Materials & Fabrics: Complete Guide
Comprehensive technical analysis of sizing, materials, installation requirements, and manufacturer standards for materials & fabrics.
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In plain English
A backpack's fabric is the cloth it is sewn from. Most packs are made of nylon, the same tough, slightly slippery material used in rain jackets and tents. Some use a stronger version of nylon built to resist scuffs. A few very light and expensive packs use a crinkly, plastic-looking material called Dyneema Composite Fabric, which is made more like a sandwich of thin layers than a woven cloth.
You will often see a number followed by the letter D, like 210D. That tells you how thick and heavy each thread is. A bigger number means heavier thread, a bit like how thicker yarn makes a heavier sweater. It does not tell you everything, though. How the threads are woven and what coating is added matter too.
Most pack fabrics are water resistant, not waterproof. A coating on the inside and a water-repelling finish on the outside make rain bead up and roll off. Those finishes wear down with use and sunlight, so a pack that shrugged off rain when new may soak up water after a few seasons.
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Pack fabric — nylon, Cordura or Dyneema Composite — sets the balance of weight, abrasion resistance and waterproofing more than any other single spec on a hiking backpack. Two packs at the same liter capacity and price can differ by a pound or more in weight, or by years in trailhead life, purely because of what the shell is made from. This guide covers what pack fabrics are actually made of, how Dyneema Composite Fabric compares to nylon and Cordura, whether any of these materials keep gear fully dry, and what the denier number on a spec sheet really tells you about durability.
Most hiking backpacks use woven nylon, often reinforced with a ripstop grid and coated with polyurethane (PU) or silicone for water resistance. Higher-end packs substitute Cordura nylon for extra abrasion resistance in the same weight class, or Dyneema Composite Fabric (DCF) — a non-woven laminate — for the lowest weight per unit of strength.
Standard nylon (nylon 6 or nylon 6,6) is a woven synthetic fiber, the default material for internal-frame packs from brands like Osprey, Gregory, and REI Co-op. Ripstop nylon weaves a thicker reinforcing thread into the base fabric every few millimeters, so a small tear stops at the next grid line instead of spreading across the panel. A PU or silicone coating on the fabric's inside face adds water resistance without changing the weave; silicone-coated nylon (silnylon) is another option, used on some ultralight packs.
Cordura is a branded family of fabrics, many built on high-tenacity nylon, engineered specifically for abrasion resistance relative to weight. It's not a single fabric but a range — standard Cordura, Cordura ripstop, and heavier ballistic-weave variants — used on high-wear zones like pack bottoms as often as on entire pack bodies.
Dyneema Composite Fabric (DCF), formerly sold as Cuben Fiber, is a laminate rather than a weave: a grid of ultra-high-molecular-weight polyethylene (UHMWPE) fibers sandwiched between thin polyester film layers with an adhesive. It doesn't stretch, doesn't absorb water, and carries an exceptional strength-to-weight ratio, which is why Hyperlite Mountain Gear, Zpacks, and Mountain Laurel Designs built product lines around it. Dyneema Composite Hybrids, a newer category of hybrid fabrics, add a non-Dyneema face fabric to the Dyneema core for extra abrasion resistance or flexibility.
Dyneema Composite Fabric is the lightest option and doesn't absorb water, but it costs the most and is less forgiving of a sharp puncture than a woven fabric. Standard nylon is the cheapest and most widely used pack material. Cordura nylon trades a small weight penalty for meaningfully better abrasion resistance than standard nylon at a comparable price.
These three materials sit on a clear spectrum of weight, cost, and toughness. Compare them directly:
| Fabric | Typical weight | Abrasion resistance | Water behavior | Typical cost tier |
|---|---|---|---|---|
| Standard nylon | Moderate | Fair to good | Absorbs some water, coating sheds rain | Budget to mid-range |
| Cordura nylon | Moderate to heavy | Very good | Absorbs some water, coating sheds rain | Mid-range to premium |
| Dyneema Composite Fabric (DCF) | Lightest | Good along fiber grid, weak against sharp punctures | Does not absorb water | Premium |
Nylon's main weakness is that the fiber itself absorbs a small amount of water, so a worn-coating nylon pack gains noticeable weight in sustained rain. Cordura addresses toughness, not water absorption — it's still nylon at its core, just woven and finished for higher abrasion resistance. DCF sidesteps both issues, but a puncture or a deep cut from a sharp rock edge can propagate through a DCF panel in a way a tightly woven ripstop nylon sometimes resists.
No hiking backpack fabric is fully waterproof once the whole pack is considered, because seams, zippers, and pocket openings let water in even when the base fabric itself sheds it. DCF comes closest at the fabric level since it doesn't absorb water, but most hikers still pack a liner for guaranteed dry gear.
