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Hyperlite Mountain Gear Southwest 55 Backpack Review

Hyperlite Mountain Gear Southwest 55 Backpack Review

The Hyperlite Mountain Gear Southwest 55 Backpack is a durable Dyneema DCF backpack that’s good for thru-hiking and multi-day backpacking trips in rugged terrain. The Southwest 55 is basically the same pack as the smaller volume Hyperlite Mountain Gear Southwest 40 Backpack but with a longer extension collar, so you can stuff more gear inside. This is handy if you need to carry a few more days of food, extra clothing, or more sleep insulation on longer trips or in colder weather.

Specs at a Glance

  • Weight: 32.4 ounces (size large)
  • Gender: Unisex
  • Closure: Roll top
  • Frame: Internal (2 Aluminum Stays)
  • Pockets: 3 external, plus main
  • Max Load Capacity: 40 pounds
  • Materials: 50D and 150D Dyneema DCF and Dyneema Hardline pockets
  • Volume: 55L w/ 9.8L of external storage

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 HMG 3400 Southwest has a dry bag style roll top and solid external pockets
The HMG Southwest 55 has a dry bag style roll top and solid external pockets

The main compartment has a drybag-style closure system which provides excellent top compression for stabilizing your load. The fabric of the DCF pack body is also waterproof and the interior seams of the pack are seam taped, making the pack highly resistant to rain.

Hyperlite Mountain Gear Southwest 55 Backpack


Superlight, Super Durable!

The Hyperlite Mountain Gear Southwest 55 Backpack is a bomber multi-day backpack geared for tough adventures that will rip most other ultralight-style pack to shreds. If you're rough on backpacks, but still want one that only weighs two pounds, the Southwest 55 pack probably has your name on it.

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The main compartment has a mesh hydration pocket and hydration loop if you want to carry a water reservoir/hose inside the main compartment. Since I prefer using water bottles, I use this pocket, which lies in between the two frame stays, to store maps instead.

Interior of main compartment showing mesh hydration pocket and taped seams
Interior of the main compartment contains a mesh hydration pocket, hang loop, and taped seams.

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

The side water bottle pockets are large enough to comfortably fit 1-liter water bottles together in addition to tall skinny items like trekking or tent poles and have drain holes at their base. The bottoms of the pockets are reinforced at the base with a 150 denier DCF to prevent punctures or tearing – an important durability feature. Water bottles stored in the side pockets are also reachable and replaceable while wearing the pack, a must-have.

The rear pocket is large enough to store my hammock tarp, cook pot, wood stove, stake bag, hydration reservoir and sawyer filer, as well as extra rain layers - basically the stuff I don't want in the main compartment because it's wet or smelly.
The rear pocket is large enough to store my hammock tarp w/snakeskins, cook pot, wood stove, stake bag, hydration reservoir, and sawyer filter, as well as extra rain layers – basically the stuff I don’t want in the main compartment because it’s wet or smelly.

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. I also use this pocket to store snacks and extra thermal layers, so I don’t have to open the main compartment during the day when I’m hiking.

The hip belt pockets have waterproof zippers and are large enough to store a small camera, a few food bars, or AquaMira bottles. While I do wish the pockets were positioned a little further forward on the wings of the hip belt so they are more reachable, it’s not a showstopper.

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.

A Y-strap loops over the top of the pack and is useful for securing bulky items like a foam pad or tent body
A Y-strap loops over the top of the pack and is useful for securing bulky items like a foam pad or tent body

In use, I decouple the bottom compression strap over the water bottle pocket because I find it interferes with getting water bottles into the side pockets when I’m wearing the pack (it confuses my hands). Instead, I route the webbing out-of-the-way through additional buckles on the back of the pack which can be used to attach more gear, like snowshoes. HMG 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.

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 rigid wire frame or framesheet made with hard plastic. The stays come preformed but can be easily bent to match your physical characteristics better.

