I'm pretty skeptical about "effortlessly 25 km/h with the folding bike, without much pedaling". Other small-wheel folding bikes I've tried (of, I'm sure, much inferior quality) were not so efficient. Awesome if true.
Due to the moving saddle you use more muscle groups and because of the seating position there is much more pressure on the pedals. You use your weight much more with this bike than an ordinary bike where all the weight on the saddle.
they do have gears that help with that, I think. Can be seen in the promo videos from the side. Also, the riders are peddling very slow for the speed they are going.
