1

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.

  • 1
    Have a LBS re-tap those threads, I bet there's enough for a new cartridge BB to work just fine – whatsisname Jun 19 at 6:06
  • @whatsisname that sounds like, dare I say it, an answer – Weiwen Ng Jun 20 at 16:20
0

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.

| improve this answer | |
  • 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 Jun 18 at 11:21
  • You believe that the new BB will be able to "make" a new thread on the drive side? – Barry O'Connor Jun 18 at 11:31
  • 2
    If you have the BB faced, have it tapped at the same time. Better than steel brushes. – Vladimir F Jun 18 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 Jun 18 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 Jun 18 at 14:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.