Comparing pack suspensions / fitting Gregory vs Osprey

I no longer use free weights for training hikes because they tend to shift and unbalance the pack. I have found 25 lb bags of cat litter have the right volume and density for a consistent feeling load. This loading method limits the variables when testing the load carrying comfort of a pack.

Take the time to pack them both like you really would. With the hip belts on both of those packs all the straps should have to do is keep the pack from falling backwards. You either have them packed really poorly, or they don't fit at all.

I packed both packs reasonably well. Tent on the bottom straps, sleeping bag on the bottom, cookpot + stove+fuel, 1/2 gallon apple juice (simulating 2L of hydration bladder), Klymit sleeping pad, a couple shirts + 7.5 lbs of weights to simulate food, toiletries, camera, etc. Looking at the frames of the packs, the Osprey goes around the parameter of the pack and is wider at the bottom, where the Gregory is an X. I feel when unbuckling the Osprey hip belt, the weight is shifted more on my shoulders, where unbuckling the Gregory belt doesn't seem to do much.

"I have a 17" torso, so I'm a size small in both." I'd bet you would do better with a medium. 17 may be at the upper limit of the advertised range for small, but that claim is simply wrong.

I sling packs for REI part time. We send a ton of Gregory and Osprey packs out the door. As noted above, if you are on the cusp between sizes, pretty much always the larger size will fit better. If you are long-waisted and skinny, you may find that for the torso length you need, the hipbelt is too big. Some larger-volume models in both brands (not Z55) have removable hipbelts and you can switch them out. This year both Gregory and Osprey seem to be backing away from that plan in favor of making the hipbelts more adjustable instead. (It is truly a pain to go fish the correct hipbelt from the boxes way on the top shelf in the backstock closet.) But the most important consideration is, not every pack model can be adjusted to fit everyone comfortably. Kind of like shoes that way. A brand/model may just not be shaped in a good way for you. No amount of adjustment will fix that. You should just try something different. Especially with respect to Gregory packs. In my experience, people either say (kind of like you did) "what's that poking my back?" or else the say "Oh my gosh, I'm home!" (Not wanting to create thread-drift but I guess I had better point out the following before someone else brings it up: Yes, I am forever gently encouraging my customers to lighten up their loads and go with smaller and lighter packs. Many are appreciative. I even refer folks to brands REI doesn't carry (many smaller companies couldn't supply REI in any case) when it seems appropriate. But many, many folks are not especially responsive to advice to lighten up. They just need to learn from their own experience.) Mina