What can anyone tell me about this...the frame adapter making a boys bike in particular. I took a look around but have only found adapter for transport that make it easier to strap to a rack.
Search using the term 'convertible' and you should find more info concerning bikes like yours.
For example, did a google images search for 'Columbia convertible bicycle' (without bicycle you just get a lot of pants ) and this was among the first three rows of images...
Do you realize that is a 20 inch bike?
If you are thinking for a 26 inch maybe check out @theRenaissance Man and his tanks. Awesome product and RatRodBikes member!
I decided to pass on taking this frame, and the other that was a package deal. Looked interesting ...both bikes were 20in. The other was an old Columbia apache....so far gone though....only thing without big scaly rust were the decals.