Hello, I took two bikes and made them into one.
I cut an old specialized mountain bike just behind the head tube on the toptube and downtube.
I fit this into the rear end of () another mountain bike frame.
To make this permanent I bent the stays in and fastened the stays to the splined bottom bracket with the bolts that usually hold on the crank.
I'm looking for a better way, perhaps an adapter that I can install in the bottom bracket shell, to do this should my current system fail under load. Is there anything out there?