FSA Bottom bracket help.

triantri
triantri Posts: 11
edited June 2012 in Workshop
My FSA BB-6000 bottom brackets keep wearing out so Id had a mission to find a replacement.

First I bough a Shimano Tiagra and also an Ultegra bottom bracket to try on two bikes. Although they are for 24mm cranks the FSA is very tight and have to use a soft hammer to get the cranks on and a nightmare to take off!
I measured the bearings....
FSA bearings (original) 24.07 mm
Shimano bearings 24.00 mm
My FSA cranks are 24.07 mm thus thats why all the shimano ones are tight!

I then got a Hope ceramic unit and this was also tight, these also measure 24.00mm.
My Shimano cranks slide on the Shimano and hope BB's but the FSA's are so tight.

The FSA is an SRM so Im not wanting to use a hammer but want to find a BB that fits and last longer than 6 months!
So I was just after some advice really...

I can run a half round file up the shimano BB's as they have plastic sleeves, take off 0.07 of a mm and they'll fit fine.
I could find a replacement bearing for the Hope but the bearings I have are already 24mm so I think it would just be the same.
OR
I could lightly carefully reduce the diameter of the 24.07 cranks on the FSA SRM :-/

Ideally I want a BB that I can replace the bearing myself to save money but so far iv spend a bit looking for it! Should of just kept buying FSA rubbish BB-6000's :-/

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    0.07mm is an acceptable interference fit - a nudge with a rubber mallet is acceptable for new parts, it's only when you're using a 4lb club hammer that you might need to reconsider. In terms of your cranks, do they have carbon or alloy crank arms? If carbon, you need an 8000 series MegaExo BB which is slightly narrower than the 6000 series / Hollowtech 2 and probably explains why it's too tight.
    Make mine an Italian, with Campagnolo on the side..
  • nicklouse
    nicklouse Posts: 50,675
    is it stiff to fit on the first cup or only when going through the second?

    and dont file anything.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • triantri
    triantri Posts: 11
    The cranks are alloy cranks arms and its tight on the first cup and also the same on the second.
    So I guess ill fit the Hope BB's then and make it fit!. Was just alarmed as compared to the original BB6000 they are pretty tight and a nightmare to remove, especially with the sensitive nature of the SRM I did not want to shock it to much.... I have a hide hammer and still have to hit it pretty hard to get on - its not just a tap but a belt! Then use the securing pre-loading screw to wind the cranks on fully!
    Was a little worried that after being fitted for a few months that with such a tight fit they'll get stuck being so tight.
  • nicklouse
    nicklouse Posts: 50,675
    triantri wrote:
    The cranks are alloy cranks arms and its tight on the first cup and also the same on the second.
    So I guess ill fit the Hope BB's then and make it fit!. Was just alarmed as compared to the original BB6000 they are pretty tight and a nightmare to remove, especially with the sensitive nature of the SRM I did not want to shock it to much.... I have a hide hammer and still have to hit it pretty hard to get on - its not just a tap but a belt! Then use the securing pre-loading screw to wind the cranks on fully!
    Was a little worried that after being fitted for a few months that with such a tight fit they'll get stuck being so tight.
    sounds totally normal.
    if it was getting tight on the second bearing i would suggest getting the BB shell faced.

    the External cranks can be a bit of a fit. so much so many people end up fitting them incorrectly.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • triantri
    triantri Posts: 11
    Thanks you - feel a bit more at ease now while sledge hammering it in place ;-)
  • triantri
    triantri Posts: 11
    OK.....
    Removed shimano BB and cranks and fitted Hope BB onto bike.
    Fitted FSA SRM onto first cup with a tap (more than a tap) - It would NOT got past the 2nd cup so wound the bolt in like a bearing pull but then proceeded to strip the aluminium thread.
    I could not then get the cranks out - had to remove the none drive side cup from the bike with the crank still attached and the same on the drive side as I could not get the bearing off the FSA axle.
    I have not got a Hope BB cup stuck fast onto the axle and requires a bearing puller to remove it - plus I hope the SRM is not damaged with the hitting!

    Bottom line - if you have FSA and other BB don't fit - get the FSA BB even if they are poor!
  • giropaul
    giropaul Posts: 414
    If you are wearing out bearings rapidly are you sure that the frame is faced up correctly? External brackets are very sensative to this.

    They also seem sensative to wet weather, and don't last long if you ride in the rain.
  • desweller
    desweller Posts: 5,175
    Hope actually told me not to buy one of their BBs for my FSA crankset as the inner diameter of the bearing is too small. Although 0.07mm is an interference fit, which is usually a good thing for bearings, the installation methods open to you are very limited unless you have a lot of specialist tools; you risk damaging the bearings and / or crankset and, as you've discovered, disassembly is not straightforward either.

    You can get replacement bearings for the FSA cups from UKBikeStore...the design of the dust seal is not great, which is how water gets into the bearing unit, so it's worth reassembling your own BB cups using the bits and pieces from your dead BB. I've reassembled mine with liberal quantites of bearing grease in the seals to keep the water out. If I had some silicone grease in my shed I'd have used that...it would be perfect.

    69032-2.jpg

    HTH.
    - - - - - - - - - -
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  • triantri
    triantri Posts: 11
    Wow that's great thanks :-)
  • triantri
    triantri Posts: 11
    One more question - none of my cranks or bearings use the wave washer or spindle seal? I dont think iv even had them when getting a new BB! What are these and whats the function of them?