Advanced (read: non-nylon) woven fabrics have spent most of the past decade promising to upend standard performance to weight ratios, especially where backpacks are concerned. Standard and hybrid cuben laminates have been a disappointment in this respect, with inadequate durability and poor balance between performance and cost. The hype and rhetoric associated with hybrid cuben packs, most specifically the marketing prowess of Hyperlite Mountain Gear, has made a (perhaps the most) significant contribution towards mainstreaming non-traditional pack fabrics, which has resulted in larger interest and market share, and thus the development in recent years of more diverse options in pack fabrics.
Challenge fabrics Ultraweave* is the most interesting pack fabric of the past decade, due to both specs and availability. 100% woven dyneema has been around for almost all of that decade, and used as a halo product by several manufacturers, but maintaining this status has prevented it from being widely available, either as fabric or as a finished product. Ultraweave, which is 2/3 pure dyneema (in essence) and 1/3 polyester promises to be a functional equivalent. 400D Ultra, for instance, claims 7600 taber cycles** and 200+ psi waterproofing at 4.65 ounces a yard. VX42, by contrast, is 9.3 ounces a yard, an tests to 1700 cycles, while 1000D Cordura is 9.8 oz/yrd, tests to 4000 cycles, and is (approximately) 3 psi waterproof. 800D ultra is 8.1 oz/yrd, and tests to a staggering 10500 cycles. VX42 has in the roughly 8 years it’s been widely available been my benchmark for a durable pack fabric, meaning that it is adequate for many years of consistent application in all but the most extreme uses, by which I mean canyoneering and severe scrambling and bushwacking. Doubling that abrasion resistance while halving the weight is a paradigm altering proposition.
I’ve been working with Superior Wilderness Designs since this spring, testing their new Big Wild load hauler. Earlier this month I received a proto Big Big Wild, 110 liters, made from 400d Ultraweave with an 800D bottom. My instructions were to break it, if at all possible. The first few trips suggested that this would not be easy. Bushwacking and talus dragging did nothing. back surfing down cutbanks and rolling a loaded pack down hills left it similarly unscathed. I went old school on a recent trip and lashed the loaded pack to the front of my packraft, a good reminder that running (and portaging) class IV with such an arrangement is less than ideal. This did confirm that Ultra is as waterproof as claimed, and reinforced my main interest in D-P fabrics, back in the pre-cargo fly era. As a side benefit, the past weeks dirt was rinsed clear and the fabric looked brand new.
It was obvious at this point that absent a slot canyon trip, field use was going to take years to significantly stress the fabric. So I resorted to backyard testing.
We live on a paved road downtown, with steep side streets and alleys that have been left gravel due to how icey they’d be in the winter. They are not graded often, and have plenty of ruts, grass, small, rocks, big rocks, and potholes. My first test rig involved clipping the grab handle to the trailer hitch. The pack, stuffed full of heavy blankets***, flopped sideways easily, which was good for testing the sides and side pockets, but didn’t concentrate forces on the base/front interface, whose fabric transition was my primary interest. It took three laps, increasing in distance, to make a dent in the fabric, and to refine methods and better control the wear area. I ended up with cord strung across the open hatchback from the rear roof rack bar, with locking carabiners clipped to side compression straps. The fourth and final lap, with the pack finally secured as I wanted it, was 7/10ths of a mile. The total test distance from the four laps was just short of 2 miles. I made sure to not exceed 10 mph, both for safety****, and to eliminate friction/heat buildup as a source of stress.
The damage report was modest. The second trial got a golf ball sized elliptical hole on the roll top, unsurprising, given the hard plastic in the stiffener. This trial also wore halfway through a 3/4″ webbing compression strap where it ran against the buckle. The final, long trial put a pin sized hole in one bottom corner, and wore notably into the bottom daisy chain, though not to the point of being a structural issue. The 400D fabric was fuzzed up in many areas, while the 800D was essentially unscathed. Of greatest interest, the side pockets, which were empty but consistently collected dust and rocks in the first three trials, had no holes or significant abrasions, in spite of the extensive folding caused by the drawcord being cinched. Aside from patching the one hole, the pack was functionally unscathed. Consistent with field use, a large amount of the dirt staining washed out when blasted my a hose, leaving the pack at a distance looking essentially new.
In summary, Ultraweave lives up to its specs, and to Challenges’ claims of it being as good or better than anything on the market. The 400 and 800D are certainly the toughest fabrics for the weight I’ve ever seen, with the 800 being clearly tougher than anything else I’ve used, and the 400D probably being as good if not better than the traditional big guns, 1680D ballistics nylon and 1000D cordura. The question for consumers will be, is this fabric worth the increased cost? Rockywoods is currently selling Ultra fabrics as Diamondhide, for 15 dollars a foot. SWD charges 35 dollars more from a 50 liter Long Haul pack in Ultra, as opposed to more conventional poly face fabric laminate. This distinctly non-halo upcharge makes that particular option an easy choice.
*Challenge currently has their v3 spec sheet posted on their website, which lists drastically reduced taber numbers. I have the v8 sheet, from which these numbers are taken. As discussed here my testing supports the higher figures.
**In my frankly extensive experience abrasion resistance is by far the most important metric in a heavy use pack fabric. Ultra tear numbers are similarly high, 114/117 lb and 187/161 lb for the 400 and 800. 1000D Cordura is 54/47 (tear, not tensile), for reference, and for me anything about 40 lb is effectively bulletproof.
***To simulate a decent load without any point loading and abrasion.
****I had both kids in the back seat as QC observers of pack and camera position.