Let's Talk About Your Body, OK?
Backpack Types By Suspension System.
– Hang for a while. –
Hang out. Hang freely. Hang often. That sums up the backpack's creed. Packs don't really talk to me so I'm guessing a little here, but it sounds good. Suspension is what it's all about. Suspension, suspending, being suspended and all. It's a hanging thing.
You want your pack to hang and hang well. You want it to be suspended but not like a ball on a string or some droopy useless stuff sack hanging from a random piece of strap. Not swinging and swaying around unreasonably. The pack is something you need, and something you want to have along but while you carry it, it should stay away from your field of view. No flapping around. No banging and bumping into you. No bruises or heartache. Leave those at home, eh?
Strictly speaking, a pack doesn't need suspension, you do. If you want to go along when your pack heads out for time in the back country then you must stay connected to it. So it can't get away. And you want to be in some kind of comfort too. That's what it's all about.
Suspension is what allows you to take the pack with you. The suspension system suspends the pack from your body, which in a way becomes part of the pack. If the body is water's way of going uphill then the body is also a pack's way of going on vacation.
You could stuff all your things into a paper bag and walk around with it in your arms. That would work in dry weather, for a while. Use a duffel bag parked on your shoulder? Sure. Lay everything out on a big tarp and then drag the tarp around by one corner? OK. Kind of tricky during stream crossings and so on, but who are we to judge? In fact a lot of this has been tried, time and again, over and over, and people keep coming back to the idea of a pack hung solidly but comfortably on the good old hoomin body.
If you study that body closely (yours, or preferably one better looking than yours, which can be a fun hobby all by itself), you will notice some things. Lumpy parts, for instance, in relatively odd places. The lumpy parts of some people are lumpier than others, and lumpier in places that are more or less odd, varying from person to person. Men have some pretty lumpy (and tender) things, but they are tucked into an obscure corner that isn't good for much else, and is too narrow for a backpack.
Women, now. They have different lumpies. Bigger ones generally, covering a larger area. Men also have a little bit of this, but not enough to worry about. Male lumps of that kind are vestigial and kind of gross if you think about it. So don't.
It so happens though that the human torso is kind of big, and kind of flat, except for that problem area with some lumps on the front side.
Keep that in mind for a minute.
Now another problem with humans is that they have only the two hind legs. Humans are not stable and horizontal and reasonable and supported by the four stout uprights that most legitimate animals have. No. Humans have this need to stick up above the landscape like posts and balance on only those two legs. This must have taken quite a while to get right, as you can see if you try to assume an upright position without first gaining full consciousness, as must have happened to our ancestors. So uprightness is an acquired skill.
Humans are goofy. We simply have to deal with that. But then there are some other things going on.
If we want to stay up on our hind legs and get a grip on something we have to grab it while it's in front of us. Our arms don't work off to the side so well, or out back at all, and if we grab a double armful of something big and heavy in front then we have to lean backward to carry it, and that is awkward as all get out. We aren't made to lean back like that. Leaning forward is easier, but not with your arms full.
Hmmm.
Then the eyes. Hey, only two eyes again, and both up front. Grab that 90 liter pack in your arms, get a good solid grip on it, hold it up high, lean way back and try to walk. Uh-uh. No go, babe. You can't see diddly. Got the dang thing in front of your face, mooshing up against your nose, blocking your entire line of sight. Not good at all.
Not to mention that it's rubbing your lumpy parts raw.
So then. What else?
Guess where that takes us — yep. Out back. This is a miracle. Either someone actually planned way ahead, or an unknown drone in the design department really goofed, or it's a great example of random adaptability in action. Find a mirror and look at your back, or check out someone else's and assume that you are kind of the same. No. Higher, you pervert. Between the waist and the tops of the shoulders.
Whoa, there. What do you see?
A broad expanse of mostly flat, unused real estate. Kind of bony, sort of, muscular in a way, sort of. Mostly in between the two extremes though. Not especially pretty or anything, and so it's not much fun to look at but it is strong, and out of the way. Stick a big bag there and try to carry it around. Whoa again. Hey, not bad! Makes you lean forward, the way you sort of do normally. Keeps your arms free for grabbing at interesting things or picking your nose and so on. Put something on your back and whatever it is you put there is out of sight for those of us with just the two eyes on the front side of the head.
