The Strida 5.0 – an Urban 2.0 mode of transportation is probably most portable of wheels for city get about. It weighs 10 kilograms and has a collapsible triangular frame. The Strida is long and narrow, and carries like a photographer’s tripod (I can fold it while running down the platform at Grand Central). An easy way to visualize it is to picture three tubes in a triangle. Two points are hinged, and the third is a latch. When unlatched, the tubes fall together to look like a group of parallel tubes with a seat and wheels. Assembly is just forming the triangle, then click and go. This design is very clever, yet simple and robust. Greaseless, very compact and guaranteed maintenance free. From $985. For dealers, see www.strida.com.