Sram PF30 to FSA

wahla21
wahla21 Posts: 96
edited July 2017 in Workshop
Hi guys,

I have a Boardman Team Carbon with a SRAM Apex groupset and PF30 BB.
I am converting to Shimano 105 and have a FSA crankset.

Can I use existing BB with the new FSA crankset or do I have to buy a new BB?
The FSA one is a MegaExo crankset with 24mm spindle and if I\m not mistaken the SRAM Apex one is 24mm too, right?

Any help is much appreciated!

Comments

  • sungod
    sungod Posts: 17,338
    the sram apex crankset will be gxp (24/22mm)

    i.e. the existing bb will not match fsa megaexo crankset
    my bike - faster than god's and twice as shiny
  • wahla21
    wahla21 Posts: 96
    Thanks.
    So I assume I need a FSA PF30 BB?

    Something like this: http://www.wiggle.co.uk/fsa-pf30-road-bottom-bracket/?curr=GBP&dest=1&prevDestCountryId=14
  • sungod
    sungod Posts: 17,338
    that looks like one for 30mm spindle

    i'm not really familiar with megaexo, but i think you need to check the exact model of crankset to see which bb is correct for it, try fsa website at starting point
    my bike - faster than god's and twice as shiny
  • joenobody
    joenobody Posts: 563
    FSA MegaExo is equivalent to SRAM GXP so you should be good to go with the existing BB.
  • sungod
    sungod Posts: 17,338
    JoeNobody wrote:
    FSA MegaExo is equivalent to SRAM GXP

    no it isn't
    my bike - faster than god's and twice as shiny
  • StillGoing
    StillGoing Posts: 5,211
    The Apex crankset is better than the FSA one if its a Gossamer anyway.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • joenobody
    joenobody Posts: 563
    sungod wrote:
    no it isn't
    No? Care to elaborate? That was my understanding based on the research I did over the winter - aren't they both 24mm diameter, 90mm width formats? Same as Shimano's Hollowtech II...

    Some further investigation suggests that SRAM have tapered axles, so while the format is broadly similar, the exact spec is different. You could probably get away with the same cups, but would need the right cartridge, so you're probably better off just getting the matching BB from your crank manufacturer, or a specific 3rd party BB.
  • wahla21
    wahla21 Posts: 96
    philthy3 wrote:
    The Apex crankset is better than the FSA one if its a Gossamer anyway.

    Yeah might keep the apex one as this BB business is a proper mind field!

    Thanks everyone for your contributions
  • StillGoing
    StillGoing Posts: 5,211
    JoeNobody wrote:
    sungod wrote:
    no it isn't
    No? Care to elaborate? That was my understanding based on the research I did over the winter - aren't they both 24mm diameter, 90mm width formats? Same as Shimano's Hollowtech II...

    Some further investigation suggests that SRAM have tapered axles, so while the format is broadly similar, the exact spec is different. You could probably get away with the same cups, but would need the right cartridge, so you're probably better off just getting the matching BB from your crank manufacturer, or a specific 3rd party BB.

    They're completely different. A bike I built up I stripped out the FSA Gossamer BB386 ME to replace with a SRAM Red gxp crankset. The two are not compatible. You also need a different BB spanner for the BB386 ME if threaded. They look similar, but aren't. I also had to remove a PF BB386ME from my main bike to fit a Rotor PF 4624 to take a 3D24 crankset.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • sungod
    sungod Posts: 17,338
    JoeNobody wrote:
    sungod wrote:
    no it isn't
    No? Care to elaborate? That was my understanding based on the research I did over the winter - aren't they both 24mm diameter, 90mm width formats? Same as Shimano's Hollowtech II...

    Some further investigation suggests that SRAM have tapered axles, so while the format is broadly similar, the exact spec is different. You could probably get away with the same cups, but would need the right cartridge, so you're probably better off just getting the matching BB from your crank manufacturer, or a specific 3rd party BB.

    the axle is not 'tapered', it is stepped, the nds is 22mm and is axially clamped to the nds bearing

    hollowtech is 24mm, not stepped, it is too big to get through the nds bearing of a gxp bb

    it's not only the bearing, the nds bb outer cover is also gxp specific, the cup bearing seat depth may also be different due to the increased depth of the gxp inner race
    my bike - faster than god's and twice as shiny
  • joenobody
    joenobody Posts: 563
    Thanks for the clarification. It seems that just as I was getting my head around BBs things are still not as clear cut as I thought :)

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