A portable electric bike folds to backpack size when not in use, allowing riders to use public transportation with no problems

Neither folding bikes nor electrical bikes are anything new, but the “Impossible” electric bike brings something unique to the table by offering both. The bike weighs 11 pounds and folds up to 17-inches tall — small enough to fit in most backpacks and light enough to carry easily.

Key to the design is its brushless electric motor. A brushed motor works by spinning the turbine between poles of a magnet. This means swapping the polarity (which is positive and which is negative) by means of a moving brush, which requires more weight, size and moving parts. A brushless motor puts the magnet on the rotor itself and rotates it by charging electromagnets on the outside. The charging is managed by microcomputer. Brushless motors can be smaller and have fewer moving parts than a brushed motor — making them just the thing for portable electric devices.

More: http://www.psfk.com/2014/11/impossible-by-impossible-bike-brushless.html