The Hyperlite Mountain Gear Southwest 55 Backpack is a durable, ultralight backpack made with Dyneema Woven Composite that’s good for thru-hiking and multi-day backpacking trips in rugged terrain. This is the Hyperlite backpack you want to get if you bushwhack and navigate off-trail through dense foliage, desert terrain, or canyon country. The Dyneema Woven Composite used on the Southwest is 10 times more abrasion-resistant than the Dyneema/Polyester Composite that Hyperlite used on earlier models of the Southwest. It’s also a waterproof fabric, so it will prevent your pack from absorbing water and getting heavier in the rain.

If you’re deciding between the Southwest 40 and the Southwest 55, I recommend the 55. The main difference between the two is the length of the extension collar (the part above the shoulders). Being a rolltop pack, this is easily compressed if not needed. With less than an ounce difference between the models, the additional flexibility is worth the extra weight.

• Weight: 29.3 ounces (size medium)
• Gender: Unisex
• Closure: Roll top
• Torso length: Fixed lengths, ranging from 15″ to 21+”
• Pockets: 5, including hipbelt pockets
• Seam-taped: Yes
• Hydration compatible: Yes, port over right shoulder
• Frame: Internal (2 Aluminum Stays)
• Pockets: 5 external, plus main
• Max Load Capacity: 30-35 pounds (Hyperlite claims 40 lbs)
• Materials: Dyneema Woven Composite, Dyneema Hardline (nylon ripstop) pockets
• Volume: 55L w/ 11L of external storage
• Bear canister compatibility: The BV425 and BV450 fit in the bottom, the BV475 fits horizontally in the extension collar, and the BV500 and Garcia only fit vertically.
• Pros: Ultralight, abrasion-resistant, taped seams, wide range of sizes, waterproof fabric
• Cons: Expensive, no load lifters, can’t store a BV500 bear canister horizontally

Close-up of the external side of the new Dyneema Woven Fabric. Looks like a scene out of the Andromeda Strain, doesn’t it?

2025 Model Improvements

Backpack Storage and Organization

The Hyperlite Mountain Gear Southwest 55 Backpack is laid out in a traditional ultralight style with a large main compartment, side water bottle pockets, and a large front pocket. The two sides of the rolltop can be connected to straps and buckles on the sides of the pack or clipped to each other on the top of the pack. I prefer using the side straps because I get better compression in the main compartment, which is helpful when I have a lot of gear or food to carry.

The HMG Southwest 55 has a drybag-style roll top and solid external pockets.

The inside of the main compartment is fully seam-taped, making the interior effectively waterproof since it covers all the thread holes created when sewing the pack. I still recommend lining the inside with a waterproof liner or trash compactor bag, which can keep you warm as an emergency bivy or segregate dirty, wet items such as clothing or rain flies from clean, dry items, etc.

The interior has two frame stay pockets, which hold the pre-bent aluminum stays that form the backpack’s frame and protect your back from sharp objects stored in the interior, like bear canisters. You can remove the stays, but I can’t see why you’d ever want to.

The new Dyneema Woven Composite fabric is quite soft and malleable with the consistency of 1443r Tyvek, so extra care is needed when packing gear in the extension collar.

When packing the Southwest 55, be aware that the pack’s back panel and frame stays end at the top of your shoulders, providing no extra rigidity for gear stored in the extension collar. Heavy items, such as food bags, should be packed towards the bottom of the pack and as close to the back panel as possible to prevent them from shifting or bulging out awkwardly. This is an unexpected consequence of switching to the Dyneema Woven Composite fabric, which is much softer and less rigid than the Dyneema Composite Fabric used in the previous generation of the Southwest. That material was stiffer and much less flexible, allowing for better control of overloads in the extension collar.

When I pack the new Southwest 55, I start by placing my quilt, stuffed in a dry sack, at the bottom of the pack. Then, I stack my food bag on top of it and arrange other heavy items along the back panel as I go. I stuff lighter-weight insulating layers and clothing behind the heavier items to hold them in place, and then put my lightest items in the extension collar (mainly loose clothing and personal effects). I then use the pack’s roll-top to compress the items in the extension collar as tightly as possible, thereby reducing the volume they require, while trying to balance the load on both sides.

The interior of the main compartment is seam taped, making the pack effectively waterproof.

There are five external pockets on the Southwest 55 backpack: two side water bottle pockets, a larger front pocket, and two hip belt pockets. All of the pockets are made of solid 210 denier Dyneema reinforced nylon ripstop (Dyneema Hardline), enabling the pack to be used roughly or in off-trail conditions that would quickly shred most mesh pockets.

The side bottle pockets are quite deep with a diagonal opening, making it easier to reach back and grab a bottle.

