Hyperlite Southwest 55 vs Zpacks Arc Haul Ultra 50L
How we did this: we compared what Hyperlite Mountain Gear and Zpacks publish on their own product pages, checked on 29 Sep 2026: weight, volume, load rating, frame, fabric and price. We have not field-tested these packs.
The Hyperlite Southwest 55 and the Zpacks Arc Haul Ultra 50L are the two framed, waterproof-fabric packs thru-hikers compare most. The Arc Haul Ultra is 9.4 oz lighter and $21 cheaper. The Southwest has a much larger main body than its “55 vs 50” label suggests, removable stays and tougher solid-fabric pockets.
Hyperlite Southwest vs Arc Haul Ultra: the verdict up front
Pick the Zpacks Arc Haul Ultra 50L if weight comes first: 21.4 oz, a carbon frame that holds the pack off your back, and $399. Pick the Hyperlite Southwest 55 if you need room and toughness: far more main-body volume, solid-fabric pockets for brush and rock, and $420.
| Spec | Hyperlite Southwest 55 | Zpacks Arc Haul Ultra 50L |
|---|---|---|
| Weight | 30.8 oz (874 g), medium, white | 21.4 oz (608 g), lightest configuration |
| Price | $420 | $399 |
| Volume as listed | 55 L pack + 13.4 L external | 50 L total: 37 L main, 2 × 2.5 L side, 8 L front |
| Load rating | Up to 40 lb | 30–35 lb comfortable, 40 lb max |
| Frame | Two removable contoured aluminum stays, 1/4″ foam back panel | Curved carbon fiber Arc Frame with an air gap |
| Fabric | Dyneema Woven Composite 3.9 (woven 200-denier Dyneema face) | Ultra 100X, 3.3 oz/sq yd (woven UHMWPE face, waterproof backing) |
| Outside pockets | Solid fabric | Side pockets take two 1 L bottles each |
| Torso | Sizes XS to Tall | Adjustable torso height, 3 frame heights |
| Hip belt | Dual-density foam, zippered Dyneema pockets | Interchangeable padded belt |
Sources: Hyperlite Mountain Gear Southwest page; Zpacks Arc Haul Ultra 50L page.
Hyperlite vs Zpacks: why 55 L vs 50 L undersells the gap
The two makers count volume differently. Zpacks’ 50 L is everything: a 37 L main body, two 2.5 L side pockets and an 8 L front pocket. Hyperlite lists the Southwest 55’s pack volume as 55 L and its external pockets separately, at 13.4 L. On the makers’ own numbers, the Southwest’s main compartment is far larger. For a bear canister or a winter quilt, that matters more than the 5 L in the names.
Hyperlite Southwest 55
- Much larger main body
- Solid-fabric pockets resist snags
- Stays come out for light loads
- 9.4 oz heavier than the Arc Haul Ultra
- $21 more
- Foam back panel rests against your back, no air gap
Hyperlite recently moved the Southwest to a new fabric. In Hyperlite’s words, the main body is
“built with a new, fully woven Dyneema® 200-denier fabric that offers more durability than ever before.”
Hyperlite Mountain Gear, Southwest page
It keeps the roll-top with vertical compression straps and a top Y-strap, a 1/4″ foam back panel, two removable contoured aluminum stays, and a dual-density hip belt with zippered pockets. Vertical side seams are taped. Hyperlite rates it to 40 lb.
Check price →Zpacks Arc Haul Ultra 50L
- 9.4 oz lighter than the Southwest
- Carbon Arc Frame holds the pack off your back
- Adjustable torso, interchangeable belts and straps
- 37 L main body is much smaller
- Pocket space is counted inside the 50 L
- Comfort tops out at 30–35 lb
Zpacks builds the Arc Haul Ultra 50L from 3.3 oz/sq yd Ultra 100X, a woven UHMWPE face laminated to a waterproof backing. Its curved carbon fiber Arc Frame leaves an air gap behind your back and transfers most of the weight to a hip belt that connects directly to the frame. Zpacks says the 50 L is
“enough space for 4-5 day carries on a thru-hike with ultralight gear.”
Zpacks, Arc Haul Ultra 50L page
The side pockets each take two 1 L bottles and sit low and angled forward. Zpacks rates the pack at 30–35 lb comfortably and 40 lb at most.
Check price →Which should you buy?
- Lightest framed pack: Zpacks Arc Haul Ultra 50L, 21.4 oz.
- Bear canister, winter quilt or long food carries: Hyperlite Southwest 55, for the larger main body.
- Off-trail, brush and rock: Hyperlite Southwest 55, for the solid-fabric pockets.
- Hot weather: Zpacks Arc Haul Ultra 50L, for the air gap behind your back.
FAQ
Hyperlite vs Zpacks: which pack is lighter?
Is the Arc Haul Ultra 50L really smaller than the Southwest 55?
How much weight can each pack carry?
Are these packs waterproof?
Can you remove the frame to save weight?
The bottom line
The Arc Haul Ultra 50L wins on weight by 9.4 oz and on price by $21. The Southwest 55 wins on usable space and toughness, and its labels undersell how much larger its main body is.
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