Gregory Diablo Backpack


Gregory Mountain Products’ latest backpacks have a suspension system the company touts as “mimicking the body as it moves.” Built for trail running, cycling, and pursuits like adventure racing, ultra running, and orienteering, the Bio-sync suspension system is used on eight new packs released this spring.

The secret to Bio-sync is in the packs’ elasticized attachment points, which give stretch and flex via dual dynamic straps connected where the waist belt and harness interface to the backpack. The stretch, in theory, is made so that a loaded pack will “move with and mimic its wearer’s body during activity.”

I tested the Diablo, the smallest pack in the line at just 6 liters of capacity. When empty, the Diablo weighed 1 pound on my scale. Loaded, it can tote a day’s worth of hiking essentials — compass, jackknife, map, matches, an extra top, some food — if you go light. Plus, there’s space for a mid-size hydration reservoir. (My CamelBak 100-ounce reservoir had trouble fitting in the pack at its full capacity.)

Gregory Diablo Backpack

The Diablo costs $59, and there are several nice touches, including internal mesh separator pockets and zippered pouches on the waist belt for quick-grab food or small gear. There’s a “tube management system,” which is made so that after a drink the tube from your hydration reservoir will snap back on the shoulder harness, Velcro-ing in place.

As for the Bio-sync suspension, it was almost unnoticeable on the Diablo. The pack is so small that it does not take loads heavy enough for anything more than the subtle engagement of the suspension system.

Bio-sync likely is more noticeable on the larger backpacks in the line, which haul more gear and are more of a burden when you move.

All that said, the Diablo ( is a fine pack for running and cycling. I tested it for a month, running seven miles one evening on a trail with water, an extra layer, and some energy food. The pack bounced some, but for the most part sat comfortably as I jumped rocks, ran the hills, and paced ahead alone in the woods.

—Stephen Regenold writes a daily blog on outdoors gear at

Stephen Regenold

Stephen Regenold is Founder of GearJunkie, which he launched as a nationally-syndicated newspaper column in 2002. As a journalist and writer, Regenold has covered the outdoors industry for two decades, including as a correspondent for the New York Times. A father of five, Regenold and his wife live in Minneapolis.