press fit BB grease

chatlow
chatlow Posts: 850
edited October 2016 in Workshop
Cube agree pro carbon frame, BB71 replaced with BB91. Would you guys grease the cups, the BB frame both or neither..? Also is lithium grease the best for this.

Thanks

Comments

  • keef66
    keef66 Posts: 13,123
    I think the general opinion is to fit them dry. Although my CR1 came with a factory fitted BB-71 and it had traces of green goo around it. Either way it's silent and smooth 3 years on.

    Any sign of grease when you took the BB-71 out? Any instructions with the BB-91? Shimano dealer manual doesn't mention grease for the press-fit BBs, but it does for the threaded ones.
  • antfly
    antfly Posts: 3,276
    Loctite 243 or similar, it prevents creaking.
    Smarter than the average bear.
  • Secteur
    Secteur Posts: 1,971
    edited October 2016
    I'd love a formal answer to this, since it comes up daily.

    A cannonade trained mechanic local(ish) to me said when they creak it's usually because they weren't greased when fitted.

    On here, the popular answer seems to be fit them dry.

    Others (including the manufacturers, inc cannondale!) say fit dry + loctite.


    I have only replaced the BB once on mine in the 3 years I have had it - about a year ago - and I fitted them dry (but immaculately cleaned, using isopropyl alcohol) and had no problems. But then it's Cannondales top end ("hi-mod") frame, so may be made to better tolerances than cheaper frames (?).

    I guess as a rule I'd fit dry. If it creaked, I'd re-fit it with grease. If it still creaked I'd then re-fit dry+loctitie. If that still didn't work I'd look for another BB solution entirely!

    EDIT - this edit in response to reply 2 posts below this - I am referring to steel BB30 bearings. Apologies.
  • arthur_scrimshaw
    arthur_scrimshaw Posts: 2,596
    I always understood that they should be greased (it's in the destructions and yes I know real men don't read them) - I've replaced a few (in a Boardman CX) and the only creaking I've had is from the NDS crank.
  • keef66
    keef66 Posts: 13,123
    Arthur Scrimshaw wrote:
    I always understood that they should be greased (it's in the destructions and yes I know real men don't read them) - I've replaced a few (in a Boardman CX) and the only creaking I've had is from the NDS crank.

    I'm thinking yours have been BB30 rather than the Shimano press-fit BB-71 / BB-91 which use plastic cups?
  • jermas
    jermas Posts: 484
    I always install them with silicone grease. It's inert so doesn't harm anything (carbon) and is perfect for plastic parts- waterproof too. Also, when you come to replace the cups, they're easier to extract.
  • chatlow
    chatlow Posts: 850
    yah, lots of mixed posts online and replies here saying fit with(out) grease. original BB71 did have grease on it but barely anything on the cups. This new 91 again has some grease on the inside but nothing on cups.

    Will fit and see how it runs. Cheap Icetools press works like a dream so can always re-fit with grease/loctite.

    Oh and when fitting - do you lot press one side in at a time or both together a same time? Again mixed opinions on this too.

    Final thing - the 4700 cranks have some grease but not a lot. Is it worth greasing the end of this where the left arm attaches and also some where it contacts the BB?


    Thanks a lot
  • Secteur
    Secteur Posts: 1,971
    one side at a time if the proper way to do it - this ensures they seat perfectly square.
  • Secteur
    Secteur Posts: 1,971
    chatlow wrote:

    Oh and when fitting - do you lot press one side in at a time or both together a same time? Again mixed opinions on this too.

    One side at a time to ensure they are squarely seated.
    chatlow wrote:
    Final thing - the 4700 cranks have some grease but not a lot. Is it worth greasing the end of this where the left arm attaches and also some where it contacts the BB?

    Yes - lithium type grease on the shaft (fnarr) and a bit of copper grease where the spindle end attached to the NDS crank arm never hurts (lithium grease ok too, as is not using any at all but a smear of grease always helps eliminate creaks)
  • chatlow
    chatlow Posts: 850
    gracias. Oh and silly question of the day - the plastic piece that connects the two cups together - what exactly does it do? just offer some strength/stability for the cups? I will plan to press one side in with this plastic bit then the other cup in afterwards.

