Backpack articulation/freedom of movement

[Stumphges]

I’m considering buying a Seek Outside Divide. The capacity (load and volume), waterproof and durable fabric, ventilation, suitability for wide range of trips (one pack fits all?) and “articulated” suspension are all big attractions for me.

But how “articulated” is that suspension, really? How does it compare with the internal frame packs that allow for the greatest freedom of hip and shoulder motion? What do you consider the best pack in this area? I’m particularly interested in free oppositional pelvic and shoulder girdle rotation (right hip goes forward as left shoulder pulls back, etc.) during walking.

I know opinions vary on this subject and I’m interested in all of them.

[Roger Caffin]

My external frame packs don’t have any articulation – if I understand what the term means.

Cheers

[Michael Sirofchuck]

I have both the Seek Outside Unaweep and Paradox Evolution packs/frames.  They fit and hike as well or better than any external frame pack I’ve used.  I don’t know about the articulation of which you speak.

[James holden]

zilch …

any good climbing or mountaineering pack would have more mobility …

but then again the divide and its brethren were not designed with such activities in mind …

if you want mobility then a climbing pack, or a pack based on such a design is what you want

you generally dont want is external frames, or things with air gaps against the back

;)

[Brad Rogers]

The Seek Outside frame is a U shape so it is open at the top and its two peices so each arm of the “U” can articulate independently if that makes any sense.  It’s not your daddies external frame.

[Stumphges]

Thanks, everyone, for your responses.

Roger,

Seek Outside call it a “articulating load responsive frame.” https://seekoutside.com/evolution-suspension-only/

As Brad describes, above, the frame is an inverted U and there is a joint allowing rotation about an axis in the coronal plane that passes through the very bottom of the U. This jointed U is the “articulated” component. This articulation allows the two sides of the U to rotate about that axis fore and aft, freeing the shoulders to rotate in opposition to the hips. The joint is a simple one, though, and allows less motion the more you load it, which might be desirable with greater loads. I think that is the “load responsive” part.

The fore and aft movement of the U’s uprights, though, take them out of the plane of the spine, and in opposition to its normal side-bending during gait, so I suspect there is play elsewhere in the system to make it all work. But I don’t know and I guess that’s one of the reasons I’m asking.

Eric,

I’ve primarily used an old 36L climbing pack for backpacking, bought shortly after reading Jardine many years ago. (It was the lightest pack I could get at the local outfitter.) But it’s a simple one without a true hip belt. This was OK before my wife started coming along and shelters and meals got fancier, etc.

One interesting thing is that the literature shows that a true hip belt allows more rotation of the pelvis during walking than a pack suspended only from shoulder straps. I would be using a Divide primarily for trails, not mountaineering, but I would like the best combination of load bearing and mobility, plus ventilation, possible. My hips and low back have gotten a little dodgy over the years and my reading has convinced me that load bearing on the pelvis that also allows free movement of the pelvis and rotation of the shoulder girdle is ideal.

Michael,

How do the Seek Outside packs compare to internal frame packs you’ve used?

Do you notice them to be more flexible, or allow easier movement off-trail, for example. than other externals you’ve used?

 

[Roger Caffin]

Seek Outside call it a “articulating load responsive frame.”
Marketing spin.

Cheers

[James holden]

stump …

heres a simple example  …

doing this excercise …

my divide does pretty poorly compared to all my other packs …

i have a TNF terra nova internal frame, an osprey mutant with a solid plywood frame i use, and various frameless packs with plastic stiffiners …

part of the issue is the GAP between the frame supports on the divide … the wider the gap the more torsional resistance you will have generally …

despite my mutant having a solid one piece plywood frame its much more mobile than the divide because (as a smaller pack) its narrower and the frame is narrower ….

my TNF 65L is as well due to the narrower frame gap

now whether you need to touch your toes windmill style while hiking is another question …

but you did ask about torsional mobility !!!

;)

[Pigeon]

Would a single vertical stay be best?

[Stumphges]

Roger,

Thanks for nudging me away from the baby seal’s fate.

