Jam2 Pack: Sleeping Pad as Frame?

Tony:

The "round" method seems to be the most popular. However, for me, I like to fold my pad flat and then insert it into my pack, flat against the back. To me, the three advantages of folding flat are:

1. more layers to the back make for a firmer "virtual" frame.

2. more efficient space utilization than a round tube

3. more "normal looking" pack (subjective, of course)

You can give both a try and see which method you prefer.

Tony,
I use the barrel method you mention. I've only used my Jam2 pack once, but it worked well with about 19 pounds of gear, food and water. I have a 48" RidgeRest I roll up for a barrel "frame" and stuff everything else inside and on top of it.
Chris

Forgot to ask… what pad do you use?

I have the original Jam which is very similar to the new Jam2 and use a closed cell foam in the barrel configuration successfully. I think the trick to that method is to pack the void space inside the "barrel" very dense so that it puts outward pressure on the pack all around and all the way up to your shoulder strap attachments.

IMO this method doesn't work as well with a smaller load, but, then again, if your load (weight) is small, then it's not as important.

I've yet to try a "framless" pack the uses a closed cell foam sleeping pad for a "frame" the can truly carry more than 20 lbs without becoming just a lump, not a pack that transmits the load properly to the hips.**

What is needed is for a packmaker to take the time to develop a proper "pad pocket" that can be internally or externally tensioned (tightened) AND the proper connection made between the "pad pocket" and the hipbelt for, you guessed it, that crucial weight transfer to the hipbelt.** In addition the pack needs to be able to compress the load against the pad.

When all this is properly accomplished I doubt that the material used to this end will weigh LESS than the two hollow aluminum frame tubes in my REI Cruise UL 60 pack – so until that day what's the point of frameless packs?

Eric

Eric,
I agree with your thinking in general.

I have found my use of the Jam limited to overnight winter trips when there is very little food and water involved but a lot of "fluffy" insulation bulk without the weight. I'll pack most everything for the wife and me in the Jam to fill the volume and let her carry the dense items like food in a small pack.

For other trips/weather conditions I either carry an appropiately small pack or my heavy duty Nimbus Ozone depending upon the situation.

I use Bens approach and agree that it works well. I've found the "barrel" approach hard to pack well. The trick is to pack it tight and to avoid odd 'breaks' in the load that can be caused by over packed stuff bags. If you use stuff sacks and try to pack 'em tight to save volume, try packing them loosely so that they easily conform to each other in the pack. Another trick that appears from time to time here is to make a light backpanel out of corregated plastic (often used in polical yard signs).

My experience with the Jam has been positive up to 20-25 pound…

"So until that day what's the point of frameless packs?"

Eric:

You won't really know for yourself until you give it a try. A blue foam pad is just about the best material for a "virtual" frame. Too bad it isn't comfy enough for me as a sleep pad anymore, which is why I "graduated" to a self-inflating pad. Luckily, the latter also works well as a frame.

Using either pad folded flat and inserted into my pack — I have not found the need for a pad pocket. YMMV, but here's why:

1. With the pad in flat, you pack a frameless exactly the same as an internal. Once you are done, you cinch the pack tight and everything stays in its place. No need for a pocket. For me, such a pack is comy to 20-25 lbs. — better when closer to 20.

2. With a half-empty pack (say on the outbound leg) — you can still maintain a pretty tight load by simply letting your sleeping bag take up any available space. In fact, I never use a stuff sack for my bag — I let it "self compress" as needed.

Now, maybe a pad pocket can extend carrying comfort to beyond 25 lbs — in which case then it would be a great feature. But reading the different posts, I haven't read much feedback saying this is so.

Tony,
I use a Jam2 pack and have a GG torso pad which folds flat to form a decent backpanel. My pack is modified, as I have removed the hydration sleeve, the foam backpanel and the pocket that holds it, so all I have left in the back of the pack is the dyneema. The egg crate foam on the torsolite makes a very comfortable frame with the pack loaded, and stays in place all day. I'm guessing what I do is very similar to Ben's method.

Ben,

I sleep cold, so I use the regular size (72" inches)Prolite 4, which gives me 1.5" thickness.

Flattened out, I am guessing that it is 1" thick.

I am expecting to carry a load of up to 25 lbs, but have a base weight as low as 12.83 lbs.

I plan on using this pack on the Tahoe Rim Trail in Sept of this year.

(Side note: I am toying with the idea of using the Torso Light pad sold on BPL and the Jam2 under my legs, but I sleep so well on what I have now that I am hesitant to change…any thoughts or experience from the cold sleepers with the Torso Light Pad?).

-Tony

I have used the BPL torsolite many times but only with one night of use. A good night of sleep is so important to me. I can put up with one uncumfortable night of sleep- but my hiking is effected [GRUMPY]. A good large sleeping pad is LUXURY!!- its worth every once or pound. Sleep happy and hike happy- sleep like a KING!

Tony:

My pad is an REI Lite Core — which has the same thickness at your Prolite 4. However, mine is 2/3rd length, which I augment with a section of blue foam pad at the foot end.

