Big Agnes’ Onxy Tarp is a square tarp designed for ultralight backpacking and bikepacking. Weighing 8.1 oz, it’s seam taped and fully outfitted with guy lines and tensioners out of the box, so you don’t have to buy anything extra to start using it. The tarp also includes a short pole which is useful for pitching the shelter if you don’t carry trekking poles, and can also serve as a spreader bar to create more headroom if you use the use the tarp with a hammock or for two people. Tarp camping is ideal if you want to minimize the weight and bulk of your gear for ultralight backpacking or bikepacking.
Specs at a Glance
- Type: symmetric square tarp
- Weight of tarp: 8.1 oz (including guylines, cord tensioners)
- Weight of optional pole/spreader bar: 1.6 oz (length – 40.5″)
- Dimensions: 8’6″ x 8’6″
- Number of guy-outs (5 per side), 16 total
- Material: PU coated, silicone-treated nylon ripstop, 1200mm
- Seam-taped: Yes
The Onyx is a square tarp meaning that the sides have equal length and the corners are right angles. Square tarps are relatively rare compared to rectangular tarps or catenary cut tarps which have curved ridgelines or edges to save weight and reduce flapping. Square tarps are however wonderfully versatile and can be configured in all kinds of different pitches or shapes, although it requires considerable practice and skill to make them. Most of the time, people still set them up in an A-frame configuration, which is easy to master, and very fast to set up.
While the Onyx is made with PU coated silicone treated nylon, it is still very lightweight, even when compared to a similarly sized square tarp made with Dyneema Composite Fabrics (formerly called cuben fiber). It also stuffs up quite small, a bit smaller than a Nalgene bottle, making it very easy to carry in a low volume ultralight backpack or in a bikepacking bag, where space is at a real premium.
All of the guy out points on the Onyx are made with short lengths of green webbing which is box-tacked and reinforced on the seam, in addition to external panel guy outs to help expand interior volume. The corners and centers guy outs on each side also have separate Hypalon tabs, also box-tacked to the hems, that are laser cut to accept the optional pole tip. There are four additional Hypalon tabs attached to the interior panels of the tarp, that can accept the tips of the spreader bar, if you want to increase interior volume. This can be especially helpful if you use the Onyx as a hammock tarp (on the diagonal) or as an A-frame shelter for two people.
The Onyx comes pre-guyed with lightweight cord and triangular guy line runners, so you can start using the tarp right away without having to outfit it. The center seam is also taped, so there’s no seam sealing required.
Comparable Square Tarps
|Make and Model||Dimensions||Weight||Material||Price|
|Big Agnes Onyx Tarp||8'6" x 8'6"||8.1 oz||silPU||$280|
|Hyperlite Mountain Gear||8'5" x 8'5"||8.85 oz||DCF||$355|
|Mountain Laurel Designs Supertarp||10'x10'||19 oz||silnylon||$245|
|Yama Mountain Gear||8'5" x 8'5"||13.9 oz||silpoly||$140|
The Big Agnes Onyx Tarp is an ultralight square tarp that can really hold its own in terms of price, gear weight, and versatility, even when compared to ultralight tarps made by cottage manufacturers. Suitable for backpacking, hammocking, and bikepacking, the square Onyx is large enough for use by one or two people and even includes an optional pole for setup if you don’t carry trekking poles. It’s also outfitted for immediate use with a seam-taped ridgeline, guy lines, and line runners, which is a nice touch you don’t often see when purchasing a tarp and adds a lot of value.
Big Agnes provided a tarp for this review. Published 2018.Editor's note: Help support this site by making your next gear purchase through one of the links above. Click a link, buy what you need, and the seller will contribute a portion of the purchase price to support SectionHiker's unsponsored gear reviews, articles, and hiking guides.
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