Common Upper Materials
Cordura: The Cordura fabric brand name encompasses a wide range of typically nylon fabrics known for their high tensile strength fibers. Cordura fabrics are generally water repellant, abrasion resistant, and come in a variety of weights / weaves. Running shoes sometimes make use of this material in uppers, for better durability and protection relative to the often softer, stretchier knit fabrics.
Matryx: A performance textile used in higher-end trail running models from a few brands. Matryx fabric is made from woven polyester threads that are individually coated with protective coatings. It’s known to be incredibly resistant to abrasions, flexible, light, and quite breathable (especially relative to traditional burly fabrics like Cordura). Performance-oriented trail shoes will incorporate Matryx by weaving it directly into their uppers or using it as a lightweight alternative to TPU for protective / supportive overlays.
Dyneema: Technically, Dyneema is an ultra-high-molecular-weight polyethylene. Dyneema (also known as ‘Cuben Fiber’ or ‘UHMWPE’) is known to be incredibly strong, abrasion resistant, and lightweight, and can be utilized in the form of fibers, yarns, woven fabric, and non-woven, laminated fabrics. It’s not yet widely used in trail running shoes, but as the technology and production cost become more affordable, expect it to be featured as part of new upper materials. Some brands that are currently taking advantage of Dyneema (e.g., Speedland) utilize the material in upper fabrics or even as a thread to reinforce the midsole-upper connection, due to its high level of durability.
Gore-Tex: A waterproof Teflon membrane used in some waterproof versions of trail running shoes (and a whole bunch of other products). Gore-Tex materials block liquids and air while allowing some vapor from sweat to pass through, but a shoe with a waterproof laminate will neither drain as well nor breathe as well as an equivalent shoe without one.
While many brands opt to use a name-brand Gore-Tex insert for their waterproof shoes, many others use different membranes, but the idea is similar. Weatherized versions of trail shoes also tend to keep feet warmer in cold conditions than shoes without a waterproof lining, so models outfitted with Gore-Tex and the like can be a popular choice for winter running.
‘Engineered Knit’ Fabric: While the vast majority of shoes’ uppers consist of some sort of knit fabric, recently, more complex knitting processes have allowed shoe designers to incorporate several different functions into a single piece of material, which can allow them to more precisely decrease stress points, reduce weight, increase durability, and maximize breathability. Some “engineered knit” uppers also don’t need to be trimmed, resulting in less waste during production. Constructing uppers from a single piece of fabric also eliminates seams, adding comfort by decreasing the amount of internal stitching needed in the shoe.
Kevlar: A synthetic, strong, heat-resistant fiber that can be woven into flexible sheets and used in overlays and uppers. Kevlar’s strength-to-weight ratio is nearly 5 times stronger than steel, which makes it a great option for reinforcing higher-end trail shoes designed for rugged terrain.
Aramid Fiber: This is actually the same exact thing as Kevlar; Kevlar is just the trademarked brand name of this light, strong, heat-resistant fiber.