Backpack problems, and answers

In the last few months I’ve had impetus from several directions to hit the reset button on backpacks as completely as possible.  Shake off and re-examine as many assumptions as possible before I put them into practice.  This bag, and this post, are only a first step towards that end.

Problem 1: Seams are the enemy.

Seams create weak points and add weight, bulk, and (potentially) complication.  Testing has confirmed my years-old assumption that burly fabrics will rip stitches, while weaker fabrics will rip from stitch hole to stitch hole.  Tuning thread to suit the fabric and reinforcing seams can mitigate but not do away with these issues.  The complication is that bag shaping is a vital factor in making a pack which carries, wears, and uses well.  For the bag below I went back to the roots of the 610 pack and copied my original design as closely as possible.  It sure carries well, and after a few years of love affairs with zippers its not so bad to have a simple top loader that demands some thought in packing, and doesn’t mind sand (this last highly relevant in the desert, and much less so in NW Montana).  It would be possible to make this design with fewer inches of seam overall, but only by adding significantly to the complication and construction difficultly.  Vertical seams are simple, easy to reinforce and if you eschew binding tape in favor of big seam allowances which can be folded and top stitched, pretty darn resistant.  A bag this tall and skinny is a specialist tool for ultralight mountain backpackers and canyon hikers, and really not the most versatile design.

Larger bags, with suitable compression, are more open to compromise.


Problem 2: Lightweight fabrics which are durable enough for real world longevity.

I’ve written far too often and in many places that lightweight fabrics are not the most efficient way to make a light backpack, and with decently spare designs hardly ever having more than 2 yards once everything is added up (reinforcements, belt, harness, etc) this is true.  But weight is still weight and pack fabrics remain one of the more common areas where fat could be rendered.  This post has been one of my most read, ever, since I published it over three years ago, and while the specific options have expanded, the landscape has not much changed.  And probably won’t until someone starts using woven dyneema in a way where they aren’t obliged to upcharge the hell out of it.  (One wonders if HMG changed their whole 4400 line to woven what the net effect would be on price, over 3 years.)  For my own use, the varieties of 210 denier D-P laminate remain the point where fabric is too light.  I made the body of my fatbike framebag, usually a fairly low impact area, out of X21RC, and the damn thing has a little hole after less than a month.  From what, I could not say.  This is evidence of a divide which will always exist in the different types of durability different people demand; X21 does fine in all but the nastiest brush, but get it close to pointy rocks at it wilts like a rose hit with Fluroxypyr.

The pack pictured here is make mainly from a prototype fabric (the coyote tan stuff), which is a 330 denier Cordura with a very thick PET laminate.  The company in question called me last spring and asked for my thoughts on the ideal pack fabric.  In summary, my feedback was to make X33 without the X-ply, perhaps a thicker film, no backer, and in a nice lighter earth tone.  They delivered, and M and I happily used packs made from it all last summer (seen in action here among other places).  It remains the best pack fabric I’ve used.  I now possess all of what remains from the test run, and am putting it to use very sparingly.  Said company is looking for a party interested enough to invest in a larger production run, and if any reader fits that description, they should email me so I can set up a conversation that might put more of this stuff out into the world.

The reinforcement patches shown are plain PU coated 330 denier Cordura, in a lovely dark dark green that photos poorly put sets off the coyote nicely in natural light.  Laminate fabrics (D-P and hybrid cuben, essentially) have many virtues when used in backpacks, but aren’t the holy grail.  Truly good PU coatings come close when it comes to waterproofing, and hardly anyone is in a position to really comment on how the heavier laminate fabrics will stack up in terms of delamination.  Probably not a pragmatic concern for many, but if light hybrid cuben can start to delam in under a year of heavy use, one has to assume the burly stuff will eventually.  The nice thing for the moment is that the relative scarcity of laminate fabrics and their place as a premium product has kept quality high.  Trying to source good PU Cordura in small batches is a roll of the dice, whereas one can buy X33 or X50 and know all aspects are top shelf.

