inturnal & exturnal bottom brackets

john lynch
john lynch Posts: 81
edited May 2011 in MTB workshop & tech
can an inturnal bb be changed to an exturnal bb????
if so how?
lapierre zesty 714

Comments

  • nicklouse
    nicklouse Posts: 50,675
    it depends on which you are talking about.

    but most just fit. nothing to do. except make sure the BB shell has been faced.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • warpcow
    warpcow Posts: 1,448
    It depends especially on whether you're referring to a Zesty (like in your signature).
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  • john lynch
    john lynch Posts: 81
    yes it is for the zesty,xt bb want to fit the new xtr race cranset and it rubbing the frame.
    lapierre zesty 714
  • nicklouse
    nicklouse Posts: 50,675
    same bearings for the XT and the XTR. sounds like you have not fitted something correctly.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • john lynch
    john lynch Posts: 81
    would it make any diffferance as im going from a 3 ring to a 2ring???
    lapierre zesty 714
  • cooldad
    cooldad Posts: 32,599
    It shouldn't, have you fitted the spacers correctly?
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • john lynch
    john lynch Posts: 81
    there is no spacers on an inturnal bb
    is there?
    lapierre zesty 714
  • Neily03
    Neily03 Posts: 295
    Internal FFS!
    Transition Covert.
  • cooldad
    cooldad Posts: 32,599
    I thought you said going to external?
    In that case whole different ball game - same axle length?

    Isn't a Zesty external anyway?
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • john lynch
    john lynch Posts: 81
    hi no its inturnel but once fitted it rubs the chainstay slightly
    lapierre zesty 714
  • cooldad
    cooldad Posts: 32,599
    Wrong axle length.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • john lynch
    john lynch Posts: 81
    hi, you are quite right the axel is shorter on the the xtr double
    thank you very much.
    lapierre zesty 714
  • john lynch
    john lynch Posts: 81
    hi cooldad,do all the triples have the same length axel in 10speed shimano,sram etc?
    lapierre zesty 714
  • nicklouse
    nicklouse Posts: 50,675
    ok then what have you bought?

    XT and XTR use all the same widths and are fully interchangeable

    so lets have some part numbers.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • john lynch
    john lynch Posts: 81
    hi,part to take off
    shimano xt
    fc-m770/771-k 3ring 10 speed

    new part
    shimano xtr race 10 speed 2 ring
    fc-m985
    1lsikr191i22
    or chain reaction part id b29td4a

    the xtr is 3 quarters of an inch to short
    lapierre zesty 714
  • john lynch
    john lynch Posts: 81
    sorry 1 quarter inch to short
    lapierre zesty 714
  • nicklouse
    nicklouse Posts: 50,675
    john lynch wrote:
    hi,part to take off
    shimano xt
    fc-m770/771-k 3ring 10 speed

    err the 770/771 are 9 spd.

    and very different which was it?

    but it should be a straight swap.

    which 2 ring version of the XTR is it? (ring sizes)

    also what is rubbing?

    what year is the bike?

    and if it is the small ring then it may just be incompatible with your frame.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • john lynch
    john lynch Posts: 81
    all parts are 2011 so is the bike
    the xtr ring sizes 30/44
    its one of the knobs on the side of the tooth rubbing the frame digging in slighty
    about a mm
    lapierre zesty 714
  • njee20
    njee20 Posts: 9,613
    It's either 30/42, or 32/44, if the chain ring is rubbing it just sounds like it's not compatible with your frame. Need to change for smaller rings.
  • john lynch
    john lynch Posts: 81
    its def 30/44
    lapierre zesty 714
  • nicklouse
    nicklouse Posts: 50,675
    i would have a chat on the Welovelappire forum (or some similar name) about compatibility. as you could go to a 28 small ring but that may still cause issues.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • john lynch
    john lynch Posts: 81
    i think i will send it back and wait for shimano introduce a 10speed 44 replacement outer ring for the xt.
    lapierre zesty 714
  • njee20
    njee20 Posts: 9,613
    So it is, apologies, I thought they only did 30/42 or 32/44.

    Do you really need the 44t? Without wanting to get into a separate discussion about ratios, I personally think the 28/40 is a much more usable combination, and may solve your problems!
  • john lynch
    john lynch Posts: 81
    it is what i want well not realy i would love a 46 but thats not going to happen the mount for the front mech is not on the down tube,the only thing i can do is reverse the spacer on the mech and that will only take a 44 max
    lapierre zesty 714
  • njee20
    njee20 Posts: 9,613
    Are you from the mid 90s? Unless you're riding permenaently on the road (in which case buy a road bike!) what possible use is a 46!
  • john lynch
    john lynch Posts: 81
    my choice
    lapierre zesty 714
  • njee20
    njee20 Posts: 9,613
    Try smaller, you may like it.

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