To grease or not to grease a square taper bottom bracket axle?

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  • To grease or not to grease a square taper bottom bracket axle?
  • bencooper
    Member

    <backs slowly away from the thread>

    Premier Icon granny_ring
    Subscriber

    Can of worms….

    You’ll find one or two old threads regarding that question on here. 🙂

    orangeboy
    Member

    I shall order another beer before this gets going.

    I don’t and have not as per Royce instructions
    But …….

    TurnerGuy
    Member

    no

    use the royce method of putting the crank on and torqueing, then ride it for some short bursts and keep retorqueing between each burst. Eventually it will not want any more torqueing.

    The aluminum of the cranck provides enough lubrication to move the crank onto the interference fit crank.

    Premier Icon richmars
    Subscriber

    No, in my view.
    The bolt brings the two tapers together to form an interference fit. Grease will only help to loosen it when not needed. When needed,the right tool has always worked for me.

    patriotpro
    Member

    Grease makes it a tighter fit so yes, grease.

    mrmonkfinger
    Member

    …awaits small flurry of inaccurate reasoning…

    use the royce method of putting the crank on and torqueing, then ride it for some short bursts and keep retorqueing between each burst

    so, you:

    1 do it up
    2 ride it, with it being too loose to be properly held on
    3 go to 1

    until it “stops being too loose”?

    utter barking tosh

    GrumpyDave
    Member

    Do I or do I not?

    khani
    Member

    Yes
    No
    A tiny bit
    Loads
    I say no,
    but the man from Del Monte he say yeeeeeeesss!!!…

    Finkill
    Member

    In reality it makes sod all difference,

    Potentially the crank will pull on a tiny bit further if the taper is greased, but so will over-torquing it.

    Follow the crank manufacturers torque setting and re-tighten after riding up and down the street a bit.

    reggiegasket
    Member

    this has been done to death and the answer is no.

    Premier Icon somafunk
    Subscriber

    runs into thread
    Don’t use grease, if anything at all use antiseize such as copaslip or Park Tools ASC-1 if you prefer overpriced bike specific antiseize and torque to manufacturers advice
    runs back out of thread with hands covering ears

    I’ve had conflicting advice from various sources such as blingy crank manufacturers and blingy bb manufacturers which has led me to discard any information received and believe in my own judgment, whether that be correct or not.

    I’ve a set of middleburn square taper cranks from 1993 still going strong on a royce BB, i used copaslip and a torque wrench.

    Premier Icon Clobber
    Subscriber

    I say yes, my middleburns and white industries cranks always loosen and loosen and loosen if they aren’t installed with a thin smear of grease…

    They then stay tight but also come off easily when required.

    Edit: I use copperslip, not grease, as per somafunk

    Premier Icon richmars
    Subscriber

    It’s all about getting the correct torque on the bolt. It may happen that you get the torque without the tapers being ‘correctly’ aligned, in which case copperslip or grease may help. It’s also possible that you get a good fit without help.
    I don’t use any and I haven’t had a problem.

    Sam
    Member

    this has been done to death and the answer is no.

    Don’t think so… Can’t believe there is still a need to link this after 23 years

    Don’t use grease, if anything at all use antiseize such as copaslip

    Both things will have exactly the same effect in this case – sorry Kenny.

    Premier Icon seadog101
    Subscriber

    Don’t use grease, if anything at all use antiseize such as copaslip or Park Tools ASC-1 if you prefer overpriced bike specific antiseize and torque to manufacturers advice

    What that man said^^. I’ve always added a wee dab (match head) of cheap antisieze. Never had a crank fall off or fail to come off when wanted.

    sweepy
    Member

    I put a smear of grease on, then wipe it off again. That way everyone’s happy.

    teddy
    Member

    Grease, i have fitted over 30 on my own bikes over the years all creak free and come off again easily ish.
    Dont blather it, just a brush on covering.
    Tighten as hard as you dare.

    Premier Icon oxym0r0n
    Subscriber

    New shimano square taper bbs come packaged with a little bit of lithium grease on the tapers… Just saying!

