Bottom Bracket

Can anyone help me identifying the bottom bracket? It had a cottered crank arm but only on one side, the other side has nothing.

I have no idea how to remove the spindle. I already tried hammering it out but it doesn't really move. I found nothing on the internet so far featuring this bottom bracket.

  • Hi, welcome to bicycles. To be clear you aren't interested as much in actually identifying the make as you are in figuring out how to disassemble and maintain it, is that correct?
    – DavidW
    Commented Sep 14, 2021 at 16:08
  • 1
    You unscrew the nut that's holding the spindle against the bearings. Note that with this vintage one side is usually threaded "backwards" (righty-loosy instead of righty-tighty). Commented Sep 14, 2021 at 16:17
  • Hi, David! THanks for the welcome! Yeah exactly if there wouldn't have been a solution for dissambling, i would have searched elsewhere if the type was known.
    – l_riegler
    Commented Sep 14, 2021 at 16:23
  • Thanks daniel, then i just need to find a tongue to unscrew the nut, since there is only little space to get hold of the nut.
    – l_riegler
    Commented Sep 14, 2021 at 16:24

1 Answer 1


enter image description here
The part with the red arrow needs to be turned - as Daniel R Hicks has said

righty-loosy instead of righty-tighty

Your bottom bracket appears to be a variation on the Thompson bottom bracket.

The Thompson bottom bracket uses adjustable spindle cones and cups pressed into the bottom bracket shell like the Ashtabula bottom bracket. Unlike the Ashtabula crank, the non-drive side crank is removable, allowing for a smaller bottom bracket shell. Frames with either Italian or English bottom bracket shell diameters (independent of threading) may be fitted with Thompson bottom brackets.

Here's a picture to give you some idea of what it looks like apart.
enter image description here

Here is a video of working on something similar.

  • Yeah, it worked perfectly. anaged to get a grip on the nut and loosen it. Thank you very much for your input!!
    – l_riegler
    Commented Sep 15, 2021 at 19:42

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