Strictly technically speaking, a folding exercise bike is a variation of either a recumbent, upright or indoor cycling bike, with the added functionality of a folding frame. This way, those who are living in small houses or apartments are still able to get a good, quality workout, without having to turn their living room or bedroom into a makeshift gym. Once you are done exercising, you can simply fold the bike, and tuck it away neatly for later.
Check out some of the reviews I have provided you with and find out if a folding bike is what you have been looking for all along.