Explained
Guy Lines, Explained
After reading, you'll know which diameter suits your shelter, how much cord to buy, and whether you need adjusters.
In this guide
Guy line looks like the one part of a shelter you cannot get wrong, which is why most people are still using whatever came in the bag. The two decisions are the diameter, which sets how the cord handles and how much load it takes, and whether you buy cord you cut yourself or a finished set with the hardware attached. Everything else, including the reflective tracers that stop you walking into it at night, follows from those.
The 30-second version
- 2mm is the general answer, thick enough to tension with cold hands and strong enough for a shelter in wind.
- Ultralight cord has a stated range, and at least one maker says plainly that its 1.3mm suits only shorter fixed-length guylines.
- Tracers beat coatings, because reflective material braided into the jacket survives the abrasion that wears a coating off.
- Raw cord needs hardware, so price a hank alongside a set of linelocs rather than against a finished kit.
- Fixed-length sets are sized for a particular tent, which is fine if it is your tent and awkward if it is not.
The products this guide is about
Our verdict on each, with the full reasoning on the companion review.
- Buy Lawson Equipment Reflective Glowire Cord Two millimetre kernmantle cord with retroreflective tracers braided into the jacket, sold by the hank so you rig it to your own shelter.
- Buy Zpacks Z-Line Reflective Cord, 1.3mm Fifty feet for a stated 23 grams, with 3M Scotchlite tracers, and a maker honest enough to tell you what the diameter is not good for.
- It depends Sea to Summit Ground Control Guy Cords, 4 Pack A finished four-pack with quick-connect toggles and built-in adjusters, at fixed lengths chosen for Sea to Summit's own tents.
- Skip MSR Reflective Utility Cord Kit A reflective knot-free cord kit from a maker that normally publishes everything, and here publishes almost nothing.
What actually matters
- Diameter - the thickness of the cord in millimetres. It determines handling in the cold, how much load the line takes, and how well adjusters grip it. The single most useful number on the page.
- Weight per length - grams per 50 feet or per metre, which is the only fair way to compare cord. A weight for a finished set tells you nothing about cost per metre.
- Reflective method - tracers braided into the jacket, or a coating applied to the surface. Braided tracers last; coatings abrade off where the cord runs through hardware.
- Core and jacket construction - kernmantle cord has a load-bearing core inside a protective sheath. A UV resistant jacket matters because sunlight is what ages guy line that never breaks.
- Stretch - low-stretch cord holds tension overnight. A stretchy line goes slack as it absorbs moisture and temperature change, which is why you wake up to a sagging fly.
- Adjuster type - a lineloc, a V-toggle, or a knot. Hardware matters most when you are retensioning in bad weather with cold hands.
- Length supplied - a hank you cut, or fixed lengths chosen by the maker. Count your guy-out points before deciding which is enough.
The specs, in plain English
Green flags vs red flags
Green flags
- A diameter in millimetres stated on the page.
- A weight given per unit length rather than per item.
- The reflective material named, such as a specific tracer type.
- The maker stating what the cord is and is not suited to.
- Compatible adjusters sold by the same maker, so the hardware question is answered.
Red flags
- No diameter anywhere in the listing.
- No length stated on a finished kit, so you cannot tell if it reaches.
- Reflectivity described only as a feature with no indication of how it is applied.
- A product description short enough to fit in a sentence.
- A set weight quoted as though it were comparable to cord sold by the metre.
Who's who: the brands
- Lawson Equipment - Braids its own cord in house and publishes construction detail, jacket type and weight per hank, in diameters suited to general shelter use.
- Zpacks - Ultralight specialist that states weight per 50 feet, names its reflective material, and says plainly which guyline lengths its thinner cord suits.
- Sea to Summit - Sells finished guy cord sets with integrated adjusters and quick-connect toggles, sized to its own Alto and Telos tents.
- MSR - Publishes excellent detail on its stakes and shelters, and unusually little on its reflective cord kit.
How to read a listing without getting fooled
Work out first whether you are looking at cord or a kit, because the pages are written differently. For cord, find the diameter and the weight per length, and treat both as required: a cord with no diameter cannot be matched to adjusters and cannot be compared to anything else. Then look at how the reflectivity is achieved and whether the construction is described, since a named jacket and core tell you the maker has something to say. For a finished kit, find the lengths and count them against your shelter's guy-out points, and check what the connector needs at the tent end. In either case, read for a sentence where the maker limits its own product, because the ones that tell you where a cord does not work are the ones being straight with you about where it does.
How much should you spend?
Cord is cheap and the total is not. Budget buys a basic reflective cord or a small kit, which is fine for replacing a lost line. The mid-range is where cord with a published diameter, a named jacket and a stated weight per length lives, and where most people should buy. Premium is either an ultralight fibre such as Dyneema, bought for a weight saving measured in tens of grams, or a finished set where you are paying for the toggles and adjusters as much as the cord. Whichever you choose, price the hardware in: a hank of cord and eight linelocs costs meaningfully more than the hank alone, and that is the comparison against a finished kit rather than cord against cord.
Questions, answered
Can I use paracord for guy lines?
You can, and it is a common first answer, but it stretches. Paracord is nylon and designed to absorb shock, which is the opposite of what a guy line wants: it goes slack as it takes up moisture and temperature change, so you wake to a sagging fly. It is also heavy for the job. For a shelter, a low-stretch polyester or Dyneema cord holds tension far better.
How do I stop cut ends fraying?
Melt them. A lighter briefly touched to the end of a synthetic cord fuses the fibres, and rolling the softened end between wet fingers gives a neat finish. Do it as soon as you cut, because a frayed end will not pass through a lineloc cleanly and gets worse every time you use it.
Should guy lines be tight or slack?
Firm rather than banjo tight. A guy line pulled to its limit puts all the load on the stake and the fabric with nothing left to absorb a gust, which is how stakes pull and seams tear. Tension until the fabric panel is smooth and the line is straight, then leave it. Expect to retension after rain, which is when an adjuster earns its money.
Do I need different cord for a tarp than a tent?
Usually more of it rather than different cord. A tarp needs longer runs to reach anchors and has more guy-out points in use at once, which is an argument for buying by the hank in 2mm rather than a fixed-length set. The same cord that guys a tent works fine on a tarp; you just need several metres more of it.
Or jump to the head-to-head: Lawson Equipment Reflective Glowire Cord vs Zpacks Z-Line Reflective Cord, 1.3mm.
