I'm making my first MYOG pack, which is also my first foray into frameless packs. Straps and hip belt pieces are done, and I've mounted them on a mockup of the pack bag. The mockup has worked well to adjust strap angle, spacing, length, etc. and make sure the pack volume is right (30+ liters, or 28" X 12" X 6" including 8" extension collar).

Here's the problem: Using either partly inflated Prolite or CCF pad, folded or burrito-style, the virtual frame becomes somewhat convex when the pack is loaded. I find this uncomfortable (or at least, it feel weird).

If I reach back and tug the top of the pack toward my shoulders (as load-lifters would) it feels better. Should I add load-lifters and take the (minor) weight penalty? Is the rounding-out of the pack just in the nature of frameless packs? Will the pack conform to my back better after a few miles? Will compression help? (The mockup doesn't have a compression system, but the actual pack will.) Are there other virtual frame systems that work better?

I'd like this to be my go-to pack for trips up to 5 days or so, and starting pack weight will be generally 15# or less, with ~7# base. I'm trying to keep the stripped weight of the pack around 8 oz, using dark gray Xpac (vx 21?) and 1.9 oz silnylon, with minimal features. Ideally, in its lightest configuration, the pack will be part of an SUL kit I'll be trying next season.

Thanks for the input.

Edited by DavidDrake on 09/24/2011 12:02:31 MDT.

I have no experience designing or making a pack.

Ultralight packs are most comfortable when packed LOOSELY so that the contents can conform to your back.

I think this works best up to about 15 lb or so. And at those weights you can carry it all on your shoulders without problem too. You dont need much transfer to hips

However, I do like having a sleeping bag in ~7x13 stuffsack at the bottom too. This stretches the pack out sideways and makes it less round, and the rounded shape fits good into my lower back. When load lifters pull it in, the folded CCF pad conforms to back. This way works very good up to about 25lbs if packed high enough for load lifters to work good.

Thanks, Martin. I prefer stuffing my quilt directly in the pack, but when I get the pack finished I'll try your solution.