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After two LBS's, a blowtorch and a tyre shops impact driver I finally have my bottom bracket out. It an aluminium frame if that makes a difference.

On the drive side some of the thread is gone, although not so much that the socket can freely be pushed in.

Would I need to move to a threadless bb or could I force the drive side in to retread/lock into remaining threads?

Picture of the drive side: https://ibb.co/6WJN24P

Also, this is a 68x127.5 bb. Would a 68x127 work? If I have to go threadless, the yst 127mm is far cheaper and more available. I just don't know if enough thread is "gone" for it to fit in. Also the non drive side is almost fine.

I should add that sending the frame to a specialist retapping shop would simply not be worth it for this bike!

EDIT: The bike is an old Dawes 401 with a rockshox gps fork that has failed but functions as a solid fork now. This bike also requires new cables and perhaps new shifters. I know it would probably be better to just switch to a new bike but I feel it would be a big waste to scrap this.

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    Have a LBS re-tap those threads, I bet there's enough for a new cartridge BB to work just fine
    – whatsisname
    Commented Jun 19, 2020 at 6:06
  • @whatsisname that sounds like, dare I say it, an answer
    – Weiwen Ng
    Commented Jun 20, 2020 at 16:20

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You cannot use a 'threadless' bottom bracket in a threaded shell. Perhaps you are thinking of two-piece bottom brackets designed for press-fit frames that thread together and are designed to eliminate bearing misalignment and creak. These only work because they fit very accurately into the press-fit bearing cups.

The 127[.5] measurement refers to axle length. Each crank model requires a different axle length to get the correct chainline. 0.5mm will not make a difference.

What I'd do is have the BB shell faces faced to give a clean flat surface to the flanges of BB to butt up against, and clean the threads as much as you can will a wire brush and pick. Install the BB with a generous amount of thread locker.

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  • I see. I thought the threadless bb's were specifically for instances where you have stripped your bb. Like this one; sjscycles.co.uk/bottom-brackets/… I think your solution could be the best though!
    – Barry O'Connor
    Commented Jun 18, 2020 at 11:21
  • You believe that the new BB will be able to "make" a new thread on the drive side?
    – Barry O'Connor
    Commented Jun 18, 2020 at 11:31
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    If you have the BB faced, have it tapped at the same time. Better than steel brushes.
    – Vladimir F Героям слава
    Commented Jun 18, 2020 at 11:53
  • @BarryO'Connor No, the BB won't make any new thread. I think there are indeed such threadles BBs for striped BB housings. I would go for those.
    – Vladimir F Героям слава
    Commented Jun 18, 2020 at 11:55
  • I was talking about BB's like these wheelsmfg.com/bottom-brackets/bb86-92/…. The one you linked is obviously for stripped shells, I would have thought you need to ream out the shell to remove all the threads to use one of those
    – Argenti Apparatus
    Commented Jun 18, 2020 at 14:02

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