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Hyperlite Mountain Gear Unbound 40 Review

For those seeking a pack to support their cross-country thru-hikes with tons of external storage space, excellent weather resistance, and famous durability
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Hyperlite Mountain Gear Unbound 40 Review
Credit: Justin Simoni
Price:  $369 List
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Manufacturer:   Hyperlite Mountain Gear
By Justin Simoni ⋅ Review Editor  ⋅  Jun 5, 2024
85
OVERALL
SCORE


RANKED
#3 of 19
  • Comfort - 40% 9.0
  • Ease of Use - 25% 9.0
  • Weight-to-Volume Ratio - 20% 7.0
  • Adjustability - 15% 8.0

Our Verdict

The Hyperlite Mountain Gear Unbound 40 yearns to be taken out on the trail for days and weeks at a time, bringing along with it superior comfort, durability, and tons of storage and organizational options. Comfort comes from just enough foam padding embedded in the back of the pack and the single-shaped metal stay, adding welcome rigidity and helping transfer pack load onto the well-designed hip belt. The durability of this pack is due to the use of Dyneema Composite Materials with a thick, 150-denier face fabric that'll take a ton of trail abuse before protesting. Center, side, hip belt, and a unique to our lineup bottom stash pocket equates to 15 additional liters of storage to complement the 34L inside, making excellent tools to keep you highly organized so you know where to quickly find some snacks when you're dying of hunger or just where to grab your rain jacket when the heavens open up. The Unbound 40 will most likely be attractive to all but the most extreme gram counters as all these pockets and use of thicker, more durable material won't win an award for most svelte pack on the trail, but we think the tradeoff is worth it. We found this pack handles heavier loads extraordinarily well, even without featuring load lifters.
REASONS TO BUY
Tons of external storage with different pockets
Durable and water-resistant DCF pack material
Comfortable yet minimal padding and vertical stay
Removable hip belt
REASONS TO AVOID
Durability comes at a cost of additional weight
Lacks load lifters

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Price $369 List$315 List$275 List$399.95 at Backcountry
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Bottom Line An excellent lightweight pack with a multitude of external storage space options to complement its main pack compartmentAs an all-around great pack, it can carry large and light loads with ease, has plenty of external storage options, and is super comfortableOne of our favorites that scores highly in all metrics, is comfortable and versatile, and has just enough features for a reasonable costA running vest inspired backpack made with lightweight yet extremely tough fabric, perfect for your next weekend trip or to cross the countryThis ultralight option doesn't leave out all the fantastic features found in packs at higher weight classes
Rating Categories Hyperlite Mountain... Gossamer Gear Marip... Gossamer Gear Goril... Black Diamond Beta... Osprey Exos Pro 55
Comfort (40%)
9.0
10.0
10.0
9.0
9.0
Ease of Use (25%)
9.0
10.0
9.0
8.0
9.0
Weight-to-Volume Ratio (20%)
7.0
8.0
5.0
7.0
5.0
Adjustability (15%)
8.0
8.0
8.0
9.0
7.0
Specs Hyperlite Mountain... Gossamer Gear Marip... Gossamer Gear Goril... Black Diamond Beta... Osprey Exos Pro 55
Measured weight 34.6 oz 32.6 oz 31.1 oz 31.68 33.2 oz
Weight per liter (full pack) 0.87 oz/L 0.54 oz/L 0.62 oz/L 0.70 oz/L 0.60 oz/L
Advertised volume 40 L 60 L 50 L 45 L 55 L
Stripped weight 26.0 oz 18.0 oz 17.2 oz 19.0 oz 30.4 oz
Measured volume (main compartment) 35 L 42 L 39 L 40 L 33 L
Organization Compartments Side pockets, center pocket, dual zippered pockets on hip belt, bottom stash pocket, main compartment Lid, side pockets, center pocket, dual zippered pockets on hip belt, main compartment Lid, side pockets, center pocket, dual zippered pockets on hip belt, main compartment Side pockets, center pocket, dual zippered pockets on hip belt, main compartment Lid, mesh side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Hydration compatible No Yes Yes Yes Yes
Single side pocket 700ml Smartwater capacity 5 5 3 5 5
Single hip belt pocket capacity 6 Clif Bars 5 Clif Bars 5 Clif Bars 5 Clif Bars 4 Clif Bars
Able to strip off frame and hip belt Yes Yes Yes Yes No
Whistle on sternum strap Yes Yes Yes No Yes
BearVault BV500 compatibility Ok Good Ok Good Good
Sizes Available Torso: S, M, L, Tall
Hip Belt: M (S & L sold separately)
Torso: S, M, L
Hip Belt: S/M curved (M/L curved and S, M, and L straight sold separately)
Torso: S, M, L
Hip Belt: S/M curved (M/L curved and S, M, and L straight sold separately)
Torso: XS, S, M, L Torso: S/M, L/XL
Frame type 1 removable aluminum stay, embedded, non-removable foam pad SitLight foam pad / removable stay SitLight foam pad / removable stay 2 removable stays, thin foam padding 3.5 mm powder-coated LightWire frame
Fabric 150 D DCH fabric, Dyneema Stretch Mesh, Hardline with Dyneema 100D & 200D Robic nylon 100D & 70D Robic nylon Ultra 200, Ultra 400, 4-way stretch mesh, 100d nylon 4mm Ripstop NanoFly: 100D nylon x 200D UHMWPE ripstop