Could work. Just might work. Let's try...
Yep.
It does.
And it has worked for a long time. We keep getting back to the same old idea. Put the pack on the back, guys.
Now the question is how.
– Hang me outside. –
There is really only one main way to put a pack on one's back and that is with straps that come out of the top of the pack, go over the shoulders, and then loop back under the arms to attach to the bottom of the pack. Add some kind of extra strap around the waist or hips, and you have everything covered. The pack is now connected to the body and suspended.
But there is a little more to it.
If the pack is only a sloppy, loose bag like a stuff sack, then gravity will make a mess of it. A simple bag will slide down toward the ground and make an annoying nest in the small of your back. Right over your butt. Maybe even on top of your butt, where it will bounce and rub like crazy as you walk. So packs had to be modified a bit to give them some strength and shape, and to keep them up high where they belong.
No butt bumping allowed.
The mods needed to achieve this desired state of perfect perch are at the core of the three suspension systems that we have to pick from. They all revolve around frame type, which you've already heard about, unless you're reading this from back to front. If so, then don't be surprised when you come to that part.
The purpose of a frame is to define the pack's shape and to spread its weight so that the pack can be carried more comfortably and more efficiently.
The frame types are:
- External
- Internal
- Frameless
Option number three (frameless) sounds like a contradiction.
How can a frame be a frame if it's not there? Isn't a frameless pack simply a nasty shapeless bag with shoulder straps? No, it doesn't have to be. In order to build suspense and use it to keep you awake we'll leave the explanation of how a frameless pack can have a frame until last, and start at the easy end, with external-frame packs.
External-frame packs are the oldest type of framed pack, dating back ever so far. Remember Frozen Fritz? Besides him, people have been using pack frames of one kind or another all over the world since the beginning, or as close to it as you'd want to get without a good bright light, a pointed stick, and a few friends to cover you.
When we use the word external, it means that the frame is outside the pack. Or put another way, the frame is external to the pack bag. The thing we call the pack actually is a bag of some kind, and it attaches to the frame, and then hangs from the frame. This is pretty good in some ways.
For one, although the frame and the pack bag are made for each other, they are made separately. The frame can be made as a good frame, and the pack bag can be made as a good pack bag, and either one can be cleaned or repaired or replaced separately. You can even have a sturdy and indestructible frame and then design and make a completely different pack bag than the original, or copy the original pack bag design but make it over with updated fabrics. And so on.
Along with all this stuff, external frames are rigid, so they are great at maintaining their shape and they provide sturdy attachment points for hanging the pack bag, and for attaching shoulder straps and a hip belt. The strength and rigidity of the external frame allow for carrying heavy loads. If you find that amusing.
Balance on even ground is good too.
Keep the load up high in the pack, lean forward slightly, and let the pack rest against your back, where the weight of the load is transferred to your skeleton. This process allows the weight of the pack to easily align with your own center of gravity. External-frame packs also keep the pack bag (and therefore the load) away from your back (by a small amount). When done right, this configuration allows a bit of ventilation in between the pack and you, and the protruding frame also offers lots and lots of places to lash gear, in case you want to bring along your TV set, or your cat (which will, obviously, require its litter box, the old familiar food bowl, and a generous selection of snacks and toys).
– Stiffen my innards. –
Internal-frame packs are like all this but different.
Dealing with an internal-frame pack is something like having clothing with a hidden agenda. A pack like this has its own bones, its own personality. It has a shape that seems cuddly and soft at first but the pack won't really comply with every one of your desires. Some things, yes. But not everything.
So what's the deal then?
An internal-frame pack is built around a fixed idea, and that idea is the frame, but the frame is inside somewhere. The frame is part of the pack.
