Help needed to identify a bottom bracket

Ramanujan Posts: 352
edited March 2011 in MTB workshop & tech
I've come across this MTB frame with a bottom bracket that keeps coming undone.
Can someone help me identify the BB in question and tell me if there are any tools that can be used to tighten it up? I've never come across a BB like this before.



  • warpcow
    warpcow Posts: 1,448
    That's not the BB, it's just a part of the GT I-drive suspension. The BB will be a standard square-taper or Octalink, by the looks of it. Remove the Crank arms and you'll see.

    Is it the BB itself, or the arms that are coming loose, and what do you mean by loose (play in the axle or something else)?

    Edit: or is their play in the actual BB-shell?
  • Ramanujan
    Ramanujan Posts: 352
    Ive had a closer look and your right: there's a square taper BB housed inside that big silver round thing (GT I-drive suspension, you say).

    It's the big silver round thing that keeps coming undone. It seems to be unscrewing from the frame. Is there a specialist tool you can buy to tighten it?

    thanks for your help.
    I think I'll ask on the MTB forum. I should have done that to begin with.
  • Matt 24k
    Matt 24k Posts: 186
    First go to and search through the various years of GT on there. It's hard to from your pic but looks like some sort of GT DH i. Once you've worked out what model and year you have go to and download a manual from the historical technical section. If available the manual will show you how to adjust the bottom bracket holder.
  • Ramanujan
    Ramanujan Posts: 352
    thanks Matt...that's really helpful