(Possibly) unusual bottom bracket shell

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  • I’m doing a bit of work on a friends old roadbike/single speed conversion (frame of unknown origin).

    I just took the cranks off and it seems the drive side race is built into the shell (unless I’m missing something?) Not something I’ve seen or heard of before. I was planning to install a Sturmey single crankset and this puts paid to a sealed cartridge bb. I guess cup and cone only for me.

    The shell is 72mm which seems to be unusual too. The cranks need a 103mm spindle, can anyone recommend the right BB?

    Many thanks


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  • That just looks painted over

  • That could be it - it has the slots for a tool tool which would also be a giveaway right?

  • Painted over. It'll probably be shiftable. But sometimes these are tacked in also.

    Even if you leave it, you can still SS it with the same axle or new one with a different length and loose balls (if the races are still ok). Maintenance is a bit messier (not much though). But I have bikes with loose ball BBs that are older than me and fine.

  • Thanks - Yeah I have no issue with cup and cone but its just for a casual cyclist friend who would be much better off with a fit and forget cartridge...

    I'll try and get it off but there's very little purchase on the slots with the thick (probable powder coat) over the top. Might have to try and scrape some paint away...

  • Actually if i get my headset press involved I might have a chance of getting it loose

  • Hi if the other side is out I would spray from the inside , there a tool that fits on this shell just remember to loosing and not tighten it
    good luck

  • OK you got that?!

  • Got that! I feel there's going to be many more questions with this one!

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(Possibly) unusual bottom bracket shell

Posted by Avatar for redman79 @redman79