What is this bottom bracket We were doing a volunteer bike repair clinic and came upon this bottom bracket that I've never seen before. It was on a trials bike and the crankset was destroyed but we couldn't find any way to service the bottom bracket and didn't have any matching cranks to replace it with. The bottom bracket was quite large and beefy and like like it would fit a one piece Ashtabula bottom bracket. Didn't end up fixing the cranks as we had no idea how to deal with this.
Looks like this is what's called a "mid bottom bracket". They seem to be common on BMX bikes. They use bearings that press into the frame. I found a video that shows how to remove and install a new one. It seems like the spindle should slide right out from the video but on the bike I was working on it didn't seem like that would have been the case, but I didn't really try to slide it out.