Home Forums Bike Forum Fitting a square taper crank/BB- is this right?

  • This topic has 36 replies, 21 voices, and was last updated 9 years ago by DezB.
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  • Fitting a square taper crank/BB- is this right?
  • hora
    Free Member

    The crank doesn’t seem to sit far enough down the BB. The BB seems to taper so the crank arm cant fit down any further – is this right/correct or is there a different BB I need? (Cranks are Sugino tracks).

    cchris2lou
    Full Member

    There are 2 different standards of square taper bb.

    Look on Sheldon Brown website.

    tragically1969
    Free Member

    They pull a fair way on when you get them torqued up, looks OK to me.

    warpcow
    Free Member

    Looks alright to me.

    swillybey
    Free Member

    Thats pretty normal with new cranks, if they sat all the way on the crank first go the taper would be pretty useless and would be wobble central.

    the-muffin-man
    Full Member

    Look fine to me too.

    jimfrandisco
    Free Member

    yep – as ^^ they said. Looks perfectly normal.
    Only thing i’d add is to make sure you get some copper grease on there or they’ll be impossible to get off after some time.

    No idea if that’s the recommended practice or not so preparing to be flamed, but it’s always worked for me.

    cynic-al
    Free Member

    No need for grease etc on tapers ime but no harm either.

    Cranks pull on 3mm or so when tightened.

    DO grease BB threads

    cliffyc
    Free Member

    Look absolutelely spot-on fit,no need to worry. Just check them for tightness after a few rides and you are set. If they had hit the base of the taper I would be worried but this fit is normal for Shimano BB. Enjoy the ride. 🙂

    gonzy
    Free Member

    as said above they look fine.
    agree with cynic-al about not greasing the tapers and greasing the cups.
    if you’re worried about the crank bolts working loose then apply a very small dab of threadlock on them.

    swillybey
    Free Member

    Worth keeping an 8mm on you to tighten them up after the first couple of rides.

    hora
    Free Member

    Cool – cheers chaps 😀

    Now I need to find a quill stem. All are the same diameter?

    bigyinn
    Free Member

    Normally 1 1/8″, but some may be 1″

    TurnerGuy
    Free Member

    Torque them up, go for some sprints up and down the road, then torque them again, then sprint again, and repeat until they keep the torque.

    Then check again after each ride for a while.

    And no grease on them.

    hora
    Free Member

    Ah definitely 1″ then- this is an old school CIOCC(?) steel frame/fork.

    DezB
    Free Member

    I’ve got a 1″ quill and carbon fork to go with it you can have for postage price. Just hung up in my garage, not sure how nice you want…

    Stevet1
    Full Member

    Torque them up, go for some sprints up and down the road, then torque them again, then sprint again, and repeat until they keep the torque.

    Then check again after each ride for a while.

    And no grease on them.

    I don’t think this is right. Both the grease thing and the re-tightening thing. A thin layer of grease allows the crank to be properly torqued. After riding the cranks move up the BB axle slightly and away from the bolt giving the impression that the bolt needs to be re-tightened when in fact the cranks are finding their correct position on the BB axle. repeated re-tightening chases the crank further and further onto the axle until it splits.

    See here for better explanation-
    http://sheldonbrown.com/brandt/installing-cranks.html

    hora
    Free Member

    Yes please 🙂

    Do I need an external h/set – theres one fitted (will take a pic at lunchtime).

    I’ve naughtily been commuting into work on my pride and joy and the condition its in after just two days is 😯

    mintimperial
    Full Member

    Ooooh, I’ve not seen a good old “should I grease my square-taper or not” argument for ages, brilliant. 😀

    Here’s my 2p: doesn’t matter so long as you torque the things up properly, do what you like. Next!

    DezB
    Free Member

    Yes please

    Was that to my offer? I’ll have to get you pics and measurements later if so. Gotta make sure it’s long enough, like.
    There’s a Dura Ace headset in the frame too… been in there for yonks, but might be ok!

    hora
    Free Member

    Cheers/yes 🙂

    I’ll take a couple of pics of mine (and measure headtube length)- just to be sure you’ll think it’ll work.

    DezB
    Free Member

    Cool 🙂

    bencooper
    Free Member

    I don’t think this is right. Both the grease thing and the re-tightening thing. A thin layer of grease allows the crank to be properly torqued.

    Yup. Thin wipe of grease, torque on properly, job done.

    Stoner
    Free Member

    also – If you ever have the urge to bling it up with some allow crank bolts, use steel bolts to torque the crank on the tapers, then remove the bolts and fit the aluminium ones. Dont try to torque up with the aluminium ones.

    bigyinn
    Free Member

    DezB, just make sure he doesn’t try and return them due to lack of travel……

    bigyinn
    Free Member

    Aluminium crank bolts? Nope, soft as cheese, avoid.
    They’ll corrode onto the steel axle then when you try and undo them they either shear or round out.
    At least they’re easy to drill out.

    hora
    Free Member

    Here it is:

    I couldn’t find a measuring tape so slapped something for perspective next to it- I’d say its quite a short headtube.

    Rockhopper
    Free Member

    Shimano square taper chainsets come pre greased.

    mrmo
    Free Member

    Is that an Italian bottom bracket? Ciocc I think do not use bsa threads.

    simon1975
    Full Member

    With some nice grease inside I bet that headset will feel smooth and buttery; no need to replace!

    Fork could do with a drop of paint..

    bigyinn
    Free Member

    Rockhopper – Member

    Shimano square taper chainsets come pre greased.
    Probably to prevent corrosion in the box whilst it sits on the shelf.

    hora
    Free Member

    Is that an Italian bottom bracket? Ciocc I think do not use bsa threads.

    Will gently check tonight.

    TurnerGuy
    Free Member

    I don’t think this is right. Both the grease thing and the re-tightening thing. A thin layer of grease allows the crank to be properly torqued.

    Yup. Thin wipe of grease, torque on properly, job done.

    The no-grease and sprint/retorque thing is from the Royce bottom bracket installations here :

    http://www.sjscycles.com/Instructions/Royce/Royce_Titanium_Bottom_Bracket_Instructions.pdf

    and I tend to think they are right. The aluminum of the cranks with provide enough lubrication to pull the crank up the taper, especially using these instructions.

    Rockhopper
    Free Member

    bigyinn – Member
    Rockhopper – Member
    Shimano square taper chainsets come pre greased.

    Probably to prevent corrosion in the box whilst it sits on the shelf.

    Its a big glob of grease on one side of the square hole perfectly placed to be spread around when its placed onto the BB.

    TurnerGuy
    Free Member

    Its a big glob of grease on one side of the square hole perfectly placed to be spread around when its placed onto the BB.

    big glob of grease and ‘lightly grease the tapers’ are somewhat in opposition…

    Anyway – Royce ship titanium axles and I don’t think Shimano do, so I would go with the Royce instructions as getting a creak free fit with titanium axles is a lot trickier.

    gavinpearce
    Free Member

    I usually find it helps to have the BB in the bike first as I think it will be really difficult to install the BB now. 😆

    DezB
    Free Member

    Oh, Italian BB has been mentioned! I’ve got one in my frame but its…. HTII …

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