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FSA Mega Exo Chainsets / Bottom Brackets

hondicusphondicusp Posts: 168
edited January 2011 in Workshop
Have just entered the wonderful new world of external BB bearings by ordering a FSA Energy MegaExo chainset. My question is, with regards to a Bottom Bracket to run with is this,is MegaExo an FSA standard and therefore are MegaExo components all compatible? ie. can I buy any FSA MegaExo BB and it'll work fine? Also what's the score with using other brand BB's? Do all systems run on a standard diameter axle? Help


  • emerywdemerywd Posts: 52

    Having fitted bottom brackets & chainsets from Shimano, SRAM (ie truvativ)and FSA on a number of MTBS and road bikes, I've concluded that Shimano kit is just built better.

    Whether that's down to higher machining tolerances or different designs I dont know. But, in my experience you can fit an FSA bottom bracket easily enough, put the chainset on and there's play. Repeat the process several times and you'll eventually get it on without any play not having understood what you did differently. Truvativ is slightly better, but still not great.

    Shimano, fits on first time perfectly.

    I wouldn't buy an FSA chainset unless it was heavily discounted (often the case from CRC), in which case I'd be prepared to put up with inconvenience, Afterall, you don't change the BB that often.

    As for Campy - only ever had one bike with campy (chorus) on it and the chainset fell out (second ride on a new bike) whilst I was riding it, resulting in a crash. This was NOT due to Campag kit, but rather the piss poor installation from a well known northern online bike retailer. All the splines on the Chorus chainset were mashed ... They'll remain nameless, as they offered a full refund for the bike. Although, they did resell it on their web site a week or two later as 'shop soiled' ... anyway, I digress.

    Stick with Shimano, over FSA unless it's a steal
  • emerywdemerywd Posts: 52
    .. and as far as I know, stick with FSA Mega Exo brackets for the chainset. Although I believe the Shimano BB tool is compatible??
  • emerywdemerywd Posts: 52
    .. and as far as I know, stick with FSA Mega Exo brackets for the chainset. Although I believe the Shimano BB tool is compatible??
  • hondicusphondicusp Posts: 168
    It was a steat ( and it was from CRC :) )

    Thanks for the input.

    Er... so can I use a Shimano BB with the FSA chainset or do I have to stick with FSA BB's?

    Apologies for being thick
  • hondicusphondicusp Posts: 168
    Cheers, got my timing wrong there
  • emerywdemerywd Posts: 52
    No worries. Sure, it'll work great once installed and you might get it on first time!

    Just dont get too frustrated if it doesn't, it will eventually. Never had any problems with mine once installed!
  • Monty DogMonty Dog Posts: 20,614
    FSA say that there are different models of MegaExo BB and the need to be matched to the cranks, but IME you can fit Gossamer cranks to a HTII BB no problem. I've also had no problems running SLKs with the 'wrong' BB - sometimes it's just a case of trying it out. My experience of all external BB's is that they are all pretty bad, and some are worse than others for things like durability and weather-resitance. The orginal Truvativ GXP/SRAM in particular was a pile'o'censored with newer ones better sealed.
    The only blessing is that they all use a similar pattern of fitting tool, but for some stupid reason the Truvativ torque wrench adaptor has too big a chamfer to work with others - best get a 'flat-spanner' type as there's less risk of slippage.
    Make mine an Italian, with Campagnolo on the side..
  • hondicusphondicusp Posts: 168
    Hmmm............remind me what the advantages of external bearings are again :?
    Users dont appear overimpressed
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