FSA external bearing bottom bracket compatibilty.

Discussion in 'Cycling Equipment' started by swampy1970, Jun 19, 2008.

  1. swampy1970

    swampy1970 Well-Known Member

    Joined:
    Feb 3, 2008
    Messages:
    10,057
    Likes Received:
    185
    FSA state that only specific external bottom brackets may be used with each type of FSA crank.

    Is this just a 'paper' marketing ploy to stop people with a cheaper aluminum crank upgrading to a better bottom bracket or is there really an difference in each of the models of FSA bottom brackets?

    Or would I just be better off with calling Phil Wood and seeing if their new outboard bearing BB units are compatible instead. ;)
     
    Tags:


  2. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    SHIMANO Hollowtech-II BBs are interchangeable with FSA MegaExo BBs, and vice-versa.
     
  3. swampy1970

    swampy1970 Well-Known Member

    Joined:
    Feb 3, 2008
    Messages:
    10,057
    Likes Received:
    185
    Really? Cool.

    I got an email back from FSA tech support saying that each model of crank could only be used with the specific model of BB that the unit was sold with. They even have a rather sizable "compatibility chart" showing which cranks can be used with various BB's. :eek:

    www.fullspeedahead.com/downloadfly.aspx?download=downloads/Install_KForceLightCranks.pdf

    "Please Note: Specific models of FSA MegaExo cranks require specific models of FSA MegaExo BB’s"
     
  4. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    Well, I guess that what FSA "tech" people told you is similar to SHIMANO's marketing department declaring that you can only use Dura Ace "stuff" with other Dura Ace "stuff" ... Ultegra with Ultegra, 105 with 105, etc.

    The inner diameter of the bearings is the same 24mm (i.e., the diameter of the spindle for the Hollowtech-II & MegaExo cranks is 24mm).

    The inner diameter of the Campagnolo bearings is 25mm.

    The inner diameter of the GXP bearings is 25mm on the driveside & 24mm on the non-driveside -- those wacky guys obviously think they have a better idea.
     
  5. Phill P

    Phill P New Member

    Joined:
    Jul 9, 2006
    Messages:
    513
    Likes Received:
    0
    Newer model shimano bearings use the same as campy - a non standard 25 37 6 bearing (instead of 7mm width). For some reason Shimano swapped from the standard 7mm bearing to a 6mm bearing around 2004.
    FSA and race face still use the 7mm bearing.

    I think the Shimano axel is 24mm OD, and they use a shim to get to the 25mm ID bearing.

    I have no idea if these BBs really are all interchangable, but I've heard they all have slightly different total installed widths, and need to be adjusted with a few shims. This is normal even when using a DA BB with a DA crank due to frame shell width etc.

    The truvative/scram BBs I believe are not interchangable due to the NDS bearing being pinched between the crank arm and axle to obtain the lateral adjustment instead of loading both bearings. In my mind this is a better design than preloading the bearings with an axial load. Plus all the lateral loads are delt with on the NDS which sees lower radial loads. However I've not heard good things about the GXP BBs (but I'm happy to be corrected!)
     
  6. swampy1970

    swampy1970 Well-Known Member

    Joined:
    Feb 3, 2008
    Messages:
    10,057
    Likes Received:
    185
    I had a good chat with the folk at Phil Wood today and a nice stainless outboard bottom bracket is heading my way. A little heavier - but all the Phil stuff I've seen has been amazingly simple and really well machined.

    Interestingly they're dropping their ceramic bearings in favor of something smoother and longer lasting..... and way less expensive.
     
  7. SkiierBiker

    SkiierBiker New Member

    Joined:
    Nov 10, 2009
    Messages:
    1
    Likes Received:
    0
    Hi Guys, Its not marketing. Regarding the FSA BB Shell question. the SL-K Force Light (carbon cranks) set up is different then the FSA alloy cranks. The BB Shell width is narrower by 2 mm for carbon cranks vs. alloy cranks.

    At this time I'm trying to figure out if the Phil Wood or Chris King BB work with FSA carbon cranks.

    I have searched the whole country for FSA BBs and all the English threads are no stock. I may just get a bearing at Boca Bearing and rebuild. I am pretty unhappy at the very short life of my FSA BB.

    Has anybody out there used a Phil Wood BB with a FSA carbon crank set? Thanks.
     
Loading...
Loading...