[Review at my own expense] Hyperlite Mountain Gear UNBOUND 40: A top-tier ultralight and durable backpack with dramatically improved storage and customizability

As a jack-of-all-trades hiker who enjoys a wide variety of mountain outdoor activities, from hiking to fastpacking and river climbing, if I could only choose one backpack, the first thing that comes to mind would be the North American ultra-lightweight outdoor brand Hyperlite Mountain Gear (hereinafter referred to as HMG).

I have many favorite backpack brands, but theirs are one of a kind: simple, ultra-lightweight, stripped-down, yet sturdy and stable. They're perfectly suited to the rugged and varied mountain activities of Japan, from light hiking to waterfall shower climbs and steep bushwhacking. Their simple yet sophisticated design and ability to hit every spot is what makes them so appealing

HMG has finally released a new hiking backpack this season. It incorporates the latest UL hiking trends and is said to be a groundbreaking evolution that will take care of all your needs! You just have to try it out

So, I've been carrying , the UNBOUND 40,

Key Features of Hyperlite Mountain Gear UNBOUND 40

This hiking backpack is made from lightweight, durable, and waterproof DCH (Dyneema Composite Hybrid) material. The back features a single vertical aluminum stay and foam padding, providing excellent load-bearing capacity despite its light weight. It also features large side pockets, front and bottom stretch mesh pockets, and daisy chains throughout for practical external storage. It's perfect for a wide range of activities, from long-distance, nonstop FKT-style thru-hiking to fastpacking, regular hiking, and even off-trail activities like stream climbing

Favorite points

• Dyneema stretch mesh front and bottom pockets
• Large capacity side and hip pockets
• A wide variety of highly customizable daisy chains
• Lightweight, durable, and waterproof Dyneema body
• Fitted back panel and dual-strap reverse pull hip belt

Points of concern

• The detachable hip belt tends to shake and lack stability the more weight you carry
• The back is not very breathable
• No internal storage (such as a hydration sleeve)

Main specifications and evaluation

Detailed Review

Appearance and usability: The revised stitching design has significantly improved storage capacity and usability

Up until now, HMG backpacks have had a strong image of being made up of a single piece of fabric all the way around the back with minimal stitching, creating a slightly semi-cylindrical "tubular" structure, but the new Unbound has completely changed that. Four pieces of fabric are sewn together on the front, back, left and right, creating a more square-like form that gives a sharper, more refined impression

If you look closely, you'll see that the seams on the main body face outward, which is a major difference from the company's previous models, and the device is attached in a daisy chain along those seams

I'm sure I'm not the only one who thought this design change looked great at first glance, but of course it wasn't just because of the new design

The advantages of the cylindrical design are that it is lighter and more durable and water-resistant due to fewer seams and less fabric. However, for a long time, HMG backpacks (although there are now a few more variations) have tended to have minimal external pockets and attachments, and the construction, with its loose mesh and loose gussets, can be described as plain and simple, or, at worst, rough (the photo below is of a WINDRIDER 2400 that I used to carry)

the Unbound comes in . It's made by joining together four pieces of fabric on the front, back, left and right, and the seams that would normally be woven on the inside are deliberately reversed (on the outside). By sewing pockets, daisy chains and other storage parts along those seams, they've succeeded in increasing the external storage space, which was previously limited (see photo below).

On the other hand, the inside of the pack has flat seams, making it easy to apply waterproof seam tape. As a result, the pack remains just as water-resistant as a conventional cylindrical design (see photo below)

Even with the increased amount of fabric and seams, the weight has not increased significantly (compared to the previous model, the Windrider 2400 ). While the weight savings are somewhat offset by less obvious factors such as the smaller buckles, the increased storage space and other improvements in convenience mean that the weight is hardly affected.

