Fixing up a GT Ruckus uf? Previous owner had removed the cranks and BB. I attempted to put in a used BB, but there is a ledge inside the BB that won't allow me to put in a normal cartridge BB. The ID of the ledge is smaller than the OD of the BB. The BB is threaded, so it's not a press fit or anything. I tried tapping the "ledge" out, as it looks like it's a piece of metal that's jammed in there, almost like a collar, but it didn't budge.

As of right now I'm stuck with an old cup and cone BB as nothing else would fit. Unfortunately it's also a wide BB, so I need to find a very specific bb spindle to make it work.

Anybody have any advice for what would be wrong. I have no pictures unfortunately.

Dremel?

After image searching the model of GT it appears it is single speed and came with BMX cranks originally, is that the right one? I was going to say check if it has a cable guide underneath the BB shell, I've seen that bolt hold a BB center sleeve in place pretty tightly. But if it's all single speed BMX stuff on a MTB frame it's probably not that. Could still be an old center sleeve though, I have a pile of loose center sleeves from BMX bottom brackets and they vary in wall thickness quite a bit. Wouldn't be too hard to grab the wrong one and get it stuck in there. Is the metal a different color than the threads on the BB shell?

Might also just be the frame/BB shell. I have a bike that will only take specific bottom brackets, it's not raised exactly but has no material removed in the center like you usually find.

This is one more example of words only failing to convey the actual situation. Photo's please. Also any links to an online spec sheet for the bike when new would help. I'm not the only one here who won't bother with searching for more info. Like a restaurant not bothering to cook the food and instead have it served raw hoping the patron will do the final work to cook it. Andy.