The side water bottle pockets are large enough to comfortably fit two 1-liter water bottles together and have drain holes at their base. Water bottles stored in the side pockets are also reachable and replaceable while wearing the pack. I like the deeper side pockets because bottles would pop out of the older Southwest model pockets, especially when venturing off-trail, in places where they’d be hard to recover.

The rear pocket is large enough for me to store all of my wet gear, such as a tarp, tent fly, or wet rain gear, my water filter, and smelly items like a wood stove that I don’t want inside the main compartment.

The bottoms of the black hardline pockets are made with white Dyneema Woven Composite (at least on the white Southwest 55), which lets in some light, making it easier to find items in them. I store my tent stakes, bug dope, Joby tripod, head net, extra soft bottles, trowel/tp kit, a wood stove, my cookpot, and odds and ends in those pockets. Having them backlit makes items much easier to find without having to empty out the entire pocket.

If you don’t need the side compression straps, you can use them to attach bulky gear to the front of the pack.

The hipbelt pockets have waterproof zippers and are large enough to store a smartphone, a few food bars, a Nuun tablet sleeve, or AquaMira bottles. I can open and close the zippers without breaking my stride.

Backpack Attachment and Compression System

The Southwest 55 has two tiers of side compression straps that can be used to attach gear to the outside of the pack. A bottom compression strap runs horizontally outside each water bottle pocket, while the upper strap is oriented at a diagonal to bring the load closer to the wearer’s back for better load-to-hip transfer. Both of these straps are girth hitched to daisy chains running down the sides of the front pocket, so they can be removed.

The shoulder straps have daisy chains that make it easy to add pockets or hang gear from them.

In use, I remove the bottom compression straps over the water bottle pockets because I find they interfere with getting water bottles into the side pockets, or I route the two straps over the front pocket, which can be used to attach bulky gear like snowshoes to the pack. HMG also sells extra webbing straps for this purpose as an add-on, although there’s nothing preventing you from rigging up some cord and cord locks instead.

In addition to the roll top, which provides excellent top compression, there’s a Y strap that runs from the front of the pack (between the shoulders), over the roll top, and attaches to the back of the pack. This strap is great for securing bulky items like a foam pad, rope, or tent body to the top of the pack. You can also lash a bear canister under this strap, but it helps if the pack bag underneath it is very full and tightly packed, so you have a “shelf” to rest it on.

Backpack Frame and Suspension System

Both the Hyperlite Mountain Gear Southwest 55 Backpack and the Southwest 40 Backpack have a lightweight frame system called frame stays instead of a wire perimeter frame or framesheet made with hard plastic. The stays are aluminum rods stored in frame pockets in the main compartment. They come preformed and will fit most people comfortably, but can be easily bent to match your physical characteristics. If you decide to bend them, trace a line on a piece of paper along the side profile of the factory stay, so you can return it to its original shape if you botch this process. It’s easy to botch.

The hipbelt is sewn onto the pack. The framestays terminate behind the seams connecting the hipbelt wings to the lumbar pad.

The frame stays terminate behind the hipbelt and are responsible for transferring the load onto your hips, which are much stronger than your shoulders. The hipbelt on the Southwest is sewn onto the pack bag. Most ultralight backpack manufacturers have stopped doing this, opting instead for a more modular design where different-sized hipbelts can be swapped out and attached with Velcro. I thought Hyperlite had stopped sewing their hipbelts to their packs, so I was surprised to see this on the Southwest. This sewn-on hip belt is one of the main reasons why HMG’s packs carry so well. I think it makes a huge difference in load transfer and control.

The hipbelt of the Southwest 55 is covered with padded mesh, but not overly padded, which is what I prefer, with a beefy front buckle for durability. The shoulder straps also have light padding, with sewn-on daisy chains that make it easy to add accessory pockets, like a shoulder pocket or navigation devices, to the straps.

The top Y strap is handy for carrying bulky gear, like a foam pad, on top of the pack.

Recommendation

The Hyperlite Mountain Gear Southwest 55 Backpack is a robust, multi-day backpack designed for demanding adventures that will outperform most other ultralight-style packs. If you’re rough on backpacks, but still want one that weighs less than two pounds, the Southwest 55 pack probably has your name on it.

Equally, at home on the trail as well as off, the Southwest 55 Backpack has the extra volume required for longer or more technical trips when you need to carry extra gear or clothing. I use mine for long backpacking hikes when I need to carry extra food, shoulder season insulation, or cold weather camping gear that won’t fit in the smaller volume Hyperlite Mountain Gear’s Southwest 40 Backpack.

While effectively waterproof as a benefit of its Dyneema Woven Composite Fabric and seam taping, the value of the HMG Southwest 55 Pack lies in its unique combination of low weight and durability without skimping on functional features. You shouldn’t have to compromise on durability if you want an ultralight backpack. Get one like the Southwest 55 that is designed to last. Nuff said.

Disclosure: Hyperlite Mountain Gear donated a pack for review

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