Square taper BB

The Rookie
The Rookie Posts: 27,812
edited October 2012 in MTB workshop & tech
What thread is the standard crank retaining bolt, trying to help a friend remove the BB and the previous owner has mullered the spline pattern somewhat so I want to buy a bolt to lock the BB tool in place.
Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

Comments

  • Uli
    Uli Posts: 190
    Standard right hand thread (at least the last I was dealing with). Maybe crank removal tool and some sort of washer could help you.
  • supersonic
    supersonic Posts: 82,708
    M8.
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  • The Rookie
    The Rookie Posts: 27,812
    That's what I thought SS but a stnd M8 bolt won't go into the end of either my spare square or the one I want to remove, unless its a friction thread?

    Uli, thanks, but have a think and realise that's not happening!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    new bolt, £6

    http://www.chainreactioncycles.com/Mode ... elID=34652

    comes with free bottom bracket...
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  • The Rookie
    The Rookie Posts: 27,812
    Did you even read the frickin post FGS? 4r5e!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • nicklouse
    nicklouse Posts: 50,675
    The Beginner wrote:
    What thread is the standard crank retaining bolt, trying to help a friend remove the BB and the previous owner has mullered the spline pattern somewhat so I want to buy a bolt to lock the BB tool in place.
    splines?

    what are you actually trying to do?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • Uli
    Uli Posts: 190
    Uli, thanks, but have a think and realise that's not happening!
    Try asking again so people actually know what is happening...
  • benpinnick
    benpinnick Posts: 4,148
    Zipties round the tool can be surprisingly effective.
    A Flock of Birds
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  • njee20
    njee20 Posts: 9,613
    Try asking again so people actually know what is happening...

    +1

    Splines? Tool slipping? Lost me.
  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    The Beginner wrote:
    Did you even read the frickin post FGS? 4r5e!

    Ok, clearly a sense of humour fail, so I'm out.
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  • nicklouse
    nicklouse Posts: 50,675
    Ahhh right got it now. a bolt and washer to go through the BB tool to hold it against the BB cup to get extra perchace.

    M8 is the standard but many dont use that standard but use others rincluding M12 and M14 and maybe a few others.

    What are the cranks and fitting?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    Thanks Nick for reading my post.

    Uli I'm removing the BB not a crank, mr finger, how would a crank bolt help me remove the BB which it clearly states I want to do by bolting the tool in place?

    If I try an M8 it binds up after 2 turns, it's a square taper but no ID as the rest is buried inside the Giant frame. Cranks are Shimano SIS one piece of indeterminate age (don't have ID as they were binned as we are fitting new ones), but guess at mid to late 90's.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • stubs
    stubs Posts: 5,001
    Might just be full of rust and crap. Try running an M8 tap in if you can get your hands on one. Sometimes its easier with damaged splines to clamp the BB tool in a vice and use the frame as a spanner you can get someone to press down on the other end of axle while you wiggle the frame backwards and forwards to break the seal on the threads.
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  • The Rookie
    The Rookie Posts: 27,812
    Stubs, good call on a vice......

    I'll try the bolt again, have a spare arm to hold the axle with.....
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    The Beginner wrote:
    how would a crank bolt help me remove the BB which it clearly states I want to do by bolting the tool in place?

    You didn't say you already had any bolts. You just said you wanted a bolt that fitted, to lock the tool in place. I have no idea how long a bolt you want. You've already said it isn't M8 thread. A crank bolt would definitely fit.

    Personally I'd just use an impact driver, seeing as you're trashing the BB anyway.
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  • The Rookie
    The Rookie Posts: 27,812
    Crank bolts would be far too short.....a stock BB tool being well over an inch long, as the splines are mullered already, one slip with an impact driver would be curtains, so I'll pass on that ta.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • nicklouse
    nicklouse Posts: 50,675
    you have checked the threads of the crank bolt against the new bolt?

    if they are the same then the threads in the BB are in need of TLC or a bit of brut force.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • nicklouse
    nicklouse Posts: 50,675
    The Beginner wrote:
    Thanks Nick for reading my post.
    I did have to re read it a few times to finally get it.

    your topic heading puts the mind in the wrong direction.

    Buggered BB splines would have worked better.

    is the axel hollow? would not have thought so.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • stubs
    stubs Posts: 5,001
    nicklouse wrote:
    a bit of brut force.

    Wouldnt plus gas or WD40 work better than aftershave
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • The Rookie
    The Rookie Posts: 27,812
    Axle isn't hollow unfortunately.....

    The plastic support at the other end has been trashed, easy enough to remove once the rest is out but I've drilled a small hole and pumped some penetrating oil inside.

    I can't get much brute force on it as the tool rides out the damaged spline.

    Just figured the issue, my M8 bolt is a different thread pitch, I think the crank bolts are fine pitch.....will get the pitch guages out in a bit, thanks for the helps....just need the right bolt now!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • nicklouse
    nicklouse Posts: 50,675
    just hold them together and see if they mesh. if not then measure.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    LOL, did that, they don't, not had a chance to measure yet!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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