I recently bought a Jam2 (currently in the mail) to replace my GoLite LiteSpeed pack. I figured I'm at the point now where I can go frameless.
A day after paying for the Jam2, I got to thinking.....how much lighter is this pack then if I just removed the internal frame in my LiteSpeed? The LiteSpeed's frame is easily removable because there is a velcro flap that opens and then the whole thing slides out.
So I removed the frame and weighed it at 10oz.
GoLite claims a full pound difference between these packs on their website (1lbs 10oz vs. 2lbs 10oz). So with the LiteSpeeds frame gone, it should only weigh 6oz more than the Jam2.
That's significantly more I guess, but my LiteSpeed also weighs 2.75oz less than GoLite claims (without modifications). I weighed mine on a very accurate professional scale at work at 1110 grams or 2lbs 7.25oz.
So if a Jam2 comes in right on the claimed weight, that would mean I've only saved 3.25oz for all my troubles. Hmm...I'm not sure that's worth $100 but I guess I can sell the LiteSpeed.
The reason I started this thread is twofold:
1) Is there any reason not to use the LiteSpeed without it's frame? Will the Jam2 carry better since it's designed as a frameless pack?
2) Perhaps the LiteSpeed is the superior pack, because for just a small 3oz weight penalty, you get a pack that can be frameless or internal frame depending on your trip. For people who want to try out frameless hiking it seems like a good way to test it out without committing to buying a frameless pack.
Besides the weight, the key difference between these is that the Jam2 uses your classic roll top closure whereas the LiteSpeed uses a zip. I've been really happy with the zip because it's super quick to open your pack and you can open it much further than a roll top pack, but on the other hand the roll top would win out if your load is a bit too big for the pack. It can be a pain trying to cram all your stuff in the LiteSpeed if you've over packed.
Besides this, they seem pretty similar. They both have hip pockets, the Brock padding, whistle, similar compression straps, compPacktor system etc.
The LiteSpeed does have the load lifter adjustment to pull your bag closer to your shoulders which the Jam2 lacks. These seems like a possible advantage in comfort.