Two years ago Nike approached Kirsten Schambra to create the next iteration of their foldable walking shoe. Nike’s first such effort—the Pocket Knife (above), a packable climbing shoe—was released in 1998. That shoe in turn inspired City Knife (right), a foldable shoe introduced last year. Now comes City Knife II, a lightweight shoe that can literally be stashed in your back pocket.
Schambra looked at ways to make City Knife II lighter and more packable. Her initial ideas were inspired by origami, in which paper is bisected, folded, and tucked. She sketched some quick ideas and then began experimenting with them. One concept involved slicing a piece of synthetic leather so that you could simply slip your foot into it. A second idea added creases to the form that, when unfolded, create structure.
To create City Knife II, Schambra drew on her previous work at Nike in developing new ways to streamline sports shoes. She designed the Avow, an athletic shoe for teenage girls with safety in mind (there’s room on the heel to write your name, phone number, and medical information), and created a training shoe for American sprinter John Drummond.
Next Schambra taped an outline of her rough concept to a shoe last and—using Whiteout and black and blue markers—began sketching the design. To provide strength she added a synthetic outsole with screened triangulated pods. Then Schambra marked the shoe with different colors to express function (blue triangles, for example, defined the outsole). Although the piece looks architectural, AUTO-CAD software was only used to draw the molds for the outside. “We’ve tried using 3-D software in designing footwear, but when you’re looking at a foot form, there’s nothing symmetrical about it,” says Schambra, who attended North Carolina State on a swimming scholarship and studied industrial design. “It’s easier to do things in a more traditional way.”
A traditional shoe is made of four pieces: an upper, an outsole, a midsole, and a sock liner. In a first for Nike, Schambra combined the upper with the outsole and joined the midsole with the sock liner as a way of minimizing weight. The shoe’s upper is made of leather with a lightweight stretch synthetic base that allows the foot to expand and contract; the triangle-shaped pods provide rigidity, creating a kind of exoskeleton. The City Knife II is available in unisex style as a low and midheight shoe.
The shoe is available with a black upper and chili red sole. “When a new technology is brought out with a new shoe, we have a tendency to wrap it in a more conservative aesthetic,” marketing manager Nate Tobecksen explains. “Then once it gets attraction, we’ll add more colors.”