tThe backpack that practically defined the modern ultralight backpack just got a major update. The Hyperlite Mountain Gear Southwest, long revered by hikers for its bombproof simplicity, has been redesigned with Dyneema Woven Composite 3.9, a next-generation fabric that’s stronger, more weather-resistant, and quieter than ever.
For nearly a decade, the Southwest has been HMG’s flagship, a workhorse capable of transporting equipment from the AT to the PCT with almost mythical reliability. This latest version pays homage to that heritage while modernizing the design for the next generation of long-distance hikers.
I tested the new Southwest 55 throughout Baxter State Park this summer, leading multiple trips through Katahdin and through Maine’s famously unforgiving countryside to see if this revamped version still lives up to its iconic reputation.
Hyperlite Mountain Gear Southwest 55 At a glance
Recommended RRP: $399
Weight: 29.3 ounces | 830 grams (Size M)
Materials: Dyneema 3.9 Woven Compound
Internal volume: 40L, 55L, 70L (I reviewed the 55L)
External volume: 11.5 L (40 L version), 13.4 L (55 L version), 16 L (70 L version)
Home country: Mexico
Circumstances of use
I used the Southwest 55 on guided backpacking trips throughout Baxter State Park, from multi-night outings to climbs to the summit of Katahdin. Conditions ranged from steady downpours to dry, granite-covered trails, providing an ideal testing ground for both comfort and durability.
Hyperlite Mountain Gear Southwest Features
Dyneema 3.9 Woven Compound: Next Level Durability
The biggest change, and the star of this update, is HMG’s use of Dyneema Woven Composite 3.9, a fully woven Dyneema fabric that replaces the older DCH hybrid materials. It’s stronger, more abrasion resistant and quieter in use, with a clean matte finish that feels technical and refined.
This material is significantly stronger than traditional DCF while retaining excellent water resistance. It’s built to withstand granite, blowdowns, and years of hard miles with nary a scratch. This material has already been used in their Northrim backpack, made for canyoning, and is now being introduced in other models.
Refined structure and transportation
HMG improved the design of the back panel and internal aluminum support system, giving the backpack a more natural contour that adapts to the body. Weight transfer to the hips feels smoother, and the improved shoulder strap and hip belt padding strike a great balance between structure and comfort.
Smarter storage
The new Southwest maintains its classic, no-nonsense design, but refines the details. Three solid Dyneema fabric pockets allow for excellent storage and unmatched durability, while dual side bottle pockets and an oversized front pocket offer versatile organization. A roll-top closure with side compression straps protects from the weather and keeps cargo tight. The result is a sleek, rugged system built for tough adventures and lesser pack-destroying routes (e.g. high routes).
Weather resistance
The new Dyneema Woven Composite fabric naturally repels water and HMG’s taped seams enhance that protection. After several days of hiking in steady rain, my contents remained completely dry without a liner, a rarity even among DCF backpacks, which claim to be waterproof but eventually get wet.
Hyperlite Mountain Gear Southwest 55 Pros
Indestructible fabric
The new Dyneema fabric feels like an evolution of everything that made HMG famous. It is stiffer, quieter and much more resistant to abrasion than previous generations. It’s the closest thing to a “buy once, cry once” backpack fabric that exists in the backpacking industry.
Safe transportation under load
With improved shoulder straps and a refined hipbelt, the Southwest comfortably carries up to its 40-pound limit. I typically carried between 30 and 35 pounds (including group gear and first aid kits) and found the ride to be exceptionally stable, even over rocks and steep talus fields.
Thoughtful design tweaks
New shoulder straps and a stitched back panel give the pack a more secure, close-fitting fit that feels balanced and stays comfortable over long miles. I noticed better weight distribution right away, along with less shifting when moving fast or climbing.
The exterior pockets also received a thoughtful redesign: they’re deeper, easier to reach thanks to lower rear edges, and hold bottles and loose gear more securely. Even small details, like how an ice ax or trekking pole sits, feel more fine-tuned. Nothing flashy, just smart, functional updates that make the backpack even sharper.
Hyperlite Mountain Gear Southwest 55 Cons
High cost of durability
At $399, the Southwest 55 isn’t cheap and the new fabric pushes that price even higher. For those new to the world of ultralight backpacking, it’s a significant investment. But given its longevity, it’s arguably more economical in the long run than replacing lesser packages every couple of seasons.
Limited adjustability
Like the original, the new Southwest uses fixed lengths for the torso and hip belts, meaning fit is crucial. There is little room for micro-adjustments once you’ve chosen a size.
Final thoughts
The updated Southwest package isn’t just a facelift; It represents a full-fledged material evolution. With the switch to Dyneema Woven Composite 3.9, HMG has created a backpack that is stronger, more refined and still true to its minimalist roots.
After weeks of guidance and much deliberate abuse, mine still looks almost new: no scuffs, no scuffs, no complaints. It has officially become my go-to backpack for both personal travel and professional use.
If you want a backpack that can withstand thousands of miles of abuse, keep your gear dry even before full submersion, and look good doing it, this new Southwest is hard to beat.
Buy Hyperlite Mountain Gear Southwest
Comparable packages
ULA circuit
Suggested retail price: $299
Weight: 38.5 ounces
Maximum capacity/load: 68 L / 35 lb
Gossamer Gear Butterfly 60
Suggested retail price: $315
Weight: 34.2 ounces
Maximum capacity/load: 60 L / 35 lb
Zpacks Arco Haul Ultra 60L
Suggested retail price: $399
Weight: 22 ounces
Maximum capacity/load: 40 lbs.
The Hyperlite Mountain Gear Southwest was donated for review purposes.
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