Guylines are one of the smallest components on an ultralight shelter, and one of the easiest to get wrong. Buy cord that’s too thin and it stretches, saws through your fingers when it’s under load, or simply snaps in a gust. Buy cord that’s too thick and you’ve quietly added grams you didn’t need to carry for a job that a strand half the diameter could handle. Dyneema cordage solved most of the strength-to-weight problem the moment it replaced braided nylon on tarps and trekking-pole tents, but it created a new question: which thickness actually matches which job? This guide breaks down the sizes that matter, what they’re rated to hold, and where each one belongs on your shelter.
Why Dyneema Replaced Nylon for Guylines
Ultra-high-molecular-weight polyethylene, sold under the Dyneema brand, has a strength-to-weight ratio that beats steel wire by a wide margin while floating on water. For cordage specifically, three properties matter more than raw tensile strength. First, it has essentially zero stretch under load, which means a guyline stays tensioned all night instead of sagging as nylon does when it gets damp. Second, it doesn’t absorb water, so it won’t swell, freeze stiff, or add weight in the rain the way nylon or polyester cord can. Third, at a given breaking strength it’s dramatically thinner and lighter than any nylon equivalent, which is why a full set of guylines on an ultralight shelter can weigh next to nothing.
The tradeoff is handling. Dyneema is slick, and a taut-line hitch that holds fine on nylon will slip on bare Dyneema cord. That’s a solvable problem (more on that below), but it’s worth knowing going in rather than discovering it at camp.
Dyneema Cord Thickness Chart
Manufacturers don’t use identical diameters, so treat these as ranges rather than exact standards. Here’s roughly where the common sizes land and what they’re built for.
- 1.0-1.2mm: Roughly 100 to 200+ lbs breaking strength depending on the brand’s braid. This is the lightest category, sold by brands like Zpacks as their thinnest Z-line. Good for guylines on single-wall trekking-pole shelters and tarps where wind load is moderate.
- 1.3-1.6mm: Around 200+ lbs breaking strength. This is the most common “do everything” guyline thickness, thick enough to grip comfortably with cold or gloved hands and still light enough that a full set of six to eight guylines barely registers on a gear list.
- 1.75mm: Roughly 500 lbs breaking strength, the range occupied by Zing-It/Lash-It style cordage. This is a step up meant for ridgelines, hammock suspension, and situations where you want a real safety margin rather than the minimum that will hold.
- 2.0-2.2mm: 200+ lbs up to roughly 650 lbs depending on construction. At this thickness you’re usually buying rated strength for hammock ridgelines or heavy-duty tarp ridgelines, not for standard stake-out guylines, where it’s overkill.
Weight differences between these sizes are small in absolute terms, often a fraction of a gram per foot, but they add up across a full guyline kit and matter more than the numbers suggest once you’re comparing complete shelter setups.
The Sweet Spot for Everyday Guylines
For the guylines that hold out a trekking-pole tent, a pyramid shelter, or a simple A-frame tarp, 1.2mm to 1.6mm Dyneema cord is the range almost everyone should default to. It’s strong enough to handle real wind loading with margin to spare, thin enough to pack flat without adding bulk, and easy to tie off with a simple adjustable knot once you know the right one for slick cord. Going thinner than 1.2mm mostly saves weight you won’t notice while making the cord harder to grip and more prone to cutting into your fingers when you’re tensioning it in the cold.
One detail worth checking before you buy: reflective versus non-reflective. Reflective Dyneema cord has a thin strip of 3M Scotchlite woven into the sheath, so a headlamp beam picks it up instantly at night, which matters more than it sounds like when you’re navigating a crowded tent site or trying not to trip a neighbor’s guyline in the dark. It typically costs slightly more and comes in marginally thicker constructions than the plain slick version, but for most hikers the safety and convenience upside is worth the small tradeoff.