The Prolite should work very well for you — just fold it in half length-wise, then fold down to the size of your pack. If the Prolite is still too long for the pack, try inserting it like an "L" instead of a flat "|". To me, 25lbs approaches the outer limit of the comfort zone of a frameless pack — but as they say YMMV.

Let us know how that compares with the barrel method for you.

I have the Prolite 4 and the first generation Jam. I've tried Ben's approach and the barrel method. They both work. The trick is to leave some air in the mattress and close the valve. This gives structure similar to ridged foam. I've even blown more air in the pad after my pack is packed to adjust the feel. If you don't close the valve then the air mattress will probably not provide the needed support.

Tony,
I took a ridge rest, cut it to torso length, and then slit it half-way through. I placed the slits so that the sections would fold into themselves without bunching. I reinforced the slits with 3/4 fiberglass strapping tape. This arrangement allows the pad to fold very flat and become very stiff. I left the factory backpad in because I use the pack for insulation under my legs. I have found this system to work exceptionally well at 25 lbs.

Eric Noble's idea of leaving air in the Thermarest mattress was similar to what I was thinking when reading Ben's posts.

Can an internal "pad pocket" of lightweight ripstop be made that will permit just about any inflatable mattress to be inflated AFTER insertion in the pocket to make the back panel rigid yet pliable? Methinks this avenue should be explored by packmakers. Possibly closed cell pad afficiandos may not like it as well unless such a "pad pocket" would work fairly well with their pads as well.

Eric

Thank you to everyone who took the time to read my post and for taking the time to give me your advice.

Definitely going to be playing around with my pack this weekend to see what works out best.

I took the Jam2 out two weekends ago on a leisurely 3 day hike to Lake Vernon in Yosemite and the pack felt okay with 26 lbs in it, but I did notice that the top of the bag hung back off my shoulder blades quite a bit.

I am used to having the stabilizer pull straps to pull the top of the pack closer to my pack on my Gregory Z55, which the Jam2 does not have.

Will a full pack, I guess it acted sorta like a frame, but using it this weekend as a day pack, I found that I would have benefited from some sort of frame/internal support.

Ben…as usual, great insight on how to do things a different way that I had not thought of or hear of before.

Thanks again.

-Tony

My Jam2 just came in the mail on Tuesday, and I got my first chance to practice pack it last night. Because I had no idea how to go about packing it, I went with the "barrel method" in that I wrapped my Therm a Rest self inflating pad and filled the center with my gear. Now, I still have my stupid heavy Eureka tent, but even with that, I was very happy with how the pack held up using the sleeping pad.

I do have a bit of a problem with the shoulder straps not exactly hitting my shoulder blades where I want to, but also it was my first time packing it up with all the gear I typically take with me. I'll probably be happier with it the more I use it.

Overall, though, I love the little guy and am very happy with the purchase. The barrel method seems to work well, but as I plan to replace the ground pad in the next year, I'll have to play with it more.

Anybody have experience with a Big Agnes memory foam pad? I have a Jam 2 and I’m thinking about getting the big agnes pad since I sleep so well on a memory foam pad in general, it’s relatively inexpensive, and it’s versatile (see below). I realize it’s open cell, so won’t insulate as well.

The pad is called a “kit” because it has a full-length pocket that can be used for an inflatable mattress(or a thin closed cell foam mat, or other mat ad nauseum). Here’s the info on REI
http://www.rei.com/product/775932

Any opinions, tips or suggestions?

hi,jane. i have had a big agnes system for many years. the quality is excellent. i have a 72x22x2 mummy style that fits in my horse thief bag. i love it. have never had any problems with either the bag or pad. the pad is insulated which works well in minnesota. i did get a new pad for this year, through big agnes. a insulated inflatable because it is thicker, as my hips were bothering me. i tried it out and worked just fine in 35 degree nights. it takes about 20 good size puffs to blow it up, which isn't a problem for me. hope this helps….vicky p.s. the first pad i had was an thermarest type pad which inflates on it's own, so guess memory form is different. sorry

The specs look strange. 2lbs.13oz. and 2.5"
This may be the weight before adding a pad to the pocket and the thickness after, but I could be way off. Check this one out in an actual store before buying.

Thanks Victoria and Jeremy. I will continue to check it out. No stores nearby :-( but I'll do what I can.

Victoria, do you use a Jam 2? Or does anybody else have experience with Big Agnes pads and Jam 2?

Thanks!

sorry jane, but don't know what a jam 2 is. maybe only out your way. i purchased my equipment right from big agnes web site…..vicky

Vicky,
Jam2 is a backpack made by GoLite.
http://www.golite.com/Product/proddetail.aspx?p=PA5251&s=1
Hope this helps.
Chris

I'm reading questions and comments in a few of these posts about the posters' packs not fitting correctly, lining up with their shoulders, 'gapping' at the top, etc. This is most likely due to a pack with either improper torso length, improperly adjusted straps, or just plain incompatibility. Make sure you have a pack that fits your torso; no amount of fiddling with sleeping pads will make a pack comfortable if its not the pack for you.