pbergwrote a review of Osprey Packs Xenith 105L Backpack on May 9, 2016
Familiarity: I've used it several times
I've had a 65L Osprey Atmos for 5yr that I absolutely love. It's taken me on 8day Summer trips across the Sierra and on 2-3day winter mountaineering trips, and it's performed awesomely. But as I progress to longer, higher-altitude winter mountaineering expeditions, a 65L pack just doesn't cut it anymore.
Enter the Osprey Xenith 105. It has an excellent function:weight ratio. Buckles felt cheap, but I was willing to give it a chance... until I loaded it with 55lb and did a test haul up a local peak. The bag felt incredibly uncomfortable on the lower back.
I've heard complaints from other climbers/hikers about the metal bar that runs horizontally along the bottom of Osprey packs. When loaded, the suspension of the pack causes the metal bar to get pushed into the person's lower back/tailbone and even causes bruising in a few hours time. At first I thought those people just had weird backbones, but I tried it on my Atmos, and I found I can easily replicate this phenomenon in my 65L Osprey pack--if I exceed its maximum 45lb load range. In my mind, though, it makes sense that a 65L pack becomes uncomfortable with a 55lb load because the load is technically outside what the pack is designed to carry. I was okay with that.
On the other hand, the maximum load on this Xenith 105 is 70lb. A 55lb load is 20% under the maximum rating, so I would expect it to carry 55lb comfortably. Unfortunately, no amount of adjusting or packing configuration could make it comfortable for me. I'm not okay with that. A 105L pack shouldn't feel uncomfortable with 55lb. Very disappointed with this pack--I promptly returned it.