Ridgelines and Hammock Suspension: Where 1.75mm and Up Belongs
A ridgeline or hammock suspension line is doing more work than a guyline, and it’s doing it continuously rather than intermittently. A tarp ridgeline under a heavy, wet fabric in wind, or a hammock suspension bearing a hiker’s full body weight, benefits from the extra safety margin that 1.75mm cordage like Zing-It or Lash-It provides. This is also where you want to be more conservative about breaking strength ratings in general: a stated breaking strength is a lab number under controlled conditions, not a real-world safety factor, so building in headroom matters more here than on a simple stake-out line. For hammock ridgelines specifically, many hikers step up even further to 2.0mm or 2.2mm cordage, trading a small amount of weight for a strength margin they don’t want to think twice about at 2 a.m.
Repair Cord and Small Utility Uses
Thin Dyneema cord, generally under 1.2mm, also earns a spot in a repair kit or as drawcord replacement on stuff sacks, food bags, and pack pockets. It’s strong enough to replace a broken zipper pull cord or a snapped drawstring without adding meaningful weight to a repair kit, and a short length wound onto a mini bobbin costs almost nothing to carry. This isn’t the cord to rely on for load-bearing repairs like a broken pack strap, but for small fixes on the trail it’s hard to beat.
Knots That Actually Hold on Dyneema
Because Dyneema cord is so slick, a standard taut-line hitch will often creep or slip under tension, which is the single most common complaint from hikers switching over from nylon guylines for the first time. A few workarounds solve this reliably: a Prusik loop tied with a separate short length of cord grips well because it relies on wraps rather than friction against a single strand, and it’s the standard fix on hammock ridgelines. For simple stake-out guylines, a purpose-built line-lock or tensioner (the small plastic or aluminum toggles included with most ultralight tarps and tents) sidesteps the knot problem entirely and is worth using even if you’re comfortable tying knots on other materials.
Frequently Asked Questions
Does Dyneema cord stretch under tension?
Effectively no. Dyneema has one of the lowest stretch percentages of any cordage material, which is exactly why it holds tension overnight better than nylon paracord, which can stretch several percent when wet and loosen a pitch by morning.
Can I just use paracord instead of Dyneema for guylines?
You can, and plenty of budget setups still do, but you’ll carry more weight for the same strength and you’ll likely need to retighten guylines after rain or overnight dew since nylon stretches when wet. Dyneema cord costs more per foot but the weight and tension advantage is one of the easier upgrades to justify on an ultralight shelter.
What thickness should I buy if I only want one spool for everything?
1.5mm to 1.6mm is the most versatile single choice. It covers guylines comfortably, works for most repair uses, and is only marginally too thin for a true ridgeline application if you’re careful about knots and hardware.
Is thicker Dyneema cord always stronger?
Generally yes within the same product line, but construction matters as much as diameter. A 1.75mm cord built specifically for high load, like Zing-It, can be rated well above a 2.0mm cord from a different manufacturer using a different braid, so compare stated breaking strength rather than diameter alone when it matters.
Building Out a Guyline Kit That Actually Matches Your Shelter
Matching cord thickness to its job is a small decision compared to choosing a tent or a pack, but it’s the kind of detail that separates a shelter setup that survives a rough night from one that doesn’t. If you’re building or upgrading a shelter system from scratch, it’s worth reading through our guide to A-frame and pyramid tarp pitching alongside this one, since guyline choice and pitch geometry are closely linked. For anyone considering sewing their own shelter rather than buying one, our Dyneema vs. Tyvek comparison for DIY makers covers the fabric side of that same decision, and our deep dive on Dyneema fabric is a good primer if you’re new to the material generally.
Small components like guylines are also exactly the kind of thing that gets lost in a gear closet or forgotten during a repack, since they’re easy to overlook next to a tent body or a sleeping bag. That’s part of why we built FeatherPack, an iOS app where you photograph one piece of gear at a time and it recognizes the item and logs its weight into your inventory automatically. Once your guylines, stakes, and shelter are all logged, you can pull them into a trip-specific pack list and see your real total weight before you leave the driveway, instead of guessing.
What thickness are you currently running on your shelter, and has switching to Dyneema cord actually changed how your pitch holds up in wind? Drop a comment below, we’re always curious what’s working for other hikers out there.
