Press-fit BB cups - loctite, grease or nothing?

neeb
neeb Posts: 4,467
edited September 2013 in Workshop
What's the consensus on what to use when banging in press-fit BB cups? A lot of people recommend loctite, but I also read that another approach is to use grease, on the assumption that tiny movements will happen anyway and grease will stop this causing squeaks..

In this case it'll be Campagnolo BB86 adapters in an all-carbon BB shell (no metal insert in the shell). The campag instructions don't mention using any substance.

Comments

  • The Mechanic
    The Mechanic Posts: 1,277
    I have just bought a new carbon bike with a BB30 BB. I have not had any previous experience of these so looked it up. Apparently, grease is recommended.
    I have only two things to say to that; Bo***cks
  • sungod
    sungod Posts: 16,530
    check frame maker's instructions, do what they say, otherwise...

    if tolerances are ok, grease is all you'll need

    if the bearing seat tolerance is bad or the shell distorts under load, use loctite retaining compound 641 or 609, primer 7649 or 7088 will speed cure time
    my bike - faster than god's and twice as shiny
  • desweller
    desweller Posts: 5,175
    I'd be tempted to stick the bearings in the freezer for a few hours, then mount them into the frame with a clamp across the BB shell to stop them coming adrift.
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  • bikeit65
    bikeit65 Posts: 982
    I recently replace the bearings in a Caad 10 which had a BB30 bottom bracket i used grease, no problems here, i thought grease was a no-no with carbon fibre.
    https://www.instagram.com/seanmcgrathphotography/
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    Cannondale CAAD 10 2012.
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  • bernithebiker
    bernithebiker Posts: 4,148
    Sworks BB cups were just press in.

    But Specialized changed their minds and issued small packets of epoxy resin to glue them in.

    My LH cup was always nice and tight, but my RH one would just fall out when I disassembled the crank, so the glue has sorted that.

    Not very pro though.......
  • sungod
    sungod Posts: 16,530
    Bikeit65 wrote:
    I recently replace the bearings in a Caad 10 which had a BB30 bottom bracket i used grease, no problems here, i thought grease was a no-no with carbon fibre.

    it's an urban myth, if you check the compatibility there's no issue - which does make sense, imagine all the oil and grease that cf on a bike is exposed to!
    my bike - faster than god's and twice as shiny
  • neeb
    neeb Posts: 4,467
    Thanks for the replies - as I couldn't find a reference to grease in either the Campagnolo instructions or the frame maker's instructions, I have just pressed them in dry. I'll see how it goes, if they start squeaking I might refit them with grease. Some of the Campagnolo documentation (although not most of it) mentions using loctite if necessary, but you have to use one of two particular types and they also need some sort of priming compound. I'll leave that as a last resort if I start having problems..

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