A pack's water resistance is a system property, not just a fabric property. A DCF pack with taped seams and a roll-top closure resists water well at the main compartment, but a zippered hipbelt pocket with a standard (non-waterproof) zipper lets water through regardless of what the body is made from. Coated nylon packs are water-resistant in light rain but wet through in sustained downpours or stream crossings, since the coating only slows water absorption rather than blocking it, and stitched seams are rarely taped on mainstream nylon packs. The standard workaround, regardless of fabric, is a pack liner — a heavy-duty trash-compactor bag or a dedicated dry-bag liner lining the main compartment — because relying on the shell alone is unreliable once rain lasts more than an hour or two. A pack cover helps keep the fabric itself dry but does little for zippers and rarely covers the back panel against the hiker's body, so it works best paired with a liner rather than instead of one.
Denier measures the thickness of the yarn used to weave a fabric — grams per 9,000 meters of thread — and higher denier generally means more abrasion resistance and more weight. It's one input into durability, not the whole picture; weave pattern, coating, and fiber type matter just as much.
Pack spec sheets often list a number like 100D, 210D, 420D, or 1000D next to the fabric name. Ultralight pack bodies commonly run 100D to 210D nylon or Cordura to hold weight down. High-wear zones — pack bottoms, side panels that brush against rock, the area under a hipbelt buckle — commonly step up to 420D, 500D, or 1000D+ on the same pack, since abrasion damage concentrates in a few predictable spots rather than spreading evenly. A higher denier number doesn't automatically mean a ripstop weave; ripstop refers to the reinforcing grid thread pattern, woven into fabrics across a wide range of deniers. Two packs both listing 210D nylon can still wear differently depending on whether the yarn is high-tenacity nylon 6,6 or a lower-grade nylon 6. Denier is a useful comparison point between two fabrics of the same type, but it doesn't translate across fabric families — a 150D DCF-hybrid face fabric and a 150D standard nylon do not perform the same way against a granite scramble.
Go Deeper
Detailed companion guides for materials & fabrics.
Best Dyneema (DCF) Backpacks
Buyer's guide: best dyneema backpack.
Best Cordura Backpacks
Buyer's guide: best cordura backpack.
Dyneema vs Nylon vs Cordura
Dyneema, nylon and Cordura compared for weight, abrasion resistance, cost and water behavior, so you can match pack fabric to how and where you hike.
Pockets & Organization
Related features, frames & materials guide.
Hydration Compatibility
Related features, frames & materials guide.
Reading the denier number properly
Denier has a precise definition: the weight in grams of 9,000 meters of yarn, normally used for filament yarns, and a higher number means a heavier yarn. Some spec sheets use decitex instead, which converts at about 1.11 decitex per denier.1 What denier does not capture is tenacity, the strength of a yarn for its weight. US tariff rules treat a single nylon or polyester yarn as high-tenacity only when its tenacity exceeds 60 cN/tex, a property separate from its denier.1
That is why a label like high-tenacity 210D can tell you more than the number alone, and why comparing two fabrics by denier only works within the same fiber family, as this page notes. Fiber chemistry differs too. Under US labeling rules, nylon is defined as a manufactured fiber made from a long-chain synthetic polyamide, and polyester as a long-chain synthetic polymer that is at least 85% by weight an ester of a substituted aromatic carboxylic acid.2 Two fabrics with the same D number can be quite different materials.
What Dyneema composite actually is
Dyneema is a brand of ultra-high-molecular-weight polyethylene (UHMWPE) fiber.3 Its maker says every Dyneema composite fabric is built on a core of Dyneema fiber layers bonded at 0 and 90 degrees, and Zpacks describes the result as Dyneema threads laminated to a polyester membrane.4,5 Dyneema states its fiber is 15 times stronger than steel yet light enough to float on water, and Hyperlite gives a similar strength-to-weight figure. Both are manufacturer claims about the fiber, not measurements of a finished pack panel.3,6
Dyneema says the composite won't tear like pure polyester or nylon, won't absorb water and won't sag or stretch over time. It also offers hybrids that add a non-Dyneema face fabric to the core for extra abrasion resistance or flexibility, the category this page calls hybrid fabrics.4 Hyperlite states its newer woven Dyneema composite is more abrasion- and tear-resistant than its previous fabrics, a sign that abrasion was the trade-off makers were working on.6 The page's point that DCF is weaker against sharp punctures is a common view among hikers, but no source in this site's library tests it directly.
Coatings, DWR and the move away from PFAS
DWR, short for durable water repellent, is an invisible finish on the outer fabric that makes water bead up and roll off. Nikwax says ordinary laundry detergents leave a water-attracting residue on outdoor fabrics.7 It also says UV exposure destroys water repellency and reduces fabric tear strength.8 Deuter's simple check: drop water on the fabric, and if it soaks in rather than beading, it is time to reproof.9
Many water-repellent finishes have relied on PFAS, a large family of long-lasting chemicals whose components break down very slowly, and the EPA lists stain and water repellents on fabrics as a PFAS source.10,11 California's AB 1817 explicitly lists backpacks as textile articles and, from January 1, 2025, bars new textile articles containing regulated PFAS, with a threshold of 100 ppm total organic fluorine that drops to 50 ppm in 2027.12 Other states set different rules and dates, so a PFAS-free label is increasingly common but not yet a single nationwide requirement.