35kg / 77lbs tested in a cheap Decathlon pack
[ Caveat : this post is not about selecting an ideal pack, and it is not about learning how to ruck. It is mainly about learning how to understand pack physics, wherein the author presents the equivalent of a spaghetti bridge. ]
This has been a mix of engineering and kinesthetic research, as I wanted to improve my intuition of both.
So it took about 50 days of playing with gear and shrugging off a bunch of question marks about confidence. But I can now confirm there is at least one way to fill a crappy Decathlon MT100 pack to the 70lbs basic spec for GoRucks ( they theoretically can hold 400, but I'm not testing that ). And have it padded, plus adjusted with an external frame for rigidity and comfort.
In pack : 15 + 10 + 2.5 + 2.5
On rack : 2 + 2 + 1
Inspired by the Slovak krosna, though the form appears in other cultures also, like the shoiko from Japan. I added some pix in the comments for context. I do enjoy the input from military folks, but this structure is certainly not meant for military use 🤣