Hey Eric,

Many thanks. Good info. It sounds like Seek Outside’s new lighter pack will have a narrower base.

Any mobile and torsionally flexible frame with good ventilation that you’re aware of? (If I can’t get the great load bearing, I’ll focus on the the other two parameters:)

I’m curious about the Flex Capacitor. It’s “Y” shaped stay suggests torsional flexibility but the reviews have focused on its load bearing capability.

[Stumphges]

DC, yeah, I’ve read that. The word is that a single stay is good for flexibility but not so hot for load-bearing because all of is concentrated at the center of the belt.

This style seems to work on the Exped Lightning and Flex Capacitor, according to reports.

[Bob Moulder]

Any mobile and torsionally flexible frame with good ventilation that you’re aware of? (If I can’t get the great load bearing, I’ll focus on the the other two parameters:)

Zpacks Arc Blast has all that at 21oz. if you can find an older one (without the new suspension) it weighs about 17 oz.

What total pack weight do you plan to carry?

The ‘old’ style Blast carries up to 20 lbs comfortably (25 lbs tolerably, IMVHO), the new one (reportedly) about 40 lbs, if 40 lbs can ever be considered comfortable.

Personally not a fan of the ‘one pack for all seasons’ philosophy… if I’m doing a quick summer ‘SUL-ish’ trip with a total pack weight of 11 lbs I’ll use a much lighter and more appropriate pack. I have 4 different packs ranging from 8 oz (MLD Core) to 24 oz (Arc Haul) depending upon season, location, conditions and weight requirements.

 

[Bob Moulder]

DC, yeah, I’ve read that. The word is that a single stay is good for flexibility but not so hot for load-bearing because all of is concentrated at the center of the belt.

This style seems to work on the Exped Lightning and Flex Capacitor, according to reports.

What total pack weight are you talking about??

[Stumphges]

Short trips about 20 pounds (base 10-15), but I’d like capacity to comfortably carry 40 several times a year with big bear barrel.

I need a pack for both types of trip but really can’t budget for two expensive ones.

The Blast/Haul look great, but I’m having a hard time looking past the more durable, and waterproof, XPac fabric of the Seek Outside packs.

[Bob Moulder]

Then get the Seek Outside… those packs can handle mondo loads, as Dave Chenault has shown. I’ve read oodles of good reports about them.

Dave now works at Seek Outside so maybe give him a call.

If you can only have one pack you must plan around the heaviest, bulkiest load.

[James holden]

one possible option is the HMG …. i dont know about the 4400, but the 3400 i tried on was basically a climbing pack fit …. it seems that they just swap a few features between their normal packs and ice climbing packs

perhaps someone with more experience with em can comment on the mobility and load bearing of HMG packs

the SO works just fine as a hiking pack … its really when you try to use it for stuff its not really designed for (climbing, etc) that you notice its lack of mobility and not so streamlined desgin

greg lowe invented the internal frame long ago and climbers/mountaineers have stuck with that design for decades for a reason …

but as always it comes down to how these packs FIT YOU

;)

 

[James Marco]

“Short trips about 20 pounds (base 10-15), but I’d like capacity to comfortably carry 40 several times a year with big bear barrel.”
I agree with Bob. You need to plan for worst case. There is nothing wrong with pushing the comfort range of a smaller pack if that is not your usual mode of travel, however. Bear balls are self limiting. You will usually find they are too small for more than about 7 days on average (more if you pack high density foods, burn off fat reserves, less if you eat a lot and pack low density foods.) They are heavy, but 2-3 pounds will not kill you. A lot of us go with both at different times: bear balls and hang bear bags.

“I need a pack for both types of trip but really can’t budget for two expensive ones.”
Eventually, you will need both packs. A larger volume pack capable of 30# to 50#, and, a low volume one capable of <30#. You wouldn’t be here unless you planned on being light, usually this means less than 20# base weight. Most here are much lighter. Unless you are planning to hike with a party of three and hauling all the gear for them, you should never need more than 30#. Somehow, I cannot wrap my head around a pack that weighs 3+ pounds being “Ultra Light.” SUL packs: <8oz, UL packs: <1#, Light packs: <2#, Packs: >2#. Even my 35L Murmur can fit a bear ball inside and weighs 12oz with a hip belt/sit pad and is comfortable at 20# for 20miles. If you do backcountry hunting, yeah, it is likely worth it though. Hauling out 100# of meat is no mean feat.

