Removing a stuck Mavic 610 unthreaded bottom bracket...any ideas?

[sjcprojects]

The BB is now removed. Once just the shell was left in there, I tried hitting it a few times with a mallet which did move it a little, however it soon started deforming the fairly thin metal so I had to stop that approach before it all folded into itself. I then tried pulling it with some vice grips, but not too surprisingly that did nothing, apart from take a piece out of the shell:



I then moved onto sawing through the shell. After sawing one cut, and then trying with the mallet again, nothing was really improving. I thought I'd have to saw another cut to have any chance of it coming out, which was more than I really wanted to do at this point, so the blowtorch option was looking most likely. I had my neighbour primed to use his on it, but then I had one last idea.

I tried a large flathead screwdriver against the lip of the thicker inner part of the shell which the bearings sit up against (as can be seen in the image above), and hit it with a hammer. This actually caused the shell to move a fair bit, and after a decent number of hits it was finally out:



I don't know if having made the saw cut made any difference, but just the vibrating movement caused by this might have had an effect, I guess.

The best news is that thanks to @mdvineng I can actually reuse the BB with a replacement shell (or sleeve, or whatever it should be called), which I thought would be an impossibility. Retrobike comes good again...

 

[bikeworkshop]

Great result!
Cut definitely helped.
Looks like the corrosion was limited to exposed areas only.

That looked Desperate!

 

[roronoa]

I have a frame with a very stuck Mavic 610 BB, which is an unthreaded BB - the only threaded parts are the outer ends which stick outside the BB shell which the lockrings thread onto. Once the lockrings are off, it should be loose in the frame and just come out. Unsurprisingly given the state of the frame, instead the BB seems to have bonded itself rather nicely inside the BB shell.

I've put some penetrating oil (WD40 brand) down the seat tube, and given it a whack with a mallet from both sides, but no movement at all so far. I suppose I could try putting one of the threaded ends into a vice and try turning the frame to get some rotational force on it - which would almost certainly damage the threads (though saving the BB is unlikely anyway, I guess) - but I'm very doubtful it would give enough purchase to do that.

The problem is that there's no way of getting any sort of tool onto anything. I guess I'll have to resort to getting my local frame repair guy to heating it up to get it out, but I just wondered if anyone might have any other ideas...is it worth trying Plusgas or similar?

Good evening, excuse me for butting in, what brand is your bike frame? I have a track bike frame with the same pattern on the bottom.

 

[sjcprojects]

Good evening, excuse me for butting in, what brand is your bike frame? I have a track bike frame with the same pattern on the bottom.

No problem at all. It’s a Condor frame. I don’t know if those cut outs were particularly a Condor thing (or a Dave Yates thing - he made this frame). I suspect they are just a fairly common pattern on some BB shells.

Condors tend to have the name stamped onto the frame somewhere, so if yours doesn’t, it probably isn’t one.