Our Analysis and Test Results

The Hyperlight Mountain Gear Unbound 40 is an ultralight wonder that stands out as one of our favorite packs to take on trips that span days to many weeks. We adore all the well-designed external pockets that securely keep gear we didn't want to pack inside its cavernous main compartment safe.

Performance Comparison


hyperlite mountain gear unbound 40 - this pack is an excellent choice for longer excursions with its...
This pack is an excellent choice for longer excursions with its comfort, durability, and adequate storage.
Credit: Justin Simoni

Comfort


Comfort is rarely king in ultralight packs, which usually make compromises on their quest for a lower scale number, but we found the comfort of the Hyperlite Mountain Gear Unbound 40 quite princely. Back, lumbar, hip belt, and shoulder straps all have just the right amount of embedded foam padding to ease the strain from our heavy loadouts. The interior-shaped metal stay facilitates the delivery of a pack load off already strained shoulders towards the hip belt, where it can be born more easily.


Several features can be found on the Unbound 40 to dial in the fit. J-shaped shoulder straps allow you to cinch down a load tightly to your body, and the single sternum strap can be easily adjusted up and down via the ribbon of bar-tacked webbing on each strap. The hip belt can be independently adjusted from each side by the hip pockets to really dial in the load distribution. Minimal elastic cinches on the side of the pack can be employed to flatten the main compartment and help minimize bouncing and jostling for less-than-full loads. There are no load lifters on the top side of the pack, but the pack's design has the rolltop end at the shoulders, so these wouldn't be effective. We didn't miss them ourselves, and we are comfortable with 40+lb loads, but if you rely on these, note they're not available on the Unbound 40.

hyperlite mountain gear unbound 40 - there's a fair amount of padding on the hip belt and lumbar region...
There's a fair amount of padding on the hip belt and lumbar region. The belt is removable if you would like to save weight hiking without it or swap it out for a different size (sold separately).
Credit: Justin Simoni

Ease of Use


Employing the thick, tough, 150-denier-faced DCF in the black version of the Hyperlite Mountain Gear Unbound 40 helps the roll top stay open without flopping around, making loading up the main compartment of this pack easy. Even when we make some interesting shopping choices at the grocers, the larger-than-most center and side pockets do a great job of swallowing up our gastronomic provisions.


Lashing a bear canister using the top y-strap works well and is secure. The approx. width of the Unbound 40 is 14 inches, so a smaller canister like our BV 450 will fit inside lengthwise, but a taller canister may not.

A bear canister can be fitted to the top of the bag's roll top using...
A bear canister can be fitted to the top of the bag's roll top using the included y-style strap.
A bear canister can be carried either empty outside the pack or while filled with your food inside.

We found the center pocket's secondary bottom flap and opening really useful for grabbing gear like sunscreen that naturally finds its way to the bottom.

hyperlite mountain gear unbound 40 - the hyperlite mountain gear unbound 40 has a lower center pocket...
The Hyperlite Mountain Gear Unbound 40 has a lower center pocket that connects up with the main center pocket. You can use it to store small items or to grab items from the bottom of the main center pocket.
Credit: Justin Simoni

We also really fell in love with the bottom stash pocket, which can be used as yet another place to put often used gear. The trash port embedded in its side also helps us organize as we go through all our snack packs. The side, bottom, and hip pockets can also be easily accessed by us one-handed — something we just can't say worked quite as well for all the packs we've tested. That usability really compounds after days/weeks on the trail.

