Zpacks Duplex Ultralight Tent for PCT thru hike

William, I’ve seen a lot of conflicting and anecdotal evidence about the construction but can’t find anything substantial. You may be (or probably are) right that the mylar is the same thickness though that would seem to refute Dyneema’s own claim that .74 (CT8 is the new name) is more abrasion resistant. Weird.
Either way, I edited my previous post.

From Zpacks website:

Link http://www.zpacks.com/shelter/duplex.shtml

(Nick alluded to earlier)

“The expected life span of this shelter is at least one full 2500+ mile thru hike, or many years of casual use with some care.”

.51 oz/sqyd Standard Cuben Fiber Fabric
The default material choice on this tent is .51 oz/sqyd Cuben Fiber. It has high tensile strength and can handle strong winds, storms, and all the typical conditions a tent will be in. This is the weight I used on all my long distance hikes, and I’ve never had a problem with it becoming damaged. If it ever were to get punctured or torn, I know that I can fix it easily in the field with Cuben Fiber Repair Tape.  A piece of matching repair tape is included with the tent.

The floor material on our tents is always thicker more puncture and abrasion resistant 1.0 oz/sqyd Cuben Fiber regardless of which tarp material you pick.”

“.67 oz/sqyd Camo Cuben Fiber Fabric
This material has the same Dyneema thread count as standard .51 oz/sqyd, but with a slightly thicker laminate with a Camo pattern on it. The Camo print brings the fabric weight to .67 oz/sqyd.

It blends in to nature well. It is darker, less transparent and offers more privacy. Cuben Fiber has a bit of a sheen to it when it is new, but it dulls down significantly with some use.

This video by John Abela shows the Opacity and Color of Camo Cuben Fiber.

This material is more expensive. It adds around 1.5 ounces (45 grams) to the weight of a Duplex.”
“74 oz/sqyd Spruce Green Cuben Fiber Material
This material has a higher Dyneema thread count which gives it a higher tear strength. The standard material is already difficult to tear, so in our opinion this weight is unnecessary. Some people like it for added peace of mind.

It is also a bit thicker and darker than the standard weight. It is less transparent and offers more privacy, but it is not as dark as camo.

It adds around 2.2 ounces (62 grams) to the weight of a Duplex”

There isn’t a controversy.  The OP asked for recommendations for a material choice and we’re giving recommendations based on our experiences.

I see (and quoted above) their description of the fabric choices but I don’t see the cost increase.  Let’s just say it’s an extra $60 or 10% the cost of the shelter.  Is it going to give you >10% added life expectancy?  Not enough reliable data to say.

Zpacks says that their 1oz cuben fiber is more abrasion resistant, so it stands to reason that the .74 is more resistant than .51.  For the most part, the only abrasion the tarp portion will need to deal with is the friction of packing and unpacking the shelter, and any branches that may come in contact with the shelter during a windstorm.

As other BPLers can attest, we received some epic wind and rain at this years PNWGGG.  There were at least two duplexes there (one .51 & one camo), and I was in a hammock under a Zpacks .51 tarp.  My tarp was getting hit broadside by some serious gusts.  I won’t try and guess the wind speed but it was enough to pull my guy lines through the line locks, rip stakes out of the ground, and convince me a couple times that I was getting hit by a freight train.  YMMV.

I was in a .51 Tarp there and blew a peg too.   I feel it is reasonably tough provided you dont have it scraping on a branch or something, which  I would never do anyway, no matter the textile.

My only degradation concern is from the fat ol’ sun and its band of rays

BTW, .51 and .74 are not the same; you must be thinking of the camo stuff that’s the same thread count as .51 with the patterned layer sandwiched in. .74 uses both thicker membranes (edit: maybe? Not sure about mylar being thicker) and a higher thread count so it is both stronger to sheer forces as well as being more puncture resistant.

The full name for 0.5oz cuben is CT1K.08 or CT1E.08.

CT = Cubic Tech (manufacturer)
1 = amount of spectra strands
K or E = type of spectra strands
.08 = thickness of mylar used.

