Bottom bracket compatibility 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 &quot;gone&quot; 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.
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.