The 3400 has two aluminium frame stays that slot into stay pockets behind the shoulders
The Southwest 55 has two aluminum frame stays that slot into stay pockets behind the shoulders

The frame stays are two aluminum rods that slot into frame stay pockets on the inside of the main compartment and terminate inside the hip belt. The stays keep the back panel behind your shoulders rigid so it won’t collapse on itself. They also help transfer some of the pack weight off your shoulders and onto your hips, since the bottom of the stays terminates inside the Southwest 55 hip belt, which is sewn directly onto all of HMG’s packs. The sewn-on hip belt is one of the main reasons why HMG’s packs carry so well. Shop around. Very few ultralight pack manufacturers have a hip belt that is so tightly coupled with the pack body. It makes a huge difference.

The hip belt 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 my camera pocket (shown), or navigation devices to the straps.

Daisy chains sewn on the front of the shoulder pads make it easy to attach exra pockets or navigation instruments
Daisy chains sewn on the front of the shoulder pads make it easy to attach extra pockets or navigation instruments

When packing the Southwest 55, you need to be cognizant of the fact that the pack’s back panel and frame stays end at the top of your shoulders and do not provide extra rigidity for gear stored in the extension collar. Heavy items, like food bags, should be packed towards the bottom of the pack and as close to the back panel as possible. This is doubly important because HMG does not put load lifters on their backpacks because they don’t have full frames (load lifters on frameless packs have marginal utility), and there’s no way to tilt your load forward if you’ve packed it so it pulls your center of gravity backward.

When I pack the Southwest 55, I put my sleeping bag stuffed in a dry sack at the bottom of the pack and then stack my food bag on top of it, stacking my hammock and other heavy items up 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 clothing and personal effects). I then use the pack’s roll-top to compress the items in the extension collar and shrink the volume they require. This weight and volume distribution provides the best load control since heavy items are located near my hips and there’s a direct transfer of kinetic energy from my core to items located just above the small of my back.

Cold and frosty morning on the Maryland AT with the Hyperlight Mountain Gear 3400 Southwest Backpack
Cold and frosty morning on the Maryland Appalachian Trail with the Hyperlite Mountain Gear Southwest 55 Backpack


The Hyperlite Mountain Gear Southwest 55 Backpack is a bomber multi-day backpack geared for tough adventures that will rip most other ultralight-style packs to shreds. If you’re rough on backpacks, but still want one that only weighs 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 section hikes on the Appalachian Trail when I need to carry extra food, shoulder season insulation, or cold weather hammocking gear that won’t fit in the smaller volume Hyperlite Mountain Gear’s Southwest 40 Backpack that I use for off-trail hiking and weekend backcountry fishing trips in New Hampshire’s White Mountains.

While highly water-resistant as a benefit of its Dyneema Composite Fabric, the value of the HMG Southwest 55 Pack lies in its unique combination of low weight and durability without skimping on functional features. You don’t need to compromise on durability if you want a lightweight backpack. A backpack is a big gear purchase. Get one that is designed to last. Nuff said.

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  • Taped seams and needle holes make the pack nearly waterproof
  • White color makes it easy to find gear inside pack
  • Roll top closure and side straps provide good compression
  • Side water bottles are reachable and replaceable while wearing the pack
  • Bomber tough against puncture or abrasion by aggressive vegetation
  • Side and front external pocket have reinforced bottoms and drain holes
  • Fantastic load to hip transfer
  • Daisy chains sewn into shoulder straps make it easy to attach accessories
  • Good range of sizes available for people with short torsos, including women


  • More expensive
  • White color is quickly discolored by dirt and grime
  • Center ice axe loop is awkward to use; no shaft attachment provided

See Hyperlite Mountain Gear for complete product specifications.

Disclosure: Philip Werner purchased this product with his own funds. 

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  1. That’s what I’m leaning towards. Thanks. When it rains, does the water drain out of the pocket holes at the bottom well? How do you rig your tent if you need to dry it out on the outside of your pack? Will it still get dry in the pocket?

  2. I’m thinking about getting the Granite Gear ‘Crown2 60’ for Section Hiking & the ‘HMG 4400 Windrider 70L’ for my 1st AT Thru-Hike. I am drawn to Hyperlite’s design & overall aesthetic but this review reassures me that function & utility are not spared.

  3. As much as you (& others) like this pack, it’s very tempting to buy it from REI & test it out on a couple trips! Regardless of the lack of load lifters. I’m looking, as you know, at the SO Flight, Hanchor Marl, as well as this – but with REI’s 1 year return (& I called them to make sure I wouldn’t be abusing their policy) it a great way to see if the 3400 fits & works!

