How tight should a BB be???

bmxboy10
bmxboy10 Posts: 1,958
edited November 2013 in Workshop
Hi I have tried to change the Hollowtech BB on my carbon road bike. I have all the correct tools and with the cranks off and the spline tool fitted to the cups neither cup will budge. I have plenty of leverage using a 16-18" torque wrench. I have applied some WD40 to the cups but they are tight as ar&^%$£es! I am a bit worried and don't want to get the hammer out being that its a CF frame:)

Do you think this is correct? All the Youtube vids show the cups coming off quite easily.

Comments

  • nicklouse
    nicklouse Posts: 50,675
    first are you turning the tool the correct way. read park tools.

    yes videos make things look easy as they have undone every thing first. they are only there to show the principal not how to do it.

    Parktools alo list the torque settings for tightening which will give you an idea of what force is needed.

    WD40 is a very very poor release agent and really has very little use on a bike.

    how are you clamping/supporting the frame while working on it? as poorly held/supported will cause more damage than a tight BB cup.

    torque wrenches should not be used to undo things as you can damage them. get a breaker bar ( which is why they are called that).
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • lackofgrip
    lackofgrip Posts: 851
    Make sure the bottom bracket is supported on a good quality work stand. Bottom brackets undo forwards on both sides of bike. Get a breaker bar. If they've been in a while they'll be tight yes sir!
  • keef66
    keef66 Posts: 13,123
    For BB work I have the bike held upright but standing on the garage floor. That way I can apply the neccessary amount of grunt without the bike wobbling all over the place in the workstand. Sometimes a very long breaker bar is required to shift a stubborn BB. Nicklouse in the past has posted some excellent pics of such a device in use professionally removing a very rusty BB

    As above, standard English threaded BB unscrews forwards both sides, ie clockwise on the drive side and anticlockwise on the non drive side
  • frisbee
    frisbee Posts: 691
    Mine were pretty tight, some water had made its way into the frame. I managed to get them off with an all in one tool but it took effort.
  • johnmiosh
    johnmiosh Posts: 211
    Sometimes difficult to get enough leverage to remove. You can use Stillsons/pipe wrenches

    http://uk.farnell.com/jsp/displayProduc ... tAodFVUAtw

    But it will chew up anything it is used on including the bottom bracket shell if you are not careful.

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