The North Face Spire 32

[most stable]

“The hipbelt has enough padding and support to carry a small building,” says one tester who humped this pack on a two-day, 42-miler along the Uwharrie National Recreation Trail in North Carolina. Stability and load transfer are good enough for 50 pounds, and freedom of motion is excellent on tricky terrain.

Key ingredient: tubular X-configured stays that underlay the plastic framesheet. How it works: The top two points of the X are positioned just above each shoulder and they connect directly to the load-lifter straps; the bottoms anchor into the hipbelt next to each of your iliac crests. These precise connections transfer weight, while the X’s junction (located at the center of your back) allows the pack to twist, torque, and pivot—just like your spine. The result is top-notch support and mobility. It also ventilates better than average, thanks to thick, open foam that “literally pumped air across my back,” says one tester.

The Lobo has plenty of loading options—lower and side zippers, plus a wide top opening and a huge shove-it pocket. Smart: A deep head scoop allows for clearance even when the lid is extended with whopper loads. Quibble: Some testers found the wide hipbelt restrictive on high-step climbs.