I knew the foam framesheet thing was going to be pretty hard/rigid, but I was surprised just how dense/hard it was. More like a foamed plastic than ccf foam.
Specs can be found on GoLite's Site. I'm really liking the hip belt, as it's nice and big with large pockets, and has full wrap around my hips. I also really like the center strip of 3D Spacer Mesh down the back and on the hip belts, as I get swamp back like nobody's business and the mesh should help with that some. Also, the pouch on the front is roomy, and can fit several items even when the main pack is full. The stretch mesh water bottle pockets are nice and large.
The Jam is a frameless pack, and should be fine as is for our normal overnight/weekend trips where my packweight is ~17 lbs with food and water. However, I love to mess around with my gear so...
Added some minor mods right off the bat.
Sewed on some fabric with grommets to the seam just on the other side of the load lifter straps on the inside, and on the sides and tied shock cord to keep a sheet of coroplast (corrugated sign board, pretty much plastic cardboard) in place. The corrugation is oriented so that the board can bend/flex vertically along the curves of my spine, but is rigid horizontally, so the pack won't barrel out when full. The reinforced seam area now comes over the top of the coroplast and securely holds it in place. This allows the load lifters to actually do their job.
Tossed in my quilt (no stuff sack), random cans of soup/broth, water bottles, sleeping pads, etc for a total weight of ~ 22 lbs.
Load lifter straps relaxed, pack pulling back on shoulders
Load lifters tightened, weight off of shoulders, transferred to hips (although, at this weight, removing the coroplast would allow the pack to conform to my back and carry just as well, don't really even need to use the hip belts for that little weight).
Also added some shock cord to the bottom to have some control of bottom compression instead of the all or none Kompactor system (for reducing volume when using as day pack or carrying less). The side compression straps have opposite male/female buckles, so the left and right straps can be crossed around the front to reduce volume even more, a pretty cool feature
At a load of 20-25 lbs and the stock foam is plenty for me, but the coroplast does
make it carry a little nicer, I think (I'll decide after hiking some miles in it). I might hit up Tap Plastics and get
some foamed PVC and form it to the shape of my back and see how that works for weights >25-30
lbs. I suppose I don't really need it since I did buy a frameless pack,
but it's fun to tinker so, why not?I'll add final weights, etc. once I cut off excess webbing/straps, etc. and update the review once I take it out on a trip.