For a long time 0.5oz cuben was CT1K.08 but apparently they updated the strand type at some point so it’s now usually called CT1K.08. Either way it has 0.08 mylar.

Now 0.7oz cuben is the exact same stuff but with double the # of spectra strands (1K vs 2K). So it’s CT2K.08 or CT2E.08. There’s the same mylar and same bonding process, so if you agree that cuben usually meets it’s demise from mylar degradation, then there’s no difference between 0.5 and 0.7oz.

The 1oz and heavier cubens use thicker .18 mylar.
1oz = CT2K.18
1.5oz = CT5K.18

Hey Dan, way to perfectly illustrate the use of the Slippery Slope argument! OP asked for opinions on .74 vs .51 for their Duplex specifically, not for an argument to make all the items they carry heavier.

Indeed they did, but you provided (in part) a rationale that isn’t specific to 0.5 vs 0.7oz cuben, but rather could be used to justify any form weight gain (“go for item A over B, because you won’t notice the extra X ounces on the trail). I pointed out that this is a generic rationale and a problematic way to make decisions, because this rationale appears on almost every gear decision thread.

In fairness, you also presented other reasons for the 0.7oz (e.g. tent failure is much more problematic than other forms of gear failure) which are valid and relevant to the OP’s question. I agree with this thinking, but do think the underlying assumption that 0.7oz is more durable needs to be seriously questioned. It is stronger under extreme loads, but for abrasion I don’t see how it can be since the mylar is the same, and the mylar peeling away from the rest of the sandwich is the most frequent problem in my experience.

Zpacks says that their 1oz cuben fiber is more abrasion resistant, so it stands to reason that the .74 is more resistant than .51. For the most part, the only abrasion the tarp portion will need to deal with is the friction of packing and unpacking the shelter, and any branches that may come in contact with the shelter during a windstorm.

As described above, I think this is an incorrect interpolation. 1oz cuben is more abrasion resistant because it has the 120% thicker .18 mylar, which 0.74 cuben lacks.

While tarps do experience very little abrasion, they are subject to something related. The mylar of cuben tends to peel/bubble/crack from abrasion, but also from torsional stress. Take a cuben roll top sack for example. If you crank that down quite a few rolls and do that for 100 nights, the cuben will be utterly destroyed at the roll top. The twisting strain at the roll top causes the mylar to bubble/peel apart from the rest of the sandwich and then there’s fuzz everywhere. I’ve stopped using cuben dry sacks after going through several for this reason. Tarps don’t get it anywhere near this bad, but the stress that comes from being folded/stuffed, and also from wind forces over time, does eventually cause the cuben to delaminate irregardless of how much spectra is inside.

My conclusion is that 0.5oz cuben has enough spectra to be plenty strong for any forces reasonably encountered in the woods, and it’s eventual demise will come from reasons unrelated to the amount of spectra. If you might be in extreme conditions (like Mark) then go for silnylon.

“You may be (or probably are) right that the mylar is the same thickness though that would seem to refute Dyneema’s own claim that .74 (CT8 is the new name) is more abrasion resistant. Weird.”

Dyneema may be correct, even if the mylar thicknesses are the same. In another thread on here, someone gave a convincing reason why the increased thread in .74 would add to the abrasion resistance. Unfortunately, I remember neither the thread nor the reason.

BTW, I have 80 or so nights in Duplex in .51 cuben, and I would have no qualms taking it on the PCT from what I’ve read about the walk.

Dan, You sort of got what I was saying but in the wrong order of importance. I didn’t provide a rationale to justify heavier things, I said the benefits of .74 are their own justification then acknowledging we are only talking about 2oz, not 8 oz or something which would counter any benefit to the point of being worthless. I certainly see the validity of your point about not taking that too far but it’s probably better left as a stand alone discussion.