External pockets made from durable and stretchy Dyneema stretch mesh

There's no doubt that the newly designed external storage system has largely eliminated complaints about conventional lightweight backpacks, such as "there aren't many small compartments and it's hard to use" or "it's a pain to have to open and close the main compartment every time you want to take something in or out." In that sense, the new storage options (including the improvements from the previous models) are all things we would like to welcome wholeheartedly

My favorite feature is the front and bottom pockets, which are made with Dyneema stretch mesh. They are really well made

First, let's talk about the material. Dyneema Stretch Mesh is a cutting-edge fabric made from a high-strength nylon and polyurethane woven fabric reinforced with Dyneema fibers in a grid pattern, achieving extremely high abrasion and tear resistance and four-way stretch. It's incredibly durable and stretchy. It has a strong kickback, so it sticks tightly to the pack when empty, but stretches easily when you need to take items in or out

The Unbound has three pockets made from this cutting-edge stretch material: two on the front and one on the bottom

The two front entrances are connected at the bottom, and the upper pocket is deep and large (see photo below). I usually put rain gear, jackets, and other items like the footprint (ground sheet) that I tend to pack last in the upper pocket, and snacks and gels in the lower pocket

The remaining one is attached in an unfamiliar location on the bottom of the pack

The entrance is on the right side, and there is no zipper or other opening. At first glance, you may be worried about whether it can actually be used, but when you actually use it, although it has a quirk, it has the advantage of being able to access it quickly by reaching out while walking, and it has the potential to be used in a variety of ways

First of all, the basic intended use is to store snacks (see photo below). There is also a small opening on the opposite side of the entrance (left corner) where you can tuck in bags or other items after eating, which is a very stylish little detail

Of course, it has been possible to use a sacoche or something similar as a substitute in the past, but when you are moving quickly it is best not to have anything hanging around your body, so this does have its own benefits

If this pocket were made with a regular fabric of the same thickness, it would wear out and tear in no time. The key point is that this new fabric, which combines durability and high kickback, makes it possible. However, personally, I would like it to have at least a Velcro closure at the opening to prevent the contents from falling out

In addition to food, it can be used for a variety of purposes depending on your ideas, such as storing jackets, rain gear, mats, dirty clothes, etc. In my case, it seems like a good idea to store a 10-20m "help rope" that I often use when climbing streams

Large capacity, easy-access side hipbelt pockets

The pockets on the sides are large enough to fit two or more bottles. You can reach behind you and take them out without having to remove the bag, and the drawcord-type opening prevents the bag from sagging

When combined with the standard side compression straps, you can attach not only bottles but also tripods, trekking poles, and even closed-cell mats (adjustable length)

By the way, it is most effective to use the Y-shaped compression strap at the top to secure the mattress. In the UK, the strap is very long, likely because it is intended to be used to secure bear containers and other items. You can also secure long ropes for climbing

The hip belt pockets are large enough to fit even a large 6.7-inch smartphone, with one on each side (see photo below). They're getting bigger every year to accommodate the ever-increasing size of smartphones. They're also reasonably waterproof, so you can safely store your electronic devices

Great expandability! Daisy chains scattered throughout

The new design allows for an abundance of daisy chains, allowing you to attach external attachments such as carabiners and drawcords to customize your storage

For example, you can attach your own cord lock to the side and use it as a pole attachment (top left photo below), attach a smartphone pouch or bottle holder to the shoulder strap (top right photo below), attach a carabiner to the bottom (bottom left photo below), or attach the original camera pouch to the hip belt (bottom right photo below).Although you will need to add your own parts and make adjustments, the possibilities for use are endless, depending on your ideas

By the way, the daisy chains on the sides are not just loops, but also function as compression straps thanks to the drawcords that come as standard. This makes it very convenient to make the backpack thinner and prevent it from shaking when you have less luggage (see photo below)

Material and durability: Ultra-lightweight, highly durable Dyneema fabric made with a unique blend that can only be found in this brand