    I have some multi purpose lithium based grease i can slap on. Cheap stuff called ep2 (triple qx) and some copper grease too. Hopefully they will suffice so I can get this finished up tonight :-)
  • Secteur
    Secteur Posts: 1,971
    As for the plastic tube - I actually don't know the specific purpose of that - but I would guess it's to keep frame-water away from the bearings?? A bit of useless knowledge but I'd like to know! Or maybe it's to stop the cups screwing too far together to keep the BB width accurate to the mm? Probably a bit of both!
  • chatlow
    chatlow Posts: 850
    Secteur wrote:
    As for the plastic tube - I actually don't know the specific purpose of that - but I would guess it's to keep frame-water away from the bearings?? A bit of useless knowledge but I'd like to know! Or maybe it's to stop the cups screwing too far together to keep the BB width accurate to the mm? Probably a bit of both!

    ^^ makes sense but be good to confirm for the bike geek in us!
  • arthur_scrimshaw
    arthur_scrimshaw Posts: 2,596
    keef66 wrote:
    Arthur Scrimshaw wrote:
    I always understood that they should be greased (it's in the destructions and yes I know real men don't read them) - I've replaced a few (in a Boardman CX) and the only creaking I've had is from the NDS crank.

    I'm thinking yours have been BB30 rather than the Shimano press-fit BB-71 / BB-91 which use plastic cups?

    Ah yes you're correct, different beast then!
  • keef66
    keef66 Posts: 13,123
    chatlow wrote:
    gracias. Oh and silly question of the day - the plastic piece that connects the two cups together - what exactly does it do? just offer some strength/stability for the cups? I will plan to press one side in with this plastic bit then the other cup in afterwards.

    I have some multi purpose lithium based grease i can slap on. Cheap stuff called ep2 (triple qx) and some copper grease too. Hopefully they will suffice so I can get this finished up tonight :-)

    If you read the Shimano dealer manual it says use the plastic tube if there are holes in the BB shell connecting to other frame tubes, but you can omit it if not. So I'm assuming it's to protect the bearings from possible water ingress.
  • dj58
    dj58 Posts: 2,223
    chatlow wrote:
    yah, lots of mixed posts online and replies here saying fit with(out) grease.
    Will fit and see how it runs. Cheap Icetools press works like a dream so can always re-fit with grease/loctite.

    I don't think you can remove a Shimano type pressfit BB without damaging the bearings and cups due to the method required to remove them.

    This is what Giant recommend for installation in a carbon frame.
    https://www.giant-bicycles.com/_upload_ ... 504_EN.pdf

    From the Park Tool website

    "NOTE: It is the intent of the bike manufacturers that the bottom bracket bearing be removed only when being replaced. It is necessary to impact the bearing adaptor and bearings from the inside, which may leave impact marks. Because a new bottom bracket is being installed, this is usually not a concern."
  • chatlow
    chatlow Posts: 850
    right so the BB fitted and 4700 crankset too. Initial thoughts were worrying as it was not spinning very freely. Loosened the plastic screw cap slightly and it has definitely improved, and may get better after a few rides.

    Will pray for zero creaks during ride tomorrow. Yeah i also heard that you shouldn't re-use the bearings unless you can remove them very carefully.
  • Secteur
    Secteur Posts: 1,971
    chatlow wrote:
    right so the BB fitted and 4700 crankset too. Initial thoughts were worrying as it was not spinning very freely. Loosened the plastic screw cap slightly and it has definitely improved, and may get better after a few rides.

    Will pray for zero creaks during ride tomorrow. Yeah i also heard that you shouldn't re-use the bearings unless you can remove them very carefully.

    If you're referring to the plastic cap with the star like key shape, that holds the NDS crank arm on, then this should only be finger tight - not torqued up. The two pinch bolts then do all the hard work (torqued up equally bit by bit - don't do one fully and then the other).
  • cycleclinic
    cycleclinic Posts: 6,865
    I have created another post with a fix I have used for my press fit BB. You'll be surprised.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • chatlow
    chatlow Posts: 850
    Well no creaks for me so thanks for all the advice on here.
  • Nick Payne
    Nick Payne Posts: 288
    I've used Loctite 609 (plus Loctite 7471 primer on the carbon BB shell) to cure creaking on several friend's bikes with press fit BBs.
  • fuel2000
    fuel2000 Posts: 65
    Nick Payne wrote:
    I've used Loctite 609 (plus Loctite 7471 primer on the carbon BB shell) to cure creaking on several friend's bikes with press fit BBs.

    As above, this was the way Canyon told me to fit the bb as well, used this method on quite a few bikes, never any creaks.

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