The generous side pockets are designed in a way to be reachable to grab gear like a water bottle easily and on the go.
Credit: Justin Simoni

Weight-to-Volume Ratio


We weighed up the Hyperlite Mountain Gear Unbound 40 at 34.6 oz/981 grams with all the accoutrements attached, and 26.0 oz/737 grams stripped of its hip belt, back stay, and optional cinch straps.


Weight per liter is around 0.87 oz/L, making this one of the heavier packs for the volume it holds, but certainly still quite featherweight, all things considered.

hyperlite mountain gear unbound 40 - the unbound 40 swallows gear! we measured the main compartment to be...
The Unbound 40 swallows gear! We measured the main compartment to be at least 34 liters. All the gear seen to the right fits into that main compartment. This includes a complete sleep system, clothes for days, camping shoes, electronics, toiletries, and a 4 Liter water flask. More room is available in the center and side pockets, as well as the bottom stash pocket.
Credit: Justin Simoni

The Unbound 40 is one of the more feature-rich packs in HMG's lineup. Much of what we adore about this pack: the large center and side pockets, the comfy back paneling, and the use of a very tough DCF variant do all add up to the heftier total weight.

Each side pocket can squeeze in up to 5 one-liter smartwater bottles.
Each side pocket can squeeze in up to 5 one-liter smartwater bottles.
The stretchy yet durable center pocket has enough volume for four...
The stretchy yet durable center pocket has enough volume for four, one liter smartwater bottles.
The bottom stash pocket can fit three, one-liter smartwater bottles.
The bottom stash pocket can fit three, one-liter smartwater bottles.
External capacity for the center, side, bottom, and hip belt pockets clocks in around 15 liters!

If the weight of your pack is the most important attribute you're looking to minimize, the Unbound 40 won't be your best choice.

We measured the Hyperlite Mountain Gear Unbound 40 as having approx. 34L of internal volume in its main compartment.
Credit: Justin Simoni

Adjustability


The Hyperlite Mountain Gear Unbound 40 is reasonably modular. If you're carrying a lighter load for just an overnighter or want to go on a day hike, you can drop a few ounces by taking off the hip belt. The roll top is extremely generous and, for carrying smaller loads, can be rolled all the way down to the top of the shoulder straps, and elastic side cinches can help with any jostling. The pack sizes offered are Small, Medium, Large, and Tall.


The Unbound 40 comes with sewn-on shoulder straps, so if the J-shaped straps don't work or are too long/short, there aren't any options to easily customize them, nor are there other strap designs available. The hip belt size is also tied to the torso length, so a Medium pack will also get a Medium hip belt. Specific hip belts to the Unbound 40 are available to order separately, as is a hip belt extender strap — both at a reasonable price.

hyperlite mountain gear unbound 40 - the hip belt, back stay and the two side cinch straps can be removed...
The hip belt, back stay and the two side cinch straps can be removed from the Hyperlite Mountain Gear Unbound 40 if you would like to save several ounces when hiking in with a lighter carry.
Credit: Justin Simoni

Should You Buy the Hyperlite Mountain Gear Unbound 40?


If you're planning on a classic, long-distance backpacking route like the Appalachian Trail, Continental Divide Trail, Colorado Trail, Pacific Crest Trail — or something else of a similar ilk, the Hyperlite Mountain Gear Unbound 40 makes more than a worthy trail buddy you won't try to drop a few days in. Its very impressive durability and comfort, and all those pockets will help you enjoy your time moving through whichever wide-open, impressionistic painting-like landscapes you may find yourself in on a calm, cool summer day.

The bottom stash pocket securely holds more items close at hand, without needing to open the main compartment.
Credit: Justin Simoni

What Other Ultralight Backpacks Should You Consider?


If comfort is important to you, the Gossamer Gear Gorilla 50 is another excellently designed pack with comfort in mind. The REI Co-op Flash Air 50 is another rolltop bag similar to the Unbound 40, which also has good padding for the back and hip belts to take on some heavier loads. It does feature load lifters, which the Unbound 40 lacks.

hyperlite mountain gear unbound 40 - don't forget to check in with friends and family! four extremely low...
Don't forget to check in with friends and family! Four extremely low profile daisy chains are found on the outside of the center pocket, perfect for clipping on accessories like a satellite tracker.
Credit: Justin Simoni

Justin Simoni