    TurnerGuy
    Member

    utter barking tosh

    I believe that is what Royce advise.

    mrmo
    Member

    i don’t grease as such, more thin smear of something. Pedals though!!! LOTS OF ANTI SEIZE, learnt the hard way.

    Premier Icon epicyclo
    Subscriber

    Anything I may want to remove later gets greased.

    TurnerGuy
    Member

    I have a titanium spindle on my BB and so if the crank is not fully on it will creak, whereas you don’t notice for a steel spindle.

    The Royce method I described is easily the best method as the crank is solidly on once you are finished retorqueing.

    Greasing the spindle is less successful long term.

    People also suggest that greasing pulls the crank on further than it should.

    soulboy
    Member

    No grease. Bolts under high torque stretch, so you can try the following technique: tighten the crank bolts to the recommended torque (e.g. 45 N m) with a torque wrench; slacken off and then re-tighten – you’ll find the wrench goes round a few more degrees than the first time; wait a short while and tighten again. Job done.

    bencooper
    Member

    Bolts under high torque stretch

    I highly doubt you’re taking the bolt past it’s elastic limit – and if you are you have problems.

    I’d guess what’s happening in your situation is that the aluminium crank is galling slightly on the steel axle, this then beds in slightly with the pedal oscillation, requiring further tightening.

    A dab of grease would prevent the galling in the first place.

    Dammit, got sucked in 😉

    soulboy
    Member

    I highly doubt you’re taking the bolt past it’s elastic limit

    You’re right: you’re not taking it anywhere near the elastic limit, you’re accounting for stretch that takes place before the limit is reached.

    bencooper
    Member

    I don’t understand – yes, the bolt stretches a fraction as you tighten it, but are you saying it stretches more with riding?

    soulboy
    Member

    don’t understand – yes, the bolt stretches a fraction as you tighten it, but are you saying it stretches more with riding?

    Because of the stretch, the bolt will loosen after initial tightening to below the original torque spec. By using the above technique, the bolt will remain at 45 N m and the cranks will not loosen subsequently.

    My understanding is that the use of grease causes the crank to slide further onto the taper than designed, deforming the crank/axle interface on the softer crank to a degree.

    trail_rat
    Member

    **** it . Just use carbon assembly paste 😉

    robinlaidlaw
    Member

    Because of the stretch, the bolt will loosen after initial tightening to below the original torque spec. By using the above technique, the bolt will remain at 45 N m and the cranks will not loosen subsequently.

    This, the stretch in the bolt will push the crank up the taper a bit more as it works, meaning that the tension in the bolt is reduced.

    I always used to wipe with a greasy cloth then tighten them right up, they stayed on, tight and creak free and came off again fine when required. The crank extractor threads just aren’t strong enough in many cranks to deal with pulling the crank off if they were dry and had corroded at all. Copper grease / anti-seize would also be fine.

    My understanding is that the use of grease causes the crank to slide further onto the taper than designed, deforming the crank/axle interface on the softer crank to a degree.

    I was always kind of depending on that. You’ll never get a better fit between the two parts than you get if you get a little compressive yielding on the contact faces of the crank. Machining tolerances mean that the only way you can guarantee full surface contact is to yield the crank slightly. In my opinion this is much more desirable than leaving it sitting on the high spots and vulnerable to fretting, the risk of splitting the crank is much smaller than the risk of ruining it by means of the taper being damaged as it moves on the axle if it isn’t really tight.

    bencooper
    Member

    Because of the stretch, the bolt will loosen after initial tightening to below the original torque spec.

    Yes, it loosens because the crank wiggles a little further up the axle.

    When you tighten the bolt, the system reaches an equilibrium where the tension of the bolt matches the friction and compression of the crank. But that friction is artificially high because of the galling of the aluminium, so the friction reduces with use, causing an equal reduction in the tension of the bolt – so you find you can tighten the bolt further.

    Remove that friction with grease, and then you’re left with the compression of the crank matching the tension of the bolt, which won’t loosen up and require retightening.

    deforming the crank/axle interface on the softer crank to a degree.

    Yup, that’s exactly what you want to happen. It’s not a friction fit, it’s a compression fit.

Viewing 31 posts - 1 through 31 (of 31 total)

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