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FSA Gamma Pro Mega Exo crank removal

CarveCarve Posts: 8
edited January 2019 in MTB workshop & tech
Hi folks.

I recently bought a boardman 8.9 mht and would like to change the chainring from a 32t to a 34t. I am a bit confused with what i will need to remove the crank.

This is the bike > ... iewDetails

I think i just need this > ... :rk:6:pf:0

Could someone confirm that for me please?

Also wondering if i need to remove the non drive side first or if i can just remove the drive side?

And if there is a PDF manual for this setup anywhere? ive found lots of manuals on FSA website but cant find the correct one.


  • JBAJBA Posts: 2,721
    Isn't it a self-extracting jobbie?
    Undo the 8mm bolt on the non-drive side and the crank should easily come off the splines. The other side should then slide out. (It may require a tap with a rubber mallet.)

    Check this video. It's for a road bike but the principle is the same.

    You may be able to change the chain ring without removing the crank set though. Undo the four bolt holding the ring on and then carefully pass it over the crank.
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  • keef66keef66 Posts: 13,123
    Second the suggestion of just removing the chainring bolts and see if the ring will wriggle over the spider / crank.
  • CarveCarve Posts: 8
    Thanks im going to have a proper look at it in the morning.
  • Vino'sGhostVino'sGhost Posts: 4,129
    how did you get on?

    Id be tempted to remove the crank completely to replace rings. its usually straight forward and means i dont have to work bent over like a kid under a loom.

    Also you can give it a proper clean when its off the bike
  • keef66keef66 Posts: 13,123
    Me too, especially with road chainsets with 2 or 3 rings. A lot easier to clean everything up and get at both sides of the chainring bolts with the thing clamped in a workmate.

    But quickly swapping a single ring on a MTB I might be tempted to do it in situ
  • CarveCarve Posts: 8
    how did you get on?

    Finally got round to doing it this morning. It came off really easily without removing the crank. Took less than 10 mins. The bike is new its done less than 100 miles so didnt really need to clean anything up.

    Thanks for the advice all.
  • Vino'sGhostVino'sGhost Posts: 4,129
    nice work
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