Press fit bb - grease, carbon paste or nothing?

rafletcher
rafletcher Posts: 1,235
edited March 2014 in Workshop
About to install my first press fit bb into a carbon frame. Bb she'll is carbon too, no metal inserts. So do I grease it before assembly, or use carbon assembly paste, or assemble it dry?

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Anti-seize rather than grease
    http://www.wiggle.co.uk/shimano-anti-se ... 5360507769
    Make mine an Italian, with Campagnolo on the side..
  • jermas
    jermas Posts: 484
    No grease or anti seize. Sometimes I use pure silicone grease. It's inert so doesn't react with anything.
  • desweller
    desweller Posts: 5,175
    The correct Loctite.
    - - - - - - - - - -
    On Strava.{/url}
  • 964cup
    964cup Posts: 1,362
    Clean it with Loctite 7063 (both press-fit cups and BB shell) then apply a thin coating of Loctite 603 to the mating surface of the press-fit cups. Both are available from Amazon for a few quid, or your local motor factors.
  • jermas
    jermas Posts: 484
    Loctite 603 isn't recommended for use on any plastics (where it can cause stress cracking). Shimano press fit bb's are in a plastic body, so I'd not want to use it there. Not too sure I'd use it on a carbon shell either. Also it's a high strength adhesive so probably best not using it on carbon.
    Holding press in steel bearings in a steel or aluminium shell it would be ideal.
  • rafletcher
    rafletcher Posts: 1,235
    I emailed Hope technical about this (as it's their BB I'm using) and they said they just use a medium weight grease. I think I'll give Primera a ring, as I bought the frame from them, and they also build them up into bikes, and see what they say.
  • 964cup
    964cup Posts: 1,362
    jermas wrote:
    Loctite 603 isn't recommended for use on any plastics (where it can cause stress cracking). Shimano press fit bb's are in a plastic body, so I'd not want to use it there. Not too sure I'd use it on a carbon shell either. Also it's a high strength adhesive so probably best not using it on carbon.
    Holding press in steel bearings in a steel or aluminium shell it would be ideal.
    Interesting. It's being recommended by Cervelo for the standard (plastic-shelled) SRAM PF30 BB in their BBRight frames. I have used it in my R3 with a Rotor (alloy-bodied) BB30 to 24mm converter, and in my S5 with the SRAM BB. I'll keep an eye out for stress cracks then. I believe it's marketed as a medium-strength adhesive, though.
  • rafletcher
    rafletcher Posts: 1,235
    Well primera agree with Hope - some lubrication is necessary, so I went out to our workshop and got some copaslip type grease. That's this evenings little job then (the BB assembly tool and BB arrived this morning)
  • curium
    curium Posts: 815
    rafletcher wrote:
    Well primera agree with Hope - some lubrication is necessary, so I went out to our workshop and got some copaslip type grease. That's this evenings little job then (the BB assembly tool and BB arrived this morning)

    I may be wrong but I think copaslip 'grease' is not a grease it's an anti-seize compound that helps prevent fixings becoming stuck to each other through corrosion.
  • rafletcher
    rafletcher Posts: 1,235
    Technically you're correct of course :-) and I call myself a mechanical engineer. :D

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