The frame might be metal, like an alloy of aluminum, or it could be plastic, or a combination of materials. Sometimes the plastic frame elements are fairly wide, stretching across the width of the pack, near to your back. This arrangement is called a framesheet. Some internal frames are customizable — bend the frame pieces (the stays) until you are happy with them, and then go for it. The stays in a pack are similar to the pieces of whalebone in a 19th-century corset. Long and narrow, flexible, but not so kinky as a full corset. These stays are usually aluminum.
Whatever the details, the purpose of the frame is to keep the pack stretched out vertically, so the top of the pack is up by your shoulders and the bottom of the pack is down by your hips. You want the two ends to stay apart and not to wad up in the middle. This configuration helps to keep most of the pack's weight on your hips and only a little of it on your shoulders.
If you run your arms through the shoulder straps of an external-frame pack and tighten the hip belt you have sort of attached your body to the pack the way you would chain yourself to a tree. It may be an intimate relationship, but not necessarily a loving one.
Internal-frame packs are a little more intimate and a lot more like lovers.
Internal-frame packs ride closer to the body. Putting on one of these packs is like putting on a coat, or a prosthetic hump if you like that image better. Putting on one of these packs is closer to inhabiting it, more like getting into a tree costume than chaining yourself to an actual tree. Yes, the intimate aspect extends to ventilation too. There is nothing, ventilationally speaking. The pack wraps around you warmly, in a great, goofy hug, from behind. The two of you breathe in unison, and sweat together. Often profusely. And the sweat lingers and pools. Right between the two of you.
Descendants of climbing packs, internal-frame packs are better for off-trail use because they carry loads lower down and also closer to the body. A lower center of gravity is more stable on rough, uneven ground, but less efficient on smooth and level trails. These packs also tend to be sleeker and a little less voluminous than external-frame packs, and rely more on compression and careful packing to help contain the load and provide that last bit of rigidity.
– Make mine imaginary. –
So now, eh? Like now we come to the center of the problem. How do you make a pack without a frame and still consider that no-frame to be a frame type?
This is your koan, Mouse Butt.
Though.
Since we get to make things up as we go along it shouldn't be too hard to imagine. The hard part of fantasy is being consistent. Make things sound vaguely plausible. Instill confusion with persistent hand waving, keep it up, and you can get people to the point that they will swallow anything and go home satisfied with that glazed look still in their eyes, little flecks of drool still damp on their shirt fronts.
It can be done. The term for it is suspension of disbelief.
Let's do it now for frameless packs. They require it.
The no-suspension suspension is...the Suspension of Disbelief. (Capitalized to make it seem even spookier, 'K?)
Frameless packs are special. They are like close friends. Really close friends.
Ever have a friend you could talk to about anything? Someone who was closer to you, in a way, than your parents, your sisters or brothers, your spouse? Your cat? Well, maybe not. That is stretching it, but on the other hand your cat doesn't understand anything that comes out of your mouth unless you have a sardine by the tail and are trying to be cute at feeding time.
So back to the story. Frameless packs are different. Frameless packs are special. Frameless packs do not have frames. But frameless packs still have to act like they do have frames, so how do we make this work?
Ahhhhh, tricks.
We become tricksy.
You probably have a frameless pack and use it to carry a sandwich, a bottle of water, and a windbreaker when you go hiking down by the river. Nothing fancy. Short trips. It works. You never bother to think about it. You call it a day pack.
Here is why it works. Two reasons.
First reason. One syllable, six letters — weight.
You carry very little weight in that day pack.
Second reason. Four syllables, eight letters — rigidity.
The day pack has some rigidity built in. The pack is a little stiff but not very stiff. Just enough. Just enough to handle the tiny bit of weight you put in it. Usually that bit of stiffness comes from the padding in the back, where the pack lies against your body.
But.
Sometimes you stuff that sucker full, and head out for the whole day and maybe hike 15 miles. How does that work? The same way, by a different route.
On those days when you need six sandwiches and two big water bottles and a camera with three lenses, and a heavy rain jacket and rain pants, and a warm cap and insulated gloves, and the extra odds and ends to fill out your 10 essentials for safety plus some jerky treats dog snacks for your friends, you have a fairly big wad of stuff.
