Zpacks Arc Haul Ultra 50 Review

The Zpacks Arc Haul Ultra 50 is the updated version of the pack that made Zpacks so popular among thru-hikers. Now made with robust and water-resistant Ultra 100X material, this new take on an old classic is an ultralight hiker’s dream.

The curved carbon fiber frame helps to keep the weight of the pack off of your back, allowing for airflow to help prevent you from overheating. This pack is perfect for minimalist hikers who still want the added comfort of a framed backpack. 

Zpacks Arc Haul Ultra 50 Specs

MSRP: $399 
Capacity: 50L (37L main body, 8L external rear mesh pocket, 2.5L each side pocket)
Weight: 21.2 oz
Max Load: 40 lbs 
Materials: Ultra 100X

Intended Use

This pack would best serve hikers with a very low base weight (<10 lbs) who value the added comfort that framed packs provide. 

Conditions of Review

At the time of this review I have put approximately 1,250 miles and 45 days of use on this pack between a section hike of the Colorado Trail and a long section hike of the northern portion of the Continental Divide Trail.

I have used this pack in a variety of weather conditions, including rain, sleet, and snow. I’ve taken it off the beaten path for some pretty rigorous bushwhacking and carried it on many long-mile days. My carried weight has varied between about 10-30 pounds depending on the amount of food and water I had at any given time.

Other packs I have carried, which will serve as my basis for comparison for this pack, include the REI Flash 55 (2,200 miles on the AT), the Hyperlite Mountain Gear Southwest 2400 (500 miles on the CT), and the ULA Circuit (2,600 miles on the PCT). 

Zpacks Arc Haul Ultra 50 Features

Ultra: Ultra fabric is a woven Ultra High Molecular Weight Polyethylene (UHMWPE) face fabric laminated to a waterproof backing. Ultra does not contain a DWR coating and is PFAS-free. It is incredibly durable with high abrasion- and tear resistance. 

Curved Carbon Fiber Air Stays: These help to keep the back off your back, allowing for airflow and reducing uncomfortable rubbing

Roll-Top Closure: Along with the taped seams, the top closure gives this pack a high level of water resistance 

Adjustable Shoulder and Sternum Straps: Both the shoulder straps and the belt are ⅜”  thick and contain a daisy chain system to allow adjustment to the sternum strap position or clipping on other items

Removable Top and Base Straps: Allows you to strap extra gear to the outside of the pack

Removable Hip Belt: The hip belt is fully removable and interchangeable, allowing you to swap between different-sized belts 

Integrated Load Lifters: Load lifter straps are attached to the shoulder straps, allowing for a more comfortable carry

Roomy Side Pockets: Side pockets are large enough to fit two 1L water bottles each, and are angled down to allow easier access

Comfort

I was extremely skeptical of the frame’s ability to keep the pack’s weight off my back, but I was happily proven wrong. Even when fully loaded, I was able to slide two fingers between my back and the pack, which led to a significantly more comfortable carry than other ultralight packs that I have experience with.

Although the airflow was not sufficient to really keep my back cool, it was significant enough to make a noticeable difference in comfort. Similarly, I found the shoulder straps comfortable and the load lifters very effective at helping balance the pack’s weight efficiently.

That said, the hipbelt on this pack is not very effective at distributing weight. In fact, it was disappointingly ineffective. I removed the hipbelt of the pack for approximately a 150-mile stretch and noticed basically no difference in the weight distribution of the pack. It seems that its only benefit is to reduce sway in the pack as you move. I do like the dual adjustment on the hipbelt, which allows you to tighten the top and bottom of the belt separately.

It is important to remember that this pack is designed to carry low weights. Although the pack is rated for a max load of 40 pounds, it becomes uncomfortable at around 20-25 pounds. Above this weight, the pack really begins digging into your shoulders and lower back where the hipbelt attaches. This was rarely a real issue, but it did make long food and water carries more of a pain than they otherwise should have been.

