The Best Guy Lines: 4 Compared (and One to Skip)

RBE top pick

Lawson Reflective Glowire Cord

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The Glowire wins because 2mm is the diameter that suits most shelters, it is sold by the hank so you cut what you need, and the reflective tracers are braided into the jacket instead of printed on. The Z-Line is the one to take if every gram counts and your guylines are short.

Guy line is the cheapest thing holding your shelter up and the part most people inherit rather than choose. The category splits in two before you get anywhere near the specification. You can buy cord on a hank, cut it to length and add your own adjusters, or you can buy a finished set with fixed lengths and the hardware attached. The first is cheaper per foot and fits any shelter; the second removes the knot-tying and is sized for somebody else's tent. We took two of each and read what the makers publish.

RBE top pick

Lawson Equipment

Reflective Glowire Cord

Buy it

Two millimetre kernmantle cord with retroreflective tracers braided into the jacket, sold by the hank so you rig it to your own shelter.

Best for: Anyone rigging their own shelter who wants one cord that suits tents, tarps and awnings alike.

$$ · mid-range

Why we like it

• 2mm diameter, which is the usual size for tent and tarp guy-outs on anything larger than an ultralight shelter.
• 3M Scotchlite reflective tracers work like a road sign, throwing light straight back at a headlamp, so the brighter the beam the more the line shows up.
• Lawson states it now uses the UltraFuzion jacket, the same jacket it has used on its Ironwire cord for years.
• Sold in 50 foot and 100 foot hanks, a 300 foot spool (500 feet in black), in six colours, with a stated 225 lb average break strength at 2mm.
• Braided in house on Lawson's own machines, which is why the construction detail is on the page at all.

Know before buying

• You supply the adjusters and tie the knots, so the finished cost is higher than the cord price suggests.
• At 2mm it is heavier than the ultralight cords, which matters if you are guying out a tarp for a thru-hike.
• No weight per length on the product page.
• Cutting from a hank means sealing the ends yourself or watching them fray.

Find it on Amazon Read our detailed assessment ↓

Zpacks

Z-Line Reflective Cord, 1.3mm

Buy it

Fifty feet for a stated 23 grams, with 3M Scotchlite tracers, and a maker that tells you what the diameter is not good for.

Best for: Ultralight shelters with short fixed guylines where 23 grams per 50 feet is worth the handling penalty.

$$ · mid-range

Why we like it

• Zpacks lists 50 feet at 23 grams in the 1.3mm size (21 grams for the cord in its spec table), with a 187 lb breaking strength.
• Reflective tracers are 3M Scotchlite, named rather than described generically, as Lawson also does.
• Abrasion and UV resistant polyester jacket over a high-tenacity polyester core, so it resists both sun and stretch.
• Zpacks says it is tangle resistant, which is a real property of a stiff thin cord and a genuine annoyance in the ones that are not.
• Zpacks pairs it with its own Micro Linelocs, so the hardware question has an answer.

Know before buying

• Zpacks states outright that 1.3mm suits shorter fixed-length guylines, so it is the wrong choice for long tarp guy-outs.
• Thin cord is harder on the hands when you are tensioning in the cold.
• One diameter and one length per listing, with no hank or spool option.

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Sea to Summit

Ground Control Guy Cords, 4 Pack

It depends

A finished four-pack with quick-connect toggles and built-in adjusters, at fixed lengths chosen for Sea to Summit's own tents.

Best for: Owners of Sea to Summit Alto or Telos tents, and anyone who wants guy lines that work without learning a knot.

$ · budget

Why we like it

• Quick-connect V-toggles that Sea to Summit says eliminate the need for knots entirely.
• An integrated adjuster on each cord, so tensioning is a slide rather than a taut-line hitch.
• Reflective, which Sea to Summit frames as much about not tripping over them as about finding the tent.
• The set is two 2.2m and two 1m nylon cords at a stated 18 grams, and cords can be joined together for extra length.
• Supplied as standard with the Alto and Telos tents, so they are a known quantity with that hardware.