A little while back we used the word wad in a negative way. Usually it is negative, when you are talking about packs, or things in your mouth, but not always. This is a positive wad, this one is.
– The power of wad. –
Take a small, light, frameless pack and stuff it so full that it begins to gag and right away the pack is stretched to the limit. It throws its own version of a hissy fit — it gets rigid. You have to be careful to fold and load things in the right way. Soft things near your back, folded flat. Then hard things farther out. Heavy things placed where they will carry best. Necessaries where you can get at them in a flash.
So you stuff this little pack to the gills, and maybe it even gets heavy enough that it bugs your shoulders by the end of the day, but it still carries pretty well despite that.
What you have done is turned the whole pack into a frame.
Ahhhhh. Now so clear!
That's right. Amazing but true. (So true!) You have turned a frameless, mostly shapeless bag into a tight, clean carrying machine. You have witnessed the miracle of the framed frameless. Or the frameless framed. Or whatever. Try not to get dizzy. Let it sink in.
This is what ultralight packs are about.
When you have a small light load you can fudge and trick a pack into thinking that it has a frame. Your body may not even notice.
No, wait — it will.
Your body WILL notice.
It will notice that you are carrying almost no weight. That won't be true, but your body will think it is because apart from limited areas of your brain (if they are switched on at all) your body really isn't all that bright. If you are carrying only 10 percent to 15 percent of your body weight then your body won't really notice.
It can't do percentages, especially the smaller ones.
Small frameless packs work really well for off-trail excursions where the ground is rugged and random, or in places where you have to squeeze between trees and shrubs to make progress. On the other hand you won't suffer on a groomed trail, as long as your frameless pack is well made, is packed right, and you are not carrying much weight.
The most common way of framing a frameless pack is to press-gang your sleeping pad into service. There are two ways to do this.
– Om mani. Pad me. And hum a happy tune. –
Way the first: Fold that sleeping pad and keep it against your back, either inside the pack or in a custom pocket outside the pack but still against your back. Some packs are made with a special pocket just for this. Standard sleeping pads, inflatable or not, are 20 by 48 inches (51 by 122 cm) and fold neatly down to 12 by 20 inches (30 by 51 cm). If you have an inflatable pad you can also control how stiff it is by how much air you leave in it. Way, way cool. Comfy too. Put the folded pad in the pack first, then finish by filling the pack with gear.
Way the second: Roll the sleeping pad into a hollow cylinder and lower this into the empty pack, then stuff your gear inside the sleeping pad. Stuff the absolute snot out of it and you have a stiff pack.
Either way works but once you get up over 20 pounds (9 kg) or so, you begin skirting the discomfort zone even if you habitually wear pants and not a hiking skirt.
For weights from 25 to 30 pounds (11 to 14 kg) you can do yourself major kindness by taking frequent breaks. Usually if you have a relatively heavy ultralight pack it's because you are starting a trip and have lots of food (which you will eat up as you travel, if you have any sense at all), or because you are carrying a lot of water (like on a short hop from the nearest stream back to your camp site).
If you are on a long trip and have to eat food to get the pack weight down, you find out how slowly time really passes when you are in pain, and how little you need to eat, relative to the pain. If you are carrying a load of water a few feet, then stop whining already, it's over before it starts.
– BDSM. –
Bag Discipline through Strap Manipulation is another way to do it.
This is used with another kind of frameless pack, one that achieves rigidity through compression and careful loading. This kind of pack has to be designed for compression, and has a relatively narrow range of useful volumes. Too much stuff and you can't get everything in. Too little stuff and you have a limp, saggy, bent bag.
Don't want that babe, so pay attention.
In the right volume and weight range though, you have a lot of control and can fine tune the pack by where you put your gear and how tight you cinch things down.
Lots of frameless packs have no hip belt. Most have at least a waist-level webbing strap for stabilizing the load, and this can take a bit of the weight too. Some packs have removable hip belts. What's best for you is what's best for you. Any sort of hip belt or waist belt can take a lot of weight off the shoulders, and even a 15 pound (7 kg) load can be severely annoying or painful near the end of a long day.