I think the major disconnect is where we are all starting from. Based on my experience I side with SMD, MLD, Yama, and HMG that .74 is the “standard” and if you choose to go .51 you are giving up some durability for those couple ounces. Many of you are siding with Zpacks that .51 is the standard and going to .74 is adding unnecessary weight. Do you cut off your toothbrush handles? .74. Do you not even bring a toothbrush? .51 :)

I believe Steve Evans had a .33 tarp years ago… I wonder how that’s held up

For almost 5 years I used a .3xx (or whatever it is) Hexamid on almost every trip — well I carried it, but only set it up when the weather was bad. Given that, it was set up many times each year. It is still in good condition. I switched to a larger CF shelter a couple years ago. To be honest, I don’t know much about the different iterations of CF and bought both of these CF shelters without regard to thickness.

The .33 stuff is kinda neat. If cost was no object, I’d use one as a tarp in non-extreme conditions. The lower spectra count seems to make it easier to puncture, and for those punctures to extend, but for normally encountered tarp forces it seems okay. I used a .33 sack for my clothes for a couple years and it lasted okay – eventually failing when the mylar peeled off (no surprise).

.33 cuben is CT0.5K.08, so same mylar but half the spectra strands of the 0.5oz stuff, and 1/4 as many compared to the 0.7oz stuff.

I used a hexamid solplex .51 for a CDT thru in 2013 and still use it. Looks almost new.

Here’s a hairball for you guys.

Done 700 miles of the PCT plus bicycle trekking with my Camo Duplex

First of all invest in some good quality tent pegs. The Duplex is a bitch to setup in sand without rocking every stake but then what tent isn’t. The desert is a test for any tent. One thing about Cuben fiber is that the tear strength is 4-5 times that of Sil Nylon so there is the most important benefit for it’s use in a single wall tent.

The learning curve for good set up is longer for the Duplex and the external poles really help gt a taunt pitch or a crash and burn pitch with no stakes. They weigh 10 ounces but I think they are worth the weight. Combined with hiking poles and stakes with both vestibules staked out plus rocks you have a strong shelter that will resist shredding as well as anything.

Even with the external poles you still have to stake it down (wind!), and in reality it remains only semi-freestanding because the vestibules must be staked out regardless of whether you pin the corners.

Personally, I’m not going to carry an extra 10oz because I’ve had enough experience pitching it only with trekking poles that getting a good, taut pitch quickly has become a non-issue. I realize that cyclists don’t typically carry trekking poles, but I think that for  cyclotouring I would make myself a pair of collapsible poles from 10mm or 11mm carbon fiber tubes that would be plenty strong.

The problem where I usually hike is not staking the tent in sand but in rocky duff and soil, and this is the primary factor that determines speed of setup. Many, many times I’ve backed up stakes with rocks…

Videos of tents being erected in two minutes on a manicured lawn in benign weather are a bit misleading to the average bloke who hasn’t got a fair amount of backcountry experience.

Hey Bob,

Thanks for the intelligent response on the Duplex. Everything you say is true.

Especially the set up videos put out by the company.

The Duplex is not for amateurs or posers.

Just let me add that if you do invest in the external poles, 10 ounces or not , you will be carrying them because they are just so nice and in a howler they cut the flap and pop and snap. You sleep quiet.

I just carry 10 ounces less of water in my pack, what is that…a big drink.

And we all have luxuries don’t we? Half a book, pillow and poles, spare gas canister, Milky Ways, fulll length Thermarest neoair x-lite. Oh the sin.

If I was paring back the poles would be the last to go.

All hail the Duplex.

B-3

All hail the Duplex.

LOL, well I’ll have to agree with that… I understand that we Duplex aficionados sound like a brain-washed gaggle of One-Note-Sallys, but darn if it doesn’t check every box for an awful lot of people.

How true, BTW is see Westchester County in your locale. Did some high school at Briarcliff Manor.

We were snots at 14 in 1959. We camped on the Rockefeller’s estate(in Pleasantville?) with a bottle of Scotch and orange juice. This was before it was partly public.

https://parks.ny.gov/parks/59/details.aspx

Things got out of control and so did the fire. It burned down to a small creek so we were saved. We retreated drunk and blackened to higher ground but our sleeping bags which we used as fire beaters were done for.

We never got caught. We were using shelter-haves for tents for those who know what they are. That’s a long way from a Duplex.

One of many long nights at camp. And I can’t stand the smell of Scotch.

B-3