The reason for the reinforcement patches on the base and sides of this pack are to experiment with how light a fabric will stand up to hard canyon use.  I shredded a simple X51 bag in about 7 total hours of use doing this back in December, and the numerous were all exclusively due to harder things (rope, waterbottle, full drybag) pressing from the inside.  Theses reinforcement patches are 1/4″ bigger than the main body panels, which will hopefully deflect pressure and allow the fabric to perform closer to its potential.

Problem 3: Enough suspension, but not too much.

At this point, any time I have a hipbelt on a backpack I want some form of rigidish (read, metal) suspension, well anchored.  There are acute limits to just chucking a center stay in, but there are also very substantive benefits, and not that severe a weight penalty.  I was genuinely shocked two weekends ago to see just how vague the connection between the stays and harness elements of the HMG 4400 packs are, testament I deem to how low the bar is in this department.  The trick isn’t just to make a decently stiff without having to add too much weight in the form of supporting and connecting elements, it is to build the proper amount of play into that frame (which is probably why the HMG system is so beloved).  There are plenty of options available for massive loads, and some decent ones for light loads, but it seems to me that the middle ground of 30-50 pounds still needs attention.

Carbon will remain problematic until a company can invest in proper molds and manufacturing which can produce a contoured product that won’t break.  Stone Glacier and Zpacks have, in very different directions, taken straight carbon as far as it can go.  That the former is adding 6 ounces to the stays alone just to achieve a modicum of curve should tell us something about the limitations of a straight frame.

For this pack, I put on thick shoulder straps, an external pad sleeve, and inside the sleeve loops to attach a webbing hipbelt.  90% of the time I won’t use a belt, but it is a good option, and a removable pad adds just the right amount of structure.


Problem 4: Closures

I have a profoundly mixed relationship with roll tops.  On the one hand they’re clean, weatherproof, provide vertical compression without extra straps, and are the easiest closure to sew (one of the reasons they’re so popular).  On the other, they’re fiddly and require buckles, which are the next enemy after seams, and a more intractable one.  I tried a drawcord and top strap on this one, and am not sure I like it.  In theory it’s faster and allows for overflow capacity, but I’m not sure that theory holds water any more.  There is a large extent to which chasing “easy” closures and quick access ends up being a half-assed solution for organization on the part of the user.

Problem 5: Side pockets

Side pockets on packs are a horrid nuisance.  Slapping on a flat panel of stretch fabric is the simplest solution, and one which actually works pretty well until they get shredded.  Fabric pockets are tougher, and if abrasion against rocks is not much of a concern making them huge and putting them all the way against the bottom seam should guarantee good access and plenty of capacity.  My problem is that I don’t always want side pockets.  In canyons they get destroyed, and they interfere with the placement of compression straps, and the attachment of things such as skis.  Is there a way to make them modular while not sucking?  That is the next project.

13 responses to “Backpack problems, and answers”

  1. I love reading your analysis on pack components and fabrics. Like yourself (although with significantly less experience) I’m enamored with backpacks, so a glimpse into your mind is always educational. Thanks for the quality posts!

    1. Much appreciated. And as an “amateur” don’t count yourself down too far, plenty of folks in the industry who never get beyond a two hour radius of their house, which goes a long ways toward explaining the often baffling designs we see.

  2. If the undisclosed party makes the 330 laminate without the x ply I will buy several yards. Along those lines I saw on BPL ripstop by the roll will soon stock the woven non woven dyneema laminate HMG inter alia use. I am waiting on a real world abrasion comparison to xpac, cost (which I haven’t seen from RBTR) vs value, etc before I would jump to buy that though.

    1. I’ve heard 200 denier with a PU coating. Should be good and on the cheaper side, though still 30 or more a yard. Abrasion resistance should be excellent.

  3. Hi Dave,

    Your blog is a gold mine. I’m building myself a do-it-all climbing pack that will occasionally see heavy loads, and I’m curious about some of your suspension choices. You seem to think very highly of the floating hip belt attachment that the paradox packs use, and you created a dual stay floating hip belt attachment for the frame you built for the stone glacier solo pack. Why not go with a floating hip belt attachment for the smaller 610 packs too?