Frameless backpacks are usually light and small. They collapse down to almost nothing when empty, and are simple enough so that you can make your own. That's the pro side. On the con side, you have to keep down the weight and volume of what you carry and have to educate yourself about how to use the pack. Unlike the more bulletproof framed packs, ultralight frameless packs are made of lighter, more delicate materials and rely on intelligent stuffing and cinching to be both comfortable and efficient.
– Rules of the load. –
The type of suspension affects how the load is carried. The stiffer your pack's frame the more precisely you can position the load, up to a point. But if the frame is big and heavy and also absolutely rigid it will stand away from your body quite a bit, and ultimately will limit your options. Generally on smooth, even trails a load carried high and forward is best. Lean your body forward a tad bit and the center of mass of the pack falls in a line through your hips, which is good, because that's how to stay balanced. This is easiest with an external-frame pack.
Get a couple feet off the trail though, and this arrangement gets wobbly. On rough ground or threading your way around rocks or through brush, a high load will zag when you zig. Call this the pathless polka. It's the tidy trail tango versus the boulder dodging bossa nova. It gets tedious. You really cannot do a rucksack rumba with a Kelty Tioga. In comfort.
And any external-frame pack like that will hang you up in brush.
Internal-frame packs do better off trail. With one of these, you carry the load lower down, which isn't so good in a theoretical sense, but in practice it is not so tippy and wobbly. These packs wrap around the body better, and hang on tighter. They don't have so many projecting parts to snag on the landscape. They can get hot though. Your back will sweat and make your shirt stink. (Tip: Learn how to rinse out your clothes whenever you get a chance.)
Frameless packs are even more flexible, within their weight limits.
But load a frameless pack too much and you will hurt the pack, or maybe even destroy it, though you have to work hard to do it. You will hit the limit of your pain tolerance first. Stay within the pack's limits and you can go anywhere as long as you plan ahead and have the experience to handle it.
With an ultralight frameless pack you can lay the load down low, like ballast, in the small of your back, or stand it up vertically, along your spine. Either way works. One of these packs is not as good for heavy loads as an external-frame pack but you aren't going to carry a heavy load. Not far, you won't.
No matter what style of pack or type of suspension you use, well-made shoulder straps help a lot, as well as at least a waist belt for stability. The heavier the pack, the more suspension matters, and the more important the hip belt becomes.
– Clips and straps and buckles. Oh my! –
There are basically two kinds of hip belts. One is a plain webbing strap, and the other is shaped and padded and might be scary just to look at.
OK, you already know about the webbing. You can buy webbing straps for lashing extra stuff onto your pack. Take the same material and put a big buckle on it, then attach one end to each side of your pack, down at the bottom. Bingo. Waist strap, stabilizer strap, whatever you want to call it, with the buckle over your belly button.
This thing helps a lot but is hard to put much weight on, for any length of time. The strap can be an inch wide or more, but making it wider does not help a bunch. Like training wheels on a bike, it's sort of helpful in the alley but out of place during the Tour de France. Not a professional grade solution.
If you need more support than a simple webbing strap offers then you need a hip belt. In other words you need a real hip belt. At the bottom end this is a simple sleeve of fabric with some padding inside, and a buckle so you can get a snug fit. Slightly fancier hip belts slip into a harness on the back of the pack and are removable. OK, fine. Mostly that's about it for lightweight packs. A padded strap.
Go to an outdoor shop and take a gander at some of the fancy hip belts. You will need an advanced degree to even begin understanding how they might be made, or from what. Plastic, fiberglass, carbon fiber, aluminum, titanium, gruffy dust — all kinds of stuff goes into them. Several layers of different density padding. All that. These hip belts can support huge amounts of weight, all of which goes right into your hips and runs down your leg bones and into your feet, which then hurt like crazy. There are probably industrial designers who do nothing but worry about getting the last drop of performance from hip belt design.
