Hybrid Cuben Durability – What’s the truth?

Per their websites, Zpacks is using a 2.92oz/yd hybrid DCF while HMG’s white packs are 3.4oz/yd – yet both say they are 50D polyester. Zpacks says their inner DCF is 1.43oz/DCF, so maybe HMG is using a heavier variant of inner DCF? Seems a bit unlikely since 1.43oz is already the tough .18 mylar and about as much dyneema as you can get (5K).

Anyways, in most instances it’s the outer face fabric that limits durability, so I think these fabrics will hold up the same to most durability tests since they use the same 50 poly. When you have sharp branches stabbing your pack or it slides over rough rock, that’s when you test the outer face.

I don’t think 50D polyester is a very durable face fabric. There’s no magic here – it’s 50D polyester which is a really light material. Consider that a lot of cheap, car camping tents use 50D poly for the fly and 70D poly for the floor. I’ve owned several packs with hybrid DCF, and I usually damage it pretty quick bushwacking. I had a custom hybrid DCF pack from ULA and on my first true bushwack (10  miles) I put a 6″ rip in it from a stick stabbing it, and in another spot scraped the 50D poly off the underlying DCF. If you’re really bushwacking (as opposed to meandering off-trail through alpine meadows), then even 210D fabrics are relatively easy to damage.

I think what’s happening here is that you’ve got a lot of really lightweight / SUL hikers that are saying this stuff is beefy because they’re comparing it to the even lighter materials they are used to, and they’re not really subjecting it to much abuse (which is good). It does hold up fine for most backpacking where you’re primarily on-trail. It’s entirely possible to walk 2600 miles on the PCT and not really put that much wear on your pack. I’ve beat up packs way more in a single day than I did on the entire PCT combined. So you see a lot of folks saying “so bomber – I used it for PCT + CDT”, and it is close to bomber in that context (light loads on good trail), but it’s far from bomber in tougher applications.

So my opinion is that it’s a fairly light but still reasonable fabric for normal hiking, but shouldn’t be construed as a good choice for bushwacking. In more detail compared to some other fabrics:

2.9/3.4oz Hybrid DCF: Okay on trail, Inappropriate for bushwacking
Xpac VX07: Same
XPac VX21: Bomber on trail, okay bushwacking
XPac VX42: Overkill on trail, close to bomber bushwacking, okay canyoneering.

With regards to the different consensus for Zpacks for HMG packs, I think a lot of this is coming from the different frame designs. I’m no expert on Zpack’s frame, but I’ve spoken to a lot of owners where the frame has rubbed through the hybrid DCF, so the frame is subjecting the material to a higher level of wear than HMG packs and thus failure happens more easily.

^^^

Well said.  Thank you.

Buy a pack made of full Dyneema or Spectra and it will outlast you :-)

I bought one of the first zPacks Zeros and it lasted 6 years of a lot of use. I was careful not to drag it across boulders and such. In the end the material just started to delaminate in many spots. So I has happy with the product and it lasted longer that I had anticipated. This is going to be key with any kind of gear — not to abuse it. So if one hikes where a pack will be subject to abrasion or pointed shrubs it might be better to get a pack that can withstand this environment — or be willing to buy a new pack every couple of years.

I bought my last pack 6 or 7 years ago and now have two go-to packs. Both are made from durable materials and I’ll never need to buy another pack in my lifetime. Another benefit is I almost never read pack reviews, which adds more coins into my timebank inventory.

I have a few white HMG packs (50d face fabric) and also a few black HMG packs (150d face fabric). I have taken both on insane cross-island bushwhacks here in Kodiak (swimming for miles and miles through thick alder and salmonberry on steep mountainsides) and have yet to tear a hole in either fabric thanks to the brush. I have put holes in them, but that was from an ice ax or ski edge. So mostly cuts, not abrasion. Not a ton of rock contact here.

What does break down is the bond between the cuben layer and the polyester face fabric. This is noticeably worse in the heavier black 150d hybrid than in the lighter white 50d. I wonder if the stiffer and thicker face fabric puts more stress on this polyester/cuben interface. My black HMG packs look like crap where you roll the top down and the fabric sees the most mechanical work. The face fabric is all puckered and scrunched, the cuben on the inside delaminating with wispy threads of spectra all over. I have beat up my white packs worse than the black ones, and they actually seem to be holding up better. The process of delaminating damages the inner cuben. I don’t see any benefit in durability from the heavier fabric. In fact, the opposite seems to be true for my use.