When you think of HMG, the first thing that comes to mind is undoubtedly the Dyneema material that has been consistently used since the company's founding. The Dyneema material that is the source of that philosophy is of course still alive and well in this backpack

The Dyneema fabric "DCH (Dyneema Composite Hybrid)" used in all HMG backpacks is a fabric that has been significantly enhanced in durability by laminating a lightweight polyester fabric to the Dyneema composite fabric (DCF) commonly used in tents. It is said to achieve the same tensile strength as 500 denier Cordura nylon at half the weight. Only HMG, thanks to its long-standing partnership with DSM, the world's largest supplier, is able to use this lighter, more durable proprietary blend of Dyneema fabric*

Regardless of the technical details, if you try lifting this model and then putting some luggage inside and carrying it outside, you'll realize how light and strong it is, like a paper bag that won't tear no matter how much you drag it around

*Reference: SectionHiker.com

Comfort: Lightweight yet still comfortable

The Unbound 's back system is designed to carry lighter loads than a typical hiking backpack, so the back frame does not cover the entire back, but rather has a single removable aluminum stay that runs through the part that touches the spine.

The number of vertical aluminum stays has been reduced from two to one, as with previous HMG backpacks, so you might think that this would affect comfort, but strangely enough, it doesn't feel like a big deal. The perfect curve that follows the spine and the reinforced foam padding on the back make it as comfortable as ever

However, one thing to note is that you still can't expect much breathability from the back. The back is in close contact with the pad, and although the fabric itself dries quickly, sweat tends to stick to it, so it's not particularly comfortable

Comfort of carrying ② (stability): The heavier the load, the more unstable the bag becomes

There was no problem with the comfort of carrying a bag up to about 5 kg, but when I tried to stuff it fuller, things started to change a little

First of all, the Unbound 40 is designed with high-speed through-hiking in mind, and so the hip belt is also removable (see photo above). This is because if you lighten your load to the extreme, even the hip belt can get in the way, so you can omit it. This is certainly understandable.

However, it is also true that this reduces (and weakens) the number of connections between the hip belt and the pack, which is clearly a negative factor in load stability

In fact, compared to previous models where the hip belt was sewn to the waist (at least the WINDRIDER that I was carrying), when carrying a heavy load of about 10 kg, I feel like my body starts to shake more strongly when walking (see photo below)

Of course, it won't be such a big deal if you don't carry a weight that makes it noticeable, but the way I envision using it I'm assuming it will be quite heavy, so I'd like to do something about it if possible

The simplest solution would be to just sew it on, but after some experimenting, I found a way to significantly reduce wobble with just two straps. This is by using the daisy chains that run throughout the pack. Since both the pack body and the hip belt have daisy chains, there's no reason not to use them

Just thread any strap of suitable length through the daisy chains on the bottom of the backpack and the hip belt and fasten it. This way, even with a heavy load, the backpack and body are pulled closer together and secured in place (see photo below). If you're interested, give it a try

Summary: The stable lightness and durability, plus the outstanding storage capacity, make this a backpack that is even more "fun to use."

Hyperlite Mountain Gear THE UNBOUND Backpack

created by Rinker

• Hyperlite Mountain Gear UNBOUND (official website)

that Hyperlite Mountain Gear 's new hiking backpack, the Unbound 40 , is one of the best backpacks available today for hikers who want to go lighter, faster, and further. Those who already know the quality of HMG will appreciate the clear upgrade, which adds significant storage capacity and expandability while maintaining the appeal of its lightness and durability. Even those trying an HMG backpack for the first time will be able to rediscover the brand's original appeal of functional beauty with its many sophisticated, comfortable, and convenient features.

However, I think you can generally use it with almost no complaints, but as mentioned in the reviews, you need to be a little careful if you pack it close to its limit. If you can deal with these issues properly, there are currently almost no noticeable complaints about this pack, and with some customization it has the potential to become an unbeatable backpack that can handle any mountain activity at a top level (except for serious trail running), so my expectations are only growing

   

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