“The Blast/Haul look great, but I’m having a hard time looking past the more durable, and waterproof, XPac fabric of the Seek Outside packs.”
The durability is not really an issue. XPack and laminated cuben (DCF) are roughly the same. There are grades of each, however.

As far as articulation, skip it…a bunch of fancy words that mean nothing. The U shape us nice because it has a place to hang the hip-belt from. Coupled with the cross spar, it makes for a very changeable frame, either internal or external. Unless you use an external frame like a Kelty, all will flex diagonally. This is rather a minor point, since a five layer CCF pad in pad keepers will also flex diagonally. Gregory made one that actually shifted up and down with your hips using a couple rivets, but it put a lot of load on your shoulders because of this and wasn’t real successful. (Flex is nice, but you really need support.) Almost all no-frame, stayed, internal framed, and light external framed packs could say the same about their packs…

[Luke F]

Luke from Seek Outside here.

The SO frame is going to be a world different then something like a classic jansport external, which can fight you on the right-hip-forward-left-shoulder-back situation the OP describes.

When the pack is more empty/less tightly compressed the pack has more articulation, as the pack gets fuller and tighter it goes away somewhat. Depending on how you attach the belt to the frame there can be some added articulation there as well, I wear the belt on the highest position so I get quite a bit of movement out of it.

The frame being narrower at the top offers some mobility advantages over a typical full-width external, in that there is a little more shoulder room regardless of articulation (depending on body size of course). The wide bottom and vertically stiff frame of course means it will never ride like a skinny, flexible framed pack but that is the core of its heavier load performance and we try not to apologize for that. There are lots of people that don’t need what the SO packs offer, but for those that do there aren’t a lot of options that are similar.

Rodger, I wished I saw the world as black-and-white as you do, if I labeled everything I haven’t tried yet as marketing spin I’d save a lot of money.

[Michael Sirofchuck]

The most comfortable pack for me overall is HMG in a medium torso; I have the Southwest in 2400, 3400, 4400, and I also have a Porter 4400.  (I maintain residences in Alaska and Arizona – that’s why so many packs)  I have hauled some big loads with both 4400s and they were comfortable and handled the loads well. On the Guadalupe Ridge hike I carried two gallons of water in addition to my kit comfortably in my SW 4400.I used the Porter on a Harding Ice Field ski trip and even with my helter-skelter loading on the last day, the pack was as comfortable as a pack could be in those conditions(see photo below)  That said, anything 50 lbs and up I would defer to my Seek Outside frame pack – I bought it for deer/elk/goat/caribou hunting up here in Alaska and it has performed as well as or better than the Kifaru Long Hunter which was my previous pack frame.  One pack for every condition requires sacrifices at either the lower or upper end, weight-wise.

[Stumphges]

Luke,

Thanks for weighing in. In terms of freedom of movement and natural gait biomechanics, how does the Divide compare to an internal meant to carry more weight than is typical in this weight class, something like the Flex Capacitor?

James,

My initial plan was to get a budget 1.5-2# pack for 25# max loads and then get a Divide a little later. I picked up an REI Flash 45 used and an Exos-clone made by Bergans to audition for the little pack role but was disappointed by both. Then, having read some reviews of the Divide – guys saying that they pick it over their internals for many trips with light loads – I started thinking about the just one pack option. (I took note, also, that the Divide got as many votes as any other pack in the recent “Most comfortable pack” thread.) Maybe I’ll have to rethink the one bag strategy. Thanks.

Michael,

Thank you. That you find the HMG more comfortable than the Divide is good info.

 

[Luke F]

I can’t comment with much authority on the Flex Capacitor as I’ve only tried it on at a trade show, I would assume it had more articulation with the single vertical component toward the bottom. If I remember correctly the FC is very vertically stiff like ours, but has some pivot on the horizontal plane rather then ours which has it on the vertical plane. I would take a WAG that some of the articulation in the FC would go away the fuller and tighter the pack is, similar to ours.

