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I have a new to me, old to the world Bianchi road bike. When inspecting it and taking it apart the bottom bracket threads are stripped out for 1-2 cm deep. This lead to the sealed cartridge unit not being able to thread and traveling back and forth alot (besides not being able to actually use the bike).

I have not tried anything yet and am just looking for advice as for next steps to be able to use it.

Thanks in advance!

1 Answer 1

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Well, if the threads were chased with a tap, you might get purchase, but it sounds like you're not going to get that here.

If it's a BSC/British thread, you can get the bottom bracket shell tapped to the Italian standard, and use 1mm spacer on each side to get the BB located properly (italian BB has a slightly larger thread diameter and is a 70mm shell instead of BSC 68mm). There was a Sheldon Brown article about this but I can't find it for you.

Otherwise, "threadless" bottom brackets exist for square taper cranks (and some 24mm spindle cranks) that tighten on themselves rather than the threads in the bottom bracket. Thay have their own problems but will be the cheapest/quickest solution for you.

If your frame already has Italian threads and they are totally ruined, you might be out of luck without major surgery. Though there are still ways to repair these things, the processes quickly start to become uneconomic depending on the value of the frame.

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  • "If your frame already has Italian threads" - pretty likely for an old Bianchi Oct 10, 2022 at 23:39
  • @whatsisname What is "old"? Is it 10 or 20 or 30 years old? That's probably not an italian thread on a Bianchi. Is it 40 or 50 years old? Maybe it is.
    – Noise
    Oct 11, 2022 at 9:37
  • I had a Bianchi from the 90s that was Italian threaded. Oct 11, 2022 at 10:57
  • @whatsisname that's nice for you
    – Noise
    Oct 11, 2022 at 15:44
  • Thank you for the advice and help! I really appreciate it, I think I'm going to take the frame to a bike shop to see if they can help me out with the retapping the threads and then moving on to BB solutions after that! Thanks 🙂
    – Bike bill
    Oct 13, 2022 at 1:10

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