily work loose again.

    The only proper fix is new cranks, but using some bearing lock between axle and crank arm to stop it moving and loosening the bolt sometimes works.

    FSA cranks are pretty poor anyway!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • nasha48
    nasha48 Posts: 231
    Cheers Rookie. Makes sense about spline wear now you've said it, has somewhat disappointed me though! Off to Forest of Dean next week for few days so unlikely I'm going to get time to resolve. I say this as its still under warranty but no way Halfords could sort it in time i think. Hence, I'm after a temporary fix to get me through. Not confident though and concerned about it wrecking the occasion somewhat.

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