Since every person has a different body, walks a different way, and carries different amounts of weight at different times over different terrain, this is a hard design problem. Which is a good reason to carry less weight. Less weight means you can get by with something simpler. And your feet don't hurt as much. And you can forget about words like performance. Or about phrases like carry immense loads in comfort. Love that one.
On a light pack a hip belt mostly stabilizes the load. On a slightly heavier pack, combined with some kind of frame or frame substitute, the hip belt takes all or most of the load, but it still doesn't have to do a whole lot.
A hip belt is at the bottom of the pack and pushes up on the pack. Shoulder straps are at the top of the pack, and the pack hangs from them. You know all about shoulder straps. For a really light pack they are the end of the story. Just slip into them and all is right with the world, as long as your pack is light. They just work.
Up to a point.
You only want a certain amount of weight on your shoulders. The more weight you have in your pack the more of it you want flowing into the hip belt. Shoulder straps are good up to five or six pounds (about three pounds or around 1.5 kg per shoulder) for a long day. More than that and your shoulders get really cranky. They begin to ache and whine and won't stop. Put 50 pounds (23 kg) into a pack and you will want at least 45 of those pounds on your hips, and even then you will wonder why you ever brought along all that crap.
Shoulder straps are good for keeping the pack close to your body and keeping it stable, even more than a hip belt. But they are not so good at supporting a lot of weight. They are good for only a little weight.
Shoulder straps can be plain webbing, but this gets old really fast because these straps run over the collar bones, which complain a lot about the situation. Padded straps are the best way to go for every kind of pack. Padding conforms to all your personal nubbins and evenly spreads the weight. Evenly spread weight translates to a happy body with no angry nubbins.
Straps can be straight, and you'll see these on a lot of home-made packs and some simple, very light and low-cost manufactured packs. These shoulder straps are straight but padded. Since the route of the shoulder strap is curved from the middle of your back up over your shoulders and down your chest and sides, straight straps are not the greatest design decision, but they work.
– Work it, babe. –
One way to make them work is to attach straight shoulder straps to the pack not way back between your shoulder blades but at the top of the pack, at shoulder level, which means that there is not so much shoulder strap back there. Straight straps made this way skip the whole back area and ignore the around-the-neck area, and end up leaving out only a curve or two. This is good enough for very light packs.
Another way straight shoulder straps work is because of weight, as in the lack of it. A very light pack doesn't put much pressure on shoulder straps, so they don't dig into your ribs with so much determination. The pack maker can skimp and you, the pack wearer, hardly notice. It still feels OK, mostly.
If you carry more than 10 pounds or so (4.5 kg) you want curved shoulder straps.
Curved shoulder straps are sort of S-shaped, and they wrap around your body better. Remember one of those skiing cartoons where the ski tracks go around a tree? Not both to one side, but one ski track on one side and the other track on the other side. Curved like that. Curved shoulder straps detour around the neck and then down the breast and then curve the other way and run along the side of the rib cage. Curves make straps comfy. Comfy is good.
Curved shoulder straps look simple but if you make your own pack you'll see it's more than a no-brainer. (Even straight straps are a little tricky to make at home.) You need to get the curve right, and the space between the two straps, and the length, and the amount of padding. But curved straps do fit the body better.
Heavy, large packs from the big makers have shoulder straps made of fancy materials with lots of adjustments. These serve the same purpose as all other shoulder straps but when you are carrying a whole bunch more weight everything has to be exactly right, so these straps are almost infinitely tunable.
No more than five to 10 percent of the pack's weight should come through the shoulder straps but you still have the balance issue. With a 50 to 60 pound pack (23 to 27 kg), balance is really critical, and even without a lot of weight ending up on your shoulders you still need to be strapped in tighter, so straps have to be more precise.
In other words, fit is important. This is where industrial designers earn their pay with dual density foam and all kinds of dials and levers to operate. You might need a license, issued only after rigorous study and a driving test, but you will swear less once you get moving.
No matter which way you go though, the basic ideas in suspension are to hang the pack from your body (if you carry a light pack) or strap your body underneath one (if you have a heavy pack).
So then, are you happy now?