Jameson, you might be interested in the BPL podcast about DCF if you haven’t listened to it already.

“What does break down is the bond between the cuben layer and the polyester face fabric. This is noticeably worse in the heavier black 150d hybrid than in the lighter white 50d.”

Maybe it’s that with higher d (thicker threads) they are also further apart, so it’s easier to delaminate.  With smaller d, closer together, adjacent threads better take the load so it doesn’t delaminate as bad

Same thing with PU waterproofing.  The PU layer sticks to the threads better when they’re closer together (smaller d).  Or there are bigger holes between threads.

Some good information here already. I’ll add my experience from mostly using packs off trail in the Sierra, often dragging packs against granite. I’m not particularly careful with my packs….

XPAC 42 – failed after two trips – at least two holes and other significant scuffing.

Cordura (210D?, perhaps 500D?) – this is an ancient North Face pack that I’ve abused
for many years (18+) and over many trips. It’s held up remarkably well after many rocky off-trail trips.

What makes things worse is the bear canister in the pack unless you’re careful to wrap the canister with a thin pad or clothes. The pack material gets between the canister edges and the rock which is terrible on XPAC – a rather rigid material. Cordura is softer so sees much less abrasion.

In my experience and for my use – nothing comes close to Cordura…..

XPAC is completely waterproof and lighter than Cordura but nowhere near as durable.

I have owned an HMG pack that I didn’t like much at all and sold it. I don’t think the hybrid cuben would hold up to granite. I also tried an early Zpacks pack – I returned it as I felt like it was too delicate for my use.

The answer depends on your intended use and how careful you are with your gear.

Not a fabric expert, but I might suspect the color and subsequent heat absorption on the black packs for causing the de-lamination.  When I first head about the HMG packs, I figured they didn’t have a choice on colors, or they were going for the James-Bondi-blend-in-with-snow thing.  When I decided to buy a Windrider, I picked the white specifically to keep the pack and contents cooler, otherwise I would have picked the (presumably) more durable 150D.

“XPAC is completely waterproof and lighter than Cordura but nowhere near as durable.”

For the same weight of face fabric (e.g 210D vs 210D), X-Pac is heavier because both have a nylon face fabric but then X-Pac adds several layers inside of that which adds about 50% to the weight (X-Ply, 0.25mm PET, 50D polyester typically, but it varies as they make many versions).

If you compare the same weight of X-Pac (e.g. VX21) and Cordura, you’d expect their performance to be pretty similar because they are both the same weight of nylon, and I think they are both even nylon 6,6. So almost exactly the same molecularly. However there is more to it than just this – there is also the tightness of the weave, calendaring and probably some other factors. Calendaring (or lightly melting the material) does increase abrasion resistance quite a bit because it slides through the brush better. The 50D polyester used in hybrid cuben does subjectively appear quite heavily calendared, which I think is why it slips through brush pretty well for it’s weight. But once you catch it, then it rips fairly easily in my experience. Back on X-Pac though, it’s hard to paint X-Pac with a broad brush because there are so many variants, but X-Pac also offers calendared face fabrics that likely perform much closer to Cordura nylons. They’re just shinier (see the products from Revelate Designs) so most manufacturers prefer the duller, non-calendared X-Pac.

“I might suspect the color and subsequent heat absorption on the black packs for causing the de-lamination.”
Interesting theory. I just don’t like black because my cheese and chocolate always melt. I certainly agree there is a temperature difference, so it could be a contributor here.

To clarify, when I say X-Pac, I mean the fabric used by Seekoutside and similar vendors.
The VX42 (and I’m guessing the VX21) used in those packs is particularly susceptible to abrasion.

I’m speaking from personal experience with such packs which did suffer abrasion after just a couple of trips.

I’ve used a Cordura pack (500D?) for almost two decades in similar settings and similar abuse. No tears at all – except the mesh side pockets were shredded and have been repaired twice – at no charge by North Face after 12 years of owning the pack.
The packbag itself has held up amazingly well.

FWIW, DP abrasion tests their X-Pac fabrics using the ASTM 3884 test. Their results are:

VX07 – 500 cycles
VX21 – 900 cycles
VX42 – 1700 cycles

Different treatments to the fabric do make a big difference. For example, there LiteSkin LS07 is rated at 2000 cycles despite along being a non-woven 70D because there is some fancy stuff going on.

I’m not sure what the Cordura ratings are, but they probably are higher.