    My guess is that at heavier weights the floating hip belt is more comfortable, with less chance of the stays exerting pressure on the lumbar area. At lower weights, is it that the hip belt sleeves just provide a more stable connection to the pack? I do the occasional 5th class move with a heavy pack, and my concern is that the floating hip belt will allow too much play into the system, causing the pack to sway and throw me off balance. Though, I did see you mentioned in another post that the Unaweep performs well in 4th class terrain. What do you think?

    Thanks for the resource.

    1. A floating belt can provide a less close connection. I need to experiment more with one for smallish packs and sub 25 lb loads. Another issue is that slimmer folks need a narrower connection with a hanging belt which can exacerbate tipping issues.

      Watch this space. 🤗

    2. Justin; to give you a most exhaustive answer now that I’m back home and not on my phone with dodgy wifi…

      There is inherent potential in a floating belt system to introduce more sideways play. There is also inherent potential for this system to ride closer to the back than any lumbar pad system. Be nice to have both, but as you mention at higher weights the stay-pressure issue becomes significant.

      I’m beginning to think that the 12″ center to center measurement that SO uses for their hanging belt is too wide even for me. This based on using the belt on the kid carrier, which doesn’t have the below advantages of fit and frame height. On the Unaweep system the 12″ spacing doesn’t create stability issues for me, but that is because the stock frame curve fits me so well, and because I always have a decent bit of weight on my shoulders. Others have reported different results. Would a 10 or 9″ c-to-c arrangement, with stabilizer straps, work well? Based on photos I assume McHale uses something like this figure on their hanging belts (which is where I believe Nathan C. got the idea for use with Paradox Packs).

      Hanging belts also have to hang, which necessitates the frame and bag being lower on the user than a lumbar system. Not ideal for technical climbing, not really a big deal for general mountaineering or canyon stuff where one isn’t doing pitch after pitch wearing both pack and harness.

      Again, mulling ideas about how to have both in one, but very very early in terms of experimentation.

      Thanks for reading and asking good questions. I get lots of benefit out of having to clarify such distinctions.

      1. Thanks for the insights Dave.

        It would definitely be great to have both comfort and stability. I’m going to go with something exactly like you mention. I’m a pretty skinny guy myself, but I’ll try out the 10″ spacing. Seems like it might be a good compromise between stability and wrap. In order to further address stability, the hip belt padding will go over a webbing hip belt, similar to what you find on the Patagonia Ascensionist 40L. My goal is for the webbing hip belt to assume the role of stabilizer straps.

        I’ll give you an update letting you know how it worked out. :)

        1. Sounds good Justin. Thanks, and good luck.

        2. Are you guys aware of Edward Abbey’s take on the Seek Outside suspension? It’s designed to be lighter, more flexible, and more suitable for canyoneering and scrambling. He says it carries extremely well in the 20-40 lb range that Dave is discussing.

          He argues that you can offset the weight of the bottom cross strut by omitting the lumbar pad and belt stiffening you would need for conventional internal stays.

          Like you, I’m playing around with ideas for a mid-load pack (7 days food on cold alpine walks) with an external U frame, and thought I would use Edward’s approach as a starting point.

        3. Geoff, Brendan’s pack is a good example. Simple from a fabrication perspective, and effective.

          I’ve put a lot of time and prototypes over the past 18 months into solving the two problems I mentioned in my April 2nd comment. The support point spacing issue is real, and good results can be had by narrowing it, but there are lots of moving parts in doing so. If you use two stays, some sort of horizontal support is required to maintain spacing under load. You can use plastic and foam to accomplish this; it won’t save much weight over a stay, but can result in gains in form factor. Ride height is actually a less flexible problem, as the attachment point has to ride a bit below the bottom of the belt, but this is really only an issue for climbing-type applications.

          More specifics soon.

  4. If you’re interested, I have modular pockets that Chris Zimmer made for my Porter. Let me know if you want to see them or hear any thoughts on how they could be improved.

    They are, of course, a trade-off. It’s nice to be able to remove them, but without being fully sewn in, they move in a way that ever so slightly throws the pack off. As I said, I think they could be improved, but at what cost?

    1. I do remember those. As you say I’m not sure that tradeoff can be successfully negotiated, but I aim to try.

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