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Did I cross thread my bottom bracket?

maxrodgersmaxrodgers Posts: 19
edited August 2014 in Workshop
Hello all,

I am in the middle of upgrading a vintage steel bike. The other day I replaced the old bottom bracket with a shimano UN55 sealed cartridge BB. I haven't been able to get the fear out of my head that I may have cross threaded it. I am aware that the non drive side is normal threaded and the drive side is reverse threaded so that is not the problem.

I started screwing the bottom bracket into the shell by hand on the non drive side and it took a while for the threads to catch one another. The first couple of turns were easy and then it stiffened up. It wasn't really stiff but my hands were a little greasy and I could no longer turn it by hand. So at this point I had to switch to using the BB tool and a crescent wrench. It turned smoothly all the way in using these tools but certainly gave resistance. Again, not loads of resistance, I wasn't straining to turn it but I definately could not have done it by hand. Does this sound like I have cross threaded it? Everything was well greased and I had cleaned the inner shell before installation.



  • carefulcareful Posts: 720
    If it went all the way in,with no strands of thead flaking out, and looks evenly inserted all around then probably not. Only way to really know is to remove it and inspect the threads. You will probably have to remove it sometime for maintenance. I would do so now as it will only get tighter with the passage of time. If it is ok but still tight, get lbs to run a tap through it. Worst case if it is stripped is to get a helicoil type thread insert put in. Hopefully ok and you will get sound nights sleep.
  • lapavoni10lapavoni10 Posts: 146
    If you got the cup all the way in on a steel frame, without the aid of a 6ft bar, you should be ok.
    I would suggest you remove the cup and clean the frame threads with some wd40 and a toothbrush, then use copper grease to re-install.

    Did you have the frame resprayed? You may want the lbs to run a tap through the frame.
  • Thanks, I will try these suggestions and confirm if they work.
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