This is not easy, I`we been trying for a long time to find a stem for a folder with a 1" quill type bottom. Not easy. You need to know what online shops to visit. On the pages of the bike dealers (like Dahoon) they show the product and tell you what bikes it will fit- and maybe not fit on. But often they do not tell you what you need if you are shopping for a different bike, so unless you`we got the bike or can ask somebody you are lost.

Same with BB. If you are shopping for something "not normal" like a BB for an unusual size (something between normal and BMX) there is no way to find out. Guess it is a lot of work to keep the online shops updated, but still..