HMG Unbound 55 Review: Frame, Fit and Load Comfort
What it is
This HMG Unbound 55 review covers Hyperlite Mountain Gear’s 55-liter roll-top pack, which HMG designed for thru-hikers and long-distance backpackers who need more room than a 40-liter pack: seasonal layers, a bear canister, or extra food and water between distant resupplies. The current version is built from Dyneema® Woven Composite 3.9 and weighs 28.9 oz in size medium, according to HMG. The original DCH version, still sold by some retailers, is listed at 30.1 oz.
Who it's for
It suits hikers with a light base weight who occasionally carry bulkier loads. HMG rates it for loads up to 40 lb. If you never need more than 40 liters, the Unbound 40 (27.3 oz) does the same job lighter.
Design and details
Per HMG’s spec sheet: the main body is Dyneema® Woven Composite 3.9, with 100D Dyneema Gridstop and Dyneema stretch mesh for the pockets. Two contoured aluminum stays and a foam back panel form the frame; both stays can be removed to save weight. The hipbelt is removable and cinches with a V-Pull system. Storage is a dual-entry stretch-mesh front pocket, two side bottle pockets and a bottom pocket, adding 9 liters of external volume to the 55-liter main body. The roll-top is removable and has vertical compression straps, with a Y-strap over the top, removable side compression and shock-cord lashing, and low-profile daisy chains. Seams are taped inside. It comes in four torso sizes: small (15–17 in), medium (17–19 in), large (19–21 in) and tall (21 in and up).
Hyperlite Mountain Gear Unbound 55
- Durable and highly water-resistant DCH construction
- Front, side and bottom pockets reachable on the move
- Removable hipbelt, stays and roll-top
- Four torso sizes, rated to 40 lb
- Foam back panel runs warm in hot weather
- Compression system needs setup before first use
- Premium price point for a minimalist design
At 28.9 oz for 55 liters plus 9 liters of pockets, the Unbound 55 carries more volume per gram than most framed packs its size. Removable stays, hipbelt and roll-top let you strip it lighter on easy stretches of trail.
Check price →Performance
HMG gives a load capacity of up to 40 lb. The two contoured stays and the foam back panel carry the weight; HMG says the updated stays add support for heavier loads, and the redesigned shoulder straps are wider with a more natural curve around the neck. We haven’t carried it ourselves, so we can’t tell you how it feels at 35–40 lb. If you often carry near that limit, load it with your own kit before you commit.
Dyneema® Woven Composite does not absorb water, so the pack doesn’t gain weight in rain the way a nylon pack does, and the taped internal seams limit leaks at the stitching. A roll-top is only as dry as the closure, and the mesh pockets stay exposed, so keep your sleeping bag and electronics in a dry bag or liner.
HMG describes the new Woven Composite 3.9 as exceptionally durable. As with any Dyneema-based fabric, expect scuffing if it is regularly dragged over rock, and treat the stretch-mesh pockets gently in thorny brush.
The pocket layout is built for use on the move: bottles in the side pockets, a jacket or wet shelter in the dual-entry front mesh, and snacks or trash in the bottom pocket, all reachable without taking the pack off.
The tradeoffs
The main trade-off is breathability. The foam back panel sits directly against your back, so expect a sweaty back on hot climbs. That’s typical of packs in this class rather than a flaw specific to this one.
The second is cost. At $420 from HMG, it’s in the premium tier. You pay for the Dyneema fabric and the low weight.
Much of the compression and lashing is removable and customizable. That’s good for tuning the pack to your kit, but it takes a little setup before your first trip.
Is it worth it?
HMG sells the updated Unbound 55 for $420. Our catalog lists $415, and when we checked, Feathered Friends had the original version at $332. For a thru-hiker who will carry it for thousands of miles, the volume-to-weight ratio justifies the price. For occasional weekend trips, a cheaper nylon pack a few ounces heavier is better value.
Who should skip it
Skip it if you regularly carry more than HMG’s 40 lb rating (winter kit, climbing gear, big water carries), if you hike mostly in hot, humid conditions and want a ventilated back panel, or if you never need more than 40 liters. In that last case, the Unbound 40 is lighter.
FAQ
Does the Unbound 55 fit a bear canister?
Is the HMG Unbound 55 waterproof?
Is the hipbelt removable?
What changed in the updated Unbound 55?
Can I attach trekking poles or extra gear?
Should I choose the Unbound 40 or the Unbound 55?
How do I clean a Dyneema pack?
The bottom line
The Unbound 55 is a 55-liter Dyneema pack with a two-stay frame, rated to 40 lb, at 28.9 oz in its current version. It’s aimed at thru-hikers who need occasional extra volume without a heavy pack. If that’s you and the $420 price is acceptable, it belongs on your shortlist. If you don’t need 55 liters, the Unbound 40 is lighter.
Related guides
Keep building your system with these closely related guides.
- What Denier Actually Tells You About A Fabric
- Zpacks Arc Zip Ultra 62L Review: Carry, Capacity And Weight
- Overnight Packs
Further reading
Authoritative sources to go deeper on the topics above.