Know before buying

• Fixed lengths sized for particular tents, so they may be too short or long for yours.
• The V-toggles need a compatible guy-out point to connect to.
• No published cord diameter, which makes it hard to compare against cord sold by the metre.
• Four cords is fewer than a well-guyed shelter needs in wind.

Check price on Amazon Read our detailed assessment ↓

We'd skip it

MSR

Reflective Utility Cord Kit

Skip it

A reflective, knot-free 3mm cord kit with four tensioners, priced well above the rest, with no breaking strength or weight on MSR's page.

Best for: Replacing a lost guy line on an MSR tent where the original length is already known.

$$$ · premium

Why we like it

• 15m (49.2ft) of 3mm reflective cord with four CamRing tensioners, so the kit works out of the packet.
• MSR describes it as knot-free, which is the useful property of a kit over raw cord.
• MSR pitches it for bear bags as well as tarp guy-outs, so it doubles as general utility cord.

Know before buying

• The most expensive option here by a distance, for one 15m length of cord and four tensioners.
• No published weight, so you cannot compare it against the Zpacks or Sea to Summit figures.
• At 3mm it is the thickest cord here, more than most tent guy-outs need.
• MSR publishes no breaking strength, where Lawson and Zpacks both print one, so you cannot tell what load the cord is rated for.

See our pick instead See it at Amazon anyway Read our detailed assessment ↓

How we judged the field

Five things decide a guy line and the first is not the cord at all. It is whether you are buying raw cord or a finished set, because that determines whether you can cut it to your shelter or have to live with somebody else’s lengths. The second is diameter, which sets how the cord handles in the cold and how much load it will take. The third is weight, which is the price of that diameter and the reason the ultralight cords exist. The fourth is how the reflective element is made, because tracers braided into a jacket last and a printed coating does not. The fifth is what the cord expects you to do about tension: tie a knot, add your own adjuster, or use hardware that came attached.

The field splits cleanly along the first of those, so we took two from each side. Lawson and Zpacks sell cord, with the diameter and a breaking strength printed on the page, and leave the hardware and the cutting to you. Sea to Summit and MSR sell finished kits, with adjusters and toggles included and the cutting already done. Sea to Summit states the four lengths in its set and the weight of the set but no diameter. MSR states a 3mm diameter and a 15m length but no weight, and it costs far more than the others, which is what puts it at the bottom of this comparison.

The Glowire is the cord we would buy for a shelter we intended to keep. Lawson sells it at 2mm, which is the diameter that suits most tents and tarps, on hanks of 50 and 100 feet and a 300 foot spool (500 feet in black), with a stated 225 lb average break strength. The reflective element is the interesting part: the 3M Scotchlite tracers are braided into the jacket rather than applied to the surface, and Lawson describes them working like a road sign, so the brighter the light you shine the more the cord throws back. That is retroreflection rather than a glow, and it is the property that makes a guy line visible from across a campsite. Lawson has also moved the cord onto its UltraFuzion jacket, the same one it has used on Ironwire for years, and says it braids in house on its own machines, which is why there is construction detail on the page at all. The costs are plain. You buy adjusters separately, you tie your own knots, and at 2mm it is much heavier than the Zpacks cord.

The Z-Line is the ultralight answer and the one whose page tells you where not to use it. Zpacks lists 50 feet at 23 grams in the 1.3mm size, with a 187 lb breaking strength and 3M Scotchlite tracers named specifically rather than described as reflective. The construction is an abrasion and UV resistant polyester jacket over a high-tenacity polyester core, which addresses the two things that actually kill guy line: sunlight and stretch. Zpacks also says it is tangle resistant, which sounds like filler until you have spent five minutes in the rain unpicking a thin cord. What makes this listing better than most is the caveat: Zpacks writes that the 1.3mm size is better for shorter fixed-length guylines, which is the maker telling you its own product has a range. Pair it with the Micro Linelocs from the same shop and you have a complete system; buy it for long tarp runs and you have bought the wrong diameter.

