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Bottom Bracket Compatability

GussioGussio Posts: 2,452
edited October 2011 in The workshop
Need to replace external BB on the MTB. Currently Shimano XT. Have an unused Ultegra BB lying around - would this work with an XT chainset if I swap over the spacers from the old BB? Both Hollowtech. Or is it a visit to the LBS for a new XT BB?

Posts

  • Should be fine in theory I think. Check the axle fits properly before you screw the cups in.

    If you decide not to use the Ultegra I'll take it off your hands as the BB on my commuter is on the way out.
    <a>road</a>
  • GussioGussio Posts: 2,452
    Should be fine in theory I think. Check the axle fits properly before you screw the cups in.

    If you decide not to use the Ultegra I'll take it off your hands as the BB on my commuter is on the way out.

    Roger that. Will be in touch....
  • Alternatively if the fit is a little snug, just whack it with a hammer til it slides home.

    Let me know if you want to borrow a hammer.
    <a>road</a>
  • GussioGussio Posts: 2,452
    ;)
  • mister pmister p Posts: 405
    Road Hollowtech II bottom brackets are slightly wider cups than MTB ones. So you can use it but check how much the non-driveside arm is on the crank axle. You may need to remove a spacer or use slightly thinner ones to get it to fit and maintain the correct chainline.
  • nicklousenicklouse Posts: 81,520 Lives Here
    thez are similar but not the same.

    the threads on the drive side are shorter on the road bike so if zou have 2 spacers zou may be short of thread in the frame. also the cups are not quite as wide. which again can cause issues.

    but often things work fine as it does depend on the whole package just be aware of the issues above and it should be fine.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • phy2sll2phy2sll2 Posts: 680
    nicklouse wrote:
    the threads on the drive side are shorter on the road bike so if zou have 2 spacers zou may be short of thread in the frame..

    :lol: German keyboard?
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