I picked up a Yuba Mundo with a stuck seat post for a good price last weekend. I plan to convert it to a mid drive ebike. I set up a Yuba Kombi ebike for my wife a couple of years ago and now I want one for myself.

I am trying to remove the bottom bracket so I can put some drain cleaner in the seat tube and it is not budging. I got to looking at it and now I am curious if someone stuck the bottom bracket in backwards. I have never seen a cartridge bottom bracket that did not have a lip on the drive side. All of the ones I currently have in use have a lip in the drive side and it varies for the non-drive side.

You can see what I mean in the pictures if my words aren’t doing it for you. What do you think? Should I try to remove them as if the cups are reversed?

(note-the mid drive I will be installing does not use the bottom bracket shell threads so if they are damaged, it won’t matter as long as the shell is tact).


Non drive side with the lip

Drive side with no lip.

Are the tines stripped? Are they metal? Might try some kroil and let it sit for a bit.

Based on your plan, just getting it out seems to be the plan. I assume they were installed based on the threads unfortunately. Which means the reverse of BSA threads. You’ll have to loosen the DS to the left and the NDS to the right I think.

Thats crazy that the resistance wouldn’t have convinced the installer to stop.

I put some WD40 penetrant in the cups and they are currently sitting. I have to head into town to get drain cleaner later and if it is still stuck, I will pick up some bolts so I can bolt the bb remover on. I am afraid I am going to strip all the teeth if I don’t.

I have run into the fixed cup NDS, once. Threading was correct on the bike and cups.

I'm pretty sure I have a NDS fixed cup on one of my bikes as well. I'll have to go out to the barn later to verify.

Some cheaper Shimano bottom brackets are “fixed” on the left side. Threading is still English standard: right side-left thread, left side-right thread.

Yes, as mentioned above, Shimano and some other brands had this style.

Shimano pictured below.

I wouldn't use drain cleaner for that. Kroil is way better than WD-40.

Never mind on the drain cleaner comment. I re-read your post and see you're wanting to use the drain cleaner on the seat post.
I would try Kroil though. And definitely clamp your bottom bracket tool so it can't slip.

The right side is reverse thread. Left is standard thread. If you are turning in the right direction, use a long bolt to retain the BB tool and a pipe over your crescent wrench.

You can also inject whatever into the seat tube via the waterbottle bolt holes.

Interesting...odd birds..

Absolutely try what Kontact says first.

...my post above was if someone forced the cross thread in. in which case given BSA thread would be reverse wouldn’t it?

???

Because:

Just for the record, the bb set I had was cup and cones with a driveside lock ring.

there must be a writer communication error.

maybe he meant seat tube waterbottle holes if there? Downtube waterbottle boss holes?

chainring bolt holes are isolated to the crank.

FWIW, I once disassembled a Shimano BB with the lip on the non drive side and Italian thread. '90s Acera - X I think.

Just saw my error - thanks. Yes - seattube bottle bolt holes to get penetrant to the seatpost.

Back to the OP - there is almost no possibility that the cups are backwards, or that they are Italian thread. Use a long lever and turn them in the proper direction.

I stripped the ridges on the non drive side cup. So, I went over to the drive side and it came loose in the standard direction. Now I assume that the non drive side is reverse threaded and that is why I stripped the ridges.

The threads on the bottom bracket shell are fine. All I can figure is that the shell was threaded before it was welded and the person building it on wrong.

Just to be clear - your drive side cup came out by turning it counter clockwise?

What kind of frame is this? Does the lip of the NDS cup have any markings on it?

To be clear, the drive side cup came out counterclockwise. The opposite of any bottom bracket I have ever installed or removed. have never seen anything like it.

And, the non drive side was reverse threaded.

It is a Yuba Mundo from about 2012 or 2013.

That's how Italian BBs come out on that side. So what kind of frame is it?

So you got out the NDS cup as well? Do the threads in the frame match the cups? Does the BB itself have markings on the body? The writing should be oriented so you can read it looking down from the saddle.

Never underestimate the power of the ham fist.

I have a ratty PX-10 that had BSA BB cups and pedals forced into the original crank.

The pedals took pulling the arms and stripping pedals down to the spindle and then in the vise with flats clamped on and a breaker bar to get them out.

Got the cups out with my normal never fail clamping method, scribed and chased the threads and reassembled, torqued and tested with good correct cups and all good now.

Campy French thread pedals ready and waiting.