The Ground Control cords are the finished option done properly, within limits they are open about. The set is four cords, two at 2.2m and two at 1m, at a stated 18 grams, each with an integrated adjuster so tensioning is a slide rather than a knot. The distinctive part is the quick-connect V-toggle, which Sea to Summit says removes the need for knots entirely, and cords can be joined to one another when you need a longer run. They ship as standard with the Alto and Telos tents, and that is the clue to who should buy them: the lengths were chosen for those shelters. On a different tent you may find the 1m cords reach nothing useful. There is also no published diameter, so you cannot line them up against cord sold by the metre, and four cords is fewer than a shelter needs when you are guying it out properly against wind rather than adding a couple of lines for tidiness.

The Reflective Utility Cord Kit is the one we would leave. MSR describes 15m (49.2ft) of 3mm reflective cord with four CamRing tensioners, pitched for bear bags as well as tarp guy-outs, which is the right idea and makes it knot-free out of the packet. The problem is value and documentation. It costs far more than a Lawson hank or the Zpacks cord, it gives you one length to cut rather than a choice, and MSR publishes neither a weight nor a breaking strength, the one figure that tells you what a guy line will hold in a gust. As a like-for-like replacement on an MSR tent it is sensible; as a general purchase the two cords above do more for less.

Lawson Equipment Reflective Glowire Cord vs Zpacks Z-Line Reflective Cord, 1.3mm: which should you buy?

The Glowire and the Z-Line are the two to choose between, and the question is the length of your guy-outs rather than your taste in cord. Lawson’s 2mm, rated at a 225 lb average break strength, is the general answer: it handles well in cold hands, it suits a tarp run as readily as a tent guy-out, and it comes on a hank so you cut what the shelter needs. Zpacks’ 1.3mm at 23 grams per 50 feet is the ultralight option, and Zpacks is clear that it earns that on shorter fixed lengths.

The other difference is what surrounds the cord. Lawson publishes its construction, its jacket and its colour range, and expects you to bring your own hardware. Zpacks sells Micro Linelocs from the same shop, so the system is already assembled if you want it. Both use 3M Scotchlite tracers rather than a coating. If you own one shelter and want one cord for it, buy the Lawson by the hank. If you are counting grams on a shelter with short guylines and already own linelocs, the Z-Line is the better fit and the lighter one.

What to look for

• Decide raw cord or finished set first: it governs whether you can match the lengths to your shelter or have to live with somebody else’s.
• Look for a diameter in millimetres: 2mm suits most shelters, and anything near 1.3mm is an ultralight choice with handling costs.
• Check weight per length, not per item: a figure like 23 grams per 50 feet is the real comparison, and a set weight tells you nothing about cost per metre.
• Prefer tracers braided into the jacket: a reflective coating wears off, and only some makers say which they used.
• Budget for adjusters if you are buying cord: a hank plus a set of linelocs is a different price from the hank alone.
• Count your guy-out points before you buy a set: four fixed cords rarely covers a shelter you are actually trying to hold down in wind.

Our final take

Guy line is bought once and cursed at three in the morning, which is a good argument for spending a few minutes on it. The split that matters is between cord and kit, and the cord makers publish the most: a diameter and a breaking strength from both, plus a weight per length from Zpacks. Lawson’s Glowire at 2mm is the sensible default, sold by the hank so it fits your shelter rather than somebody else’s. Zpacks’ Z-Line is the right call when grams matter and the runs are short, and the page is honest about that limit. And a utility cord kit that costs far more than either cord, with no published weight, is asking you to buy on the badge.

Deciding between the top two? See our head-to-head: Lawson Equipment Reflective Glowire Cord vs Zpacks Z-Line Reflective Cord, 1.3mm.

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