  4. If you could have only one, (more) to lighten your load & you already have a big Gregory Baltoro 75, which would it be with a 15 lb base weight, the need to carry a BV450 or 500, & mostly 2 – 4 night trips, HMG, Seek Outside Flight, Hanchor Marl (or something else)? I know I keep asking!

    Also, note – seems REI has reduced its line of HMG to Windrider 2400s & 4400s (no SW 3400).

    Thanks Philip!

  5. Thanks Philip. I’ve got the hiking part down, just not the lighter gear yet. But I appreciate your response.

  6. Seems like HMG is selling themselves short with their naming conventions. I would have expected a 3400 model to pack 34L, not 55L.

    For planning purposes, please note that they currently have a backlog. The web site currently predicts that it it will take packs four weeks to ship.

  7. Looking at several packs, 3400, SWD although lead times are 6 months and Granite gear. Like idea of custom tall pocket on SWD for tent placement. Where are you packing it with SWD? Obviously inside, would it fit outside?

  8. Michael Brownfield

    Hi Phillip,
    I really like this pack but have heard several times that HMG packs lose their water repellant quality with extended use. I am not sure if it is a case of abuse of the equipment, the DCF fabric itself, abrasion, or if it is just talk. It could be the latter as I have spoken with other long distance backpackers who have not had any problem with leaking.

    Have you experienced this with your packs or encountered other hikers with long term use that claim a loss of waterproofness.
    Thank you,

    • The DCF does break down with a LOT of use, from the constant folding and unfolding. But I’ve never noticed water actually leaking in except when I’ve torn a hole in the bottom. ULA’s new circuits are made with seam-taped XPac, which is almost never seam-taped by other manufacturers. That about the only practical alternative to DCF that I know of. I have one of the XPac ULA Circuits, but I’m still on the fence on whether I like the material.
      It’s really heavy XPac.

  9. Just ordered my 3400 Southwest from REI!! Ill be using it for thru hiking and packrafting. Was contemplating the 4400 from a friends advise that packrafts and clilmbs. After seeing photos of the 3400 on you and how bit it is, I could see that the 3400 would be plenty big for my uses. Thanks for the great and honest review!!

  10. I have 2 questions about the pack. I tried on my friend’s pack (same one except with mesh pockets) that she’s had for a few years. I couldn’t reach my water bottles from the water bottle pockets! I was really surprised. Has the design changed to make them easier to reach? I also noticed the hip belt pockets were set further back. In addition, the zipper pull was on the opposite side of the hip belt pockets than I’d prefer – i.e. on the end closer to the water bottle pockets, as opposed to the end closer to your hip belt buckle. Is it still that way? It just feels a bit annoying having to reach back there to unzip them.

    • They enlarged the hip belt pockets a few years ago, but I doubt they changed the position or access to the side pockets. They like to boast about any changes they make to the packs based on customer feedback….and they haven’t boasted about anything since they made the hip belt pockets more useful. :-)

  11. Hi Philip, thanks for the review! I’m in the market for a new UL pack to use for thru-hiking and this one wasn’t on my list until your post. Hyperlite mentions that the 3400 pack is good to 40 pounds which seems heavy. I’m curious what your opinion of this pack if it were loaded to 40 pounds?

    • It can carry that much without the frame stays buckling but you’ll probably suffer for it since the hip belt isn’t very padded. It will really depend on how well the torso length and hip belt will fits you. 30 lbs no problem but when you start inching up towards 40, that can get a little ungainly with any ultralight backpack dependning on the hip belt.

  12. How do you think that this would fare doing some winter day hikes i.e. attaching things like snowshoes and the like on the back and sides?

    • It’s pretty awful. Get a granite gear crown 3. Infinitely better. I’d suggest the GG crown 2 38, which is what I use as a winter pack in the whites, but its not made anymore.

  13. Thank you for the wonderful review. In Japan, ‘Hyperlite Mountain Gear’ is very popular and often hard to obtain. Do you happen to know any e-commerce sites, other than the official website, that ship to Japan?

  14. I love the pack, but I hate the obnoxious bright white HMG logo sewed to the back of my solid black Southwest 55.

    Problem solved in three minutes with a black Sharpie marker.

    (Sorry, HMG.)

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