Before using SO packs a Granite Gear Crown VC was my go-to pack, and comparing the two isn’t all that useful as they are a whole world apart. Obviously the GG was more flexible in every dimension, and much narrower as well. Other then that I have a few miles on some arcteryx packs, which while certainly more flexible vertically I didn’t think they have any flexibility advantage in other dimensions, and I get more articulation from a floating hipbelt on a stiff frame then I do from a flexible frame with a locked-in hipbelt.

In my case bike trips are about the only time I need more flexibility/articulation then what our frame offers, but I can only comment on the types of trips I do, which typically involve very little scrambling.

[JCH]

I’ve used many many packs, each different, each with their owm positives and negatives. Some with very rigid frames, some were all kinds of wambly.  Not one of them was the be-all end-all, so i guess i agree with Bob…there is no one single pack that does it all…if you can afford only one you have to address the biggest load.

And since we are disparaging marketing, this is my fav…

[Brad Rogers]

Pack fit is a very personal thing, but I compared the SO Unaweep 4800 to the HMG Porter 4400 and Exped Lightning 60 and much preferred the SO.  I am a 21″ torso and tried both large and tall Porters, and my wife tried a Windrider SW 3400 a few years ago, and other than a fairly novel (and expensive) fabric and simple well laid out design, there is nothing revolutionary about the HMG packs.  The SO frame is revolutionary – I am not saying it will work for everyone, or that it is the perfect pack for anything, as it isn’t, but it is a game changer in lightweight load hauling.

As for fabric, the only advantage I see to the 150d Poly-Cuben laminate has over the 210 XPack that SO uses is it can be seam taped, while the SO can be seam sealed on the outside.  Not a functional difference though, as the X Pack is waterproof and I have less concern about it long term ability to stay waterproof than I do the hybrid cuben.

The Flex Capacitor frame is innovative.  I haven’t tried it nor heard much about it so I can’t say if it works, but it is a different approach.  I can imagine it having plenty of flex, but I wonder if it has enough structure for 40lb loads.  The stretchy water bottle pockets are a turn off too.

One thing to note with the Divide is that it is built on their 24″ frame and best for torso’s 21″ and under.  It can be used  with the 2″ frame extensions, but I have been told that it raises the water bottle pockets too high to be used comfortably.  The Unaweep is built for a 26″ frame so long torso’s are not a problem and the new 3D water bottle pocket seems to work well and can fit two 1L powerade bottles in a pinch.  I think the Divide water bottle pockets are similar.

[Roger Caffin]

Hi Luke

Rodger, I wished I saw the world as black-and-white as you do, if I labeled everything I haven’t tried yet as marketing spin I’d save a lot of money.
A very healthy dose of doubt and cynicism works out a lot cheaper. Try it: you have nothing to lose but your debts.

I have built a number of packs in my time, and in all seriousness, I cannot see much difference in concept between the Evolution suspension and most external H-frames. I would be happy to be convinced otherwise, but I have this deep layer of pragmatism you see, backed up by more than 50 years of pack building.

Let me hasten to add that I see nothing the matter with the design of the frame/harness – I would need to be a lot more familiar with it to start nit-picking. I like external frame packs. I just don’t see much difference between it and other good designs.

Cheers

[Luke F]

in all seriousness, I cannot see much difference in concept between the Evolution suspension and most external H-frames

There isn’t a way to type this in the tone I mean to use but please recognize I mean this in the nicest way possible; I think you should look a bit harder before you comment if that is the case. Knee-jerk judgments from casual observations don’t add to the conversation.

The SO frame is an open inverted U with a joint at the bottom. There is no hard-mounted cross members and it is not an enclosed shape. I’m in no way implying it was the kind of movement you will get from skinny 7000 series flat stays, or frame sheet, but it is immensely different from the many externals I have used. Vertical stiffness is about the most it has in common with a traditional welded/jointed external, in most other tangible ways it has more in common with an internal frame pack.

[Author]

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