Copyright © Françoise Herrmann
Ever wondered about the suspension cables that criss-cross the uppers of your Nikes? They may appear in various configurations as embroidered threads into the upper’s fabric, as ridges sitting on top, or as strings extending from the lacing apertures that you could almost pluck, sometimes sandwiched between two layers. That’s Nike flywire technology!
Flywire technology with its two sets of crisscrossed strands (41 and 42 on the figure drawing is primarily designed to provide lightweight containment within the void of the shoe, so that your foot does not slip and slide off the sides of the sole or roll forward, especially when the upper is also made of lightweight and form-fitting or stretch material. In patentese, you might say that this is considering "the sole and upper are cooperatively connected."
The crisscrossing and strategic positioning of the strands relative to the anatomy of the foot-in-motion are engineered so that the force load of each thread is known, and the spacing of the threads can be calculated.
In the latest models, the threads are made of Vectran™, a fabricated liquid crystal polymer (LCP) fiber, which has a tensile strength 5 times greater than that of steel and a thickness the size of a human hair! So that when these wires are incorporated into the upper, they provide stronger support that any other sort of materials previously used for maintaining upper support such as leather, polymer sheet layers, textiles or synthetic leather.
There are however significant added benefits to the incorporation of flywire technology into the uppers of hundreds of Nike shoe models, chief among which is a concern for the sustainability of the shoe manufacturing process.
Indeed, according to US20120023778 titled Footwear incorporating angled tensile strand elements, where this technology is disclosed, each material used in the upper of a Nike shoe has a specific function: textiles for breathability, foam compression for comfort, leather for durability, the combination of which adds weight, complexity and waste to the manufacturing process. That is, considering that the various material parts have to be cut, superimposed or connected together to form the upper.
Thus, because of the ease with which flywire technology is incorporated directly into the fabric of the upper, whether woven or knit, it does not add waste or complexity to the manufacturing process. The upper requires a certain amount of thread with no “leftovers”. And whatever is used is usually qualified as “ridiculously light”, which means that athletes have less weight to carry, and thus the added capacity to perform better.
So, if you are looking for green technology… The sort that is surreptitiously part of a planetary effort to cool planet Earth, to reduce waste and emissions of greenhouse gases, then you might consider Nike flywire tech!
The Abstract for US20120023778 titled Footwear incorporating angled tensile strand elements is included below as well as some of the figure drawings.
An article of footwear may include various first strands and second strands. The cutting and second strands may extend from an area proximal to lace-receiving elements to an area proximal to the sole structure. The first strands may have a substantially vertical orientation and the second strands may have a rearwardly-angled orientation. The first strands may be located in a midfoot region of the footwear and the second strands may be located in both the midfoot region and a heel region of the footwear. Angles between the first strands and the second strands may be at least 40 degrees. Additionally, the second strands may have at least fifty percent greater tensile strength than the first strands.