PUBLISHED APR 18, 2024
COREY BUHAY
The Radix 57 backpack doesn’t just look sexy with its sleek monochrome fabric and tantalizing, full-length side zipper. It also delivers best-in-class comfort, load carry, and gear access, all in a sub-four-pound package—about a pound less than many other packs capable of carrying similar loads.
Editors’ Choice
Mystery Ranch Radix 57
Weight: 3.8 lbs
Size: M’s S-XL and W’s XS-L
Pros and Cons
- Superior load carry
- carrying comfort
- Tiny hydration sleeve
The Radix’s secret: shaving weight by using space-age materials—not skimping on suspension. Mystery Ranch kept its industry-famous weight distribution system in place, but swapped the typical thick nylons for more modern fabrics and upgraded the frame aluminum and geometry.
On the outside, a strong-but-gossamer 100-denier Robic nylon is reinforced with a grid of ultra-high molecular-weight polyethylene (UHMWPE), a uniquely strong and waterproof thread. While the pack isn’t seam-taped—and therefore isn’t waterproof—the UHMWPE and DWR-coated Robic nylon makes it highly water-resistant as well as abrasion-resistant. “I’ve squeezed under large blow-downs and past grabby bushes and trees,” reports Washington-based tester Matt Wise. “The pack hasn’t been phased.” Outside’s Senior Gear Editor, Benjamin Tepler, took the bag on North Carolina’s Art Loeb trail and spent three days smashing through soggy, overgrown thickets. All his gear stayed dry and the pack came out the other side without so much as a pinhole.
The real magic, however, is on the inside of the pack. Within the foam-padded back panel, you’ll find a 7000-series aluminum frame. That’s aerospace-grade—the strongest aluminum alloy available on the commercial market. The frame is contoured to the spine to keep loads close to the back, reducing pack sway in technical terrain. The frame’s lightbulb shape transfers loads to the center of the hipbelt, keeping the weight on your hips, not on your shoulders. But the lightbulb shape does more than just funnel load forces inward; it’s also uniquely designed to provide both vertical stability and torsional flex. Our testers found it supported a natural gait, even while picking their way down rocks and roots on steep Appalachian descents.
Unlike some other lightweight packs, the Radix doesn’t opt for sturdiness over comfort. Broad, plush hipbelt wings cup the iliac crests, eliminating rubbing. Load lifters and a cushy lower lumbar pad let testers heft up to 50 pounds without next-day soreness. (While there are other UHMWPE packs that can carry up to 60 or 70 pounds, these often cost up to twice as much.) “It’s the best pack I’ve tested yet,” says Wise. “It’s become my go-to for three- to four-day trips.”
And the Radix has the capacity to handle lightweight trips up to a week long. A cavernous dorsal pocket holds a day’s food and extra layers, and large lateral pockets can each fit two water bottles, a two-person tent, or rain gear. Better yet: both lateral pockets are angled to remain accessible while hiking. The rest of the pack’s organization is equally outstanding. An off-center, full-length zipper flays the bag open nearly flat, making gear access and camp setup a breeze. The waist pockets each fit a phone or snacks, and a roomy toplid accommodates a hat, gloves, and first aid. The Radix also sports dual ice axe loops and trekking pole bungees, both of which are easy to use, even with gloves on.
More good news for weight-conscious hikers: the toplid, compression straps, and frame are all removable, bringing the total weight down to just 3 pounds. Few packs can serve as a both light day pack and an extended expedition rucksack, but the Radix 57’s marriage of hardcore support and lightweight fabrics makes it the rare exception.
