The o.p. is looking for a trike, not a bike, and I have to admit the DiBlasi folding trike is darn slick. Check it out: . But that kind of slick comes with trade-off's, weight being only one of them. What is 21.7kg in pounds anyway? Bet you lunch that weight doesn't include vital equipment like tires, reflectors, handlebars or pedals...

In 2016 upright style configured trikes are mostly relegated to the senior and disabled sector of cyclists. They have their devotees in the United Kingdom, but most everywhere else they do not scream value or performance. Any delta trike will have a much lower center of gravity and resulting stability in turns than any upright adult tricycle. At least a couple of them fold.