I've been writing quite a bit lately about ultralight down jackets, tents, and shell jackets. In these ultralight categories, one of the elements that makes a significant difference in weight is the weight of the threads being used to create the fabric.
The weight of a thread is measured according to denier, a spec that is often listed with today's high-tech gear. The smaller the number, the lighter weight the thread. But what exactly is a denier anyways?
A denier is a unit of measure defined as one gram of mass per 9,000 meters of length (there are 28.3 grams per ounce). So if you laid out 9 kilometers of thread, gathered it all up, and weighed it, the denier would be equal to its weight in grams. Denier is commonly abbreviated with a lower-case d: A 50-denier fabric would be listed as 50d.
Gear manufacturers that are trying to cut ounces will often do so by using low-denier fabrics. For outerwear, down jackets, etc., the ultralight standard roughly runs somewhere between 10d - 20d, with a handful of examples in the sub-10d realm. Standard weight outerwear runs more in the 40d - 80d range. Super heavy duty nylon—or "ballistic" nylon, as it's often called—can tip the scales at anywhere from 100d to 600d or more. This is what you find in high-wear places on backpacks, duffel bags, etc.
The trade-off with a low-denier fabric is its durability. It's too thin to take much in the way of abrasion, which is why you often see it in layering pieces that can be protected under a thicker shell, or in ultralight tents, where abrasion is unlikely.
“Equipped” is an AMC Outdoors blog, written by Matt Heid.