everything i’ve read says the sleeping bag goes in the bottom of the pack — what does all that continuous compression do to the bag over time? why is that “the place” it goes? what’s wrong with putting it ontop in a looser stuffsack and let it fill (if there’s really much space left) the top of the pack?
denise
Mostly the bag goes in the bottom because you want the heavier things on top. Also the bag is typically the last thing to come out.
The closer to the center of gravity and the higher the heavy things are the less twisting will occur on the hips. That makes the pack feel lighter.
You don’t really need a compression sack. Just stuff you bag in a sack and then sit on it to get all the air out. Then quickly put in your pack. As the food dwindles you can stuff it a little less to take up room.
All that stuffing will cause the fluff to get squished over time but not much. And bags should be stored hanging up by the foot so they stay fluffy. You can refluff by putting the bag in the drier with a few tennis balls on low heat.
If you’re not sure how much pack room it takes up and you’re looking at a new pack take the bag to the outfitter and see how it fits in the pack. That’s a normal trick and they won’t think you’re weird or anything.
Bushwhack
My pack has an opening at the bottom and a zip divider to make a separate compartment at the bottom for the sleeping bag. I found that my bag wouldn’t go into that compartment no matter what I did. I tried to unzip the compartment, but the zipper seemed to be jammed. So I started putting my tent down there instead, and putting the sleeping bag up top to hold other heavy items close to my back. Eventually, I got the zipper unstuck, but I liked the arrangement so well that I stayed with it. The tent and ground cover goes into the bottom, my food and cooking gear in a stuff sack gets put in from the top, and the sleeping bag gets shoved in around that to hold it against the frame.
Ardsgaine
Bushwhack, I’m not sure that I understand.
If you want the heavier things on top, then that raises the center of gravity and makes it easier for you to fall or tip over. Thereby making it easier for you to take a bad spill on the trail. Physics dictates that you want the center of gravity as low as possible so as not to be top heavy and hence easy to tip over.
A top heavy tree would seem to me to twist just as much as one that is not top heavy, so I don’t understand the twist at the waist thing. Are there any hiking reference on this on the web by chance?
Not being at all critical, but just trying to understand and learn something.
See you out there. :cheers
Maintain
I’m not sure if I have the right verbage for this.
Using a pack with a frame sheet, the weight is supported by the belt. The belt forms a ring around your hips with the weight resting on the rear of the loop. The center of gravity should be at the center of the loop for maximun weight distribution/comfort. The farther off center the load is the more twisting force is applied downward at the edge of the ring. If you move the load up and closer to your back the load is spread more evenly over the ring and less downward twisting force is applied. It doesn’t make the pack weigh any less but if the load is spred out evenly and more in line with the body-straight down-it’ll feel lighter and be easier to carry.
Like balancing a basket on your head. If you hold it out in front it wants to rotate downward. If you place it on your head the weight is in line with you and pushes straight down. It’s a small difference shifting the weight in a pack but if you get it just right the pack bag will balance itself on the hip belt and you’ll have no pull at all from the shoulder straps. An effortless carry.
Bushwhack
Here, I drew a cartoon of what I meen. Am I any clearer. 
http://www.trailjournals.com/photos.cfm?id=37191
Bushwhack
I think I understand. You are saying it is a matter of getting the weight properly distributed in the center of the pack so that the force is downward, and there is no tendancy on either side of the pack for a twisting force.
Thanks for the clarification.
See you out there. :cheers
Maintain
I put the light stuff in the very bottom…ie bulky sleeping bag, then I add the heavier stuff in the center closely to the area between my rib cage and spine area or shoulder blades, ie tent, cookware. I then stuff clothing aroud this and towards the outside of the pack to keep the heavy stuff centered. Then I top it off with the medium weight food. Water bladder is directly against my back, which can be the heaviest thing I carry some days. The very top (fanny pack cover) I put map, meds, little things that I might use frequently…ie TP. I find little movement and the manufacturers suggested doing it this way. It also seems to fit the displacement theory that BW suggests…center of gravity is right against the back…in line with spine…
burn
suggest you want your heavy items as close to your natural COG as poss.This point lives in the center of your body,over pelvis aprox.belly-button high.Every possible way you could load will impact this differently and you will find the right one for you thru trial & error.Oo
Onlyone
The thing I kick my self for is not repacking exactly the same way every time. The last day before town I just shove it all in any old way and after a few miles the pack is all catywompus(sp), some times it gets wobberhockey’d too. Even putting your food bag a few inches off center will make you pack lean over to one side. Once you find a perfect set up stick to it, even if it is onagoglyn(the x is silent but not the q).
BW
It also depends on sex - guys’ COG is in the chest/sternum area, and girls’ COG is closer to their hips. We’re also usually stronger up top, so we’re more comfortable with higher COG’s for our packs. Women usually like heavier items lower in the pack than men.
Also, consider what you’ll be doing. For trail hiking, higher COG is more comfortable. For rock scrambling, a lower COG will give you more stability.
Jeff
Jeff
Quite right, my wife likes it low. I’ll also change up when the mountains and rock climbing hits.
BW
Carry a lighter pack and even-weight distribution is less of an issue. No need to be anul about it, just lighten that load the way you think best. Male or female, a 25lb-ish (including food and water) pack is a “Breeze” if, like me, you’ve also lugged a 50lb-plus pack up and down mountains all day long. No point chopping that toothbrush in half if you have a 5lb tent.
Ross
Ross
What is being talked about here is a very complex issue. COG has both a horizontal and vertical component. Your body has a natural COG, males as aforementioned have a slightly higher COG than females. Everyone’s COG is slightly different due to body style, etc.
Vertical pack weight should line up exactly like Bushwhack says (in line with the backbone) so that the pack does not have a tendancy to shift or ride to one side or the other.
The ideal situation would be of course to load the pack such as the natural COG (both vertical and horizontal) does not change, however very difficult to do precisely.
COG is very important for locomotion (walking, running, jogging, whatever). We are constantly shifting our weight to one side and forward or backward in order to locomotate. If we didn’t do that, we could not move. We naturally do it without thinking about it, so we get used to our natural COG. When we put a pack on and our COG has changed significantly due to the way the pack is loaded, we can instantly tell that it don’t feel right (COG has shifted).
So it needs to feel right, sit right, and carry right for whatever you are doing wheather it is hiking on level land or rock srambling.
See you out there. :cheers
Maintain
Right on, M. I spent a week one day repacking my stuff and never got it right. It always hung to one side or the other. Went to town and sorted the gear. It was fine after that. I guess after hiking with the same load day after day you soon know when it’s a pebble off kilter. One water bottle in the side pocket is enough for me.
Bushwhack