Hello, I am trying to restore my (very old) trekking bike – the BB removal was done by a bike shop and involved heating up the frame to remove it, it was kinda rusted in place.
After, I had the frame powder coated in a lovely shade of green, but it seems some deposits from that process settled in the BB threads. Also, the deeper threads are not in great shape, but hope the thread on the outside is enough for it to be functional.
Now, the deposits seems kinda soft, I can scratch them off carefully with a metal awl, but that is kinda tedious, and I'm a bit worried of scratching the softer metal of the frame.
What would be the best way to clean these up? Do I need to ask my LBS for cutting the threads, or should I try with a brass/steel brush (like the small tooth-brush sized things?), or shall I just try to install a BB with some grease and see what happens…?
Any advice is welcome!
by Dr_JA
8 Comments
[https://www.parktool.com/en-int/blog/repair-help/bottom-bracket-tapping-threading-chasing-and-facing?srsltid=AfmBOoo9WhU_O3znkuAeDGZ3Bsiow584VSFM-Z4uGgIOhXEzjzF1wcHo](https://www.parktool.com/en-int/blog/repair-help/bottom-bracket-tapping-threading-chasing-and-facing?srsltid=AfmBOoo9WhU_O3znkuAeDGZ3Bsiow584VSFM-Z4uGgIOhXEzjzF1wcHo)
[https://www.parktool.com/en-int/product/bottom-bracket-tapping-facing-set-bts-1](https://www.parktool.com/en-int/product/bottom-bracket-tapping-facing-set-bts-1)
If it were me, I’d clean with a wire brush, then grease and try an install.
If you’re cautious, having your LBS chase the threads can’t hurt your wallet too much.
Or if you’re nuts, slice and dice an old BB and tap your own threads (it can be done but don’t).
You should just take it to a shop and get it chased and faced. It’s the best deal at most bike shops, as it uses the most expensive tools.
Old steel bottom brackets might be happy to thread in, and slightly reform the shell threads, but now many BBs are aluminum or plastic, and will get messsssed up, and potentially stuck.
I have no doubt those will be fine after getting sorted at a reputable shop. Good luck!
This looks worse than simple oxidation and dirt. I’d retap with a bike shop.
Definitely go to the right bike shop and tap those threads. What’s amusing is how new bikes and frames are different from the ancient era so not every mechanic is experienced with cutting threads.
In the ancient days, many bikes came as framesets which required bottom brackets to be installed. Some frames arrived poorly faced so a mechanic had to face threads on new bikes regularly.
Today, frameset are typically from higher quality builders and they will face the threads. And with assembled bikes, engineering typically ensures higher quality threads.
I don’t think every shop faces threads regularly. This is where the old school shop is best.
[removed]
cant chase whats not there
You could install a sealed bottom bracket that doesn’t use the threads in the frame. I’ve used the YST threadless sealed BB on several frames with damaged BB shells with great success.