An often overlooked aspect of a comfortable pack is the ease with which you can access your water in the side pockets. As with all packs, this did require some level of flexibility, but I was happy with my ability to store and retrieve water on the go. It was undoubtedly easier to do this with this pack than any other ultralight pack I have used in the past.   

Durability

I should preface this by saying I am pretty rough on my gear. I’m a firm subscriber to the belief that gear is a tool (not a jewel) and that a natural part of use is abuse. 

The fabric of the pack held up incredibly. After tossing the pack on the ground countless times and putting it through miles of bushwhacking, there is no evidence of abrasions or tears on the pack’s body. There are some small tears on the netting of the rear pocket, but not to a degree that inhibits the ability of the pack to perform. It is nothing more than a small cosmetic issue. 

I did have part of the frame of the pack snap after about 900 miles of use. The point of failure was a horizontal stay that connects the two vertical carbon fiber stays. It broke while I was wearing it, seemingly out of the blue. The pack was not overloaded and I had not previously seen any signs of wear on this part.

This was not a major issue as the pack still functioned fine, just without the benefit of the “off the back” feature added by the frame. Zpacks quickly sent me a replacement part under the warranty, and it was a very easy fix. Still, pretty disappointing as I believe the main value of this pack comes from its frame system. 

Zpacks Arc Haul Ultra 50 Pros

The Material: Ultra is a pretty incredible material. I was amazed by its durability and water resistance. Although I kept my sleeping bag in a liner as an added layer of protection, it was never needed. Even after hard, sustained periods of rain, the inside of my pack was completely dry. Plus, no PFAS forever chemicals. 

The Weight: 21.2 oz is pretty impressive for a framed pack. Is it the lightest pack out there? No, but it is amazingly light for what it is. 

The Comfort: At low weights this pack is incredibly comfortable. 

The Interchangeable Hip Belt: I dropped a hip belt size on trail and was happy I was able to change it out without needing a full new pack.

Zpacks Arc Haul Ultra 50 Cons

The Lack of Basic Features: I understand that Zpacks is making an effort to keep the pack as light as possible, but some things should come standard. Things like hip belt pockets and ice axe loops should not be sold separately. 

The Cost: $399 is too expensive for what this pack is. If I were to add on the “extras” that I think should come standard (two hip belt pouches and an ice axe loop) that brings the price up to $474.85. If you wanted a fully tricked-out pack with all the add-ons (hip belt pockets, ice axe loop, chest pouch for your phone, water bottle sleeve, additional padding for your shoulder straps and hip belt, additional side pocket, Side closure straps, and a V-Top strap) you’re looking at $663.45.

Overall Value

I really like this pack and I will continue to use it, but I would only recommend it under two very specific circumstances.

 First, you need a low enough base weight (<10 lbs) for this pack to be effective. 

Second, you have to really value the comfort added by a frame. 

I suspect that the center of the Venn diagram containing these two prerequisites is small. If your base weight is that low, comfort is likely a lower priority for you than weight. If that is the case, buying a frameless pack makes much more sense. High-end frameless packs are lighter than this one and often cheaper.

That said, if both of those conditions apply to you (ultralight, values comfort), the Zpacks Arc Haul Ultra 50 is an excellent option. The comfort added by the frame is significant and could well be worth a few extra ounces and dollars.

Shop the Zpacks Arc Haul Ultra 50

Comparable Packs

The following are some of the very basic specs for packs I think are similar to the Zpacks Arc Haul Ultra 50L. This is not intended as a review of any of these packs, but rather serves as a recommendation of other pieces of gear to consider. 

Hyperlite Mountain Gear Unbound 40

• Price: $369
• Weight: 29.6 oz
• Capacity: 49L (40L internal)

Pa’lante Desert Pack

• Price: $270
• Weight: 18.6 oz
• Capacity: 43L (37L internal)

LiteAF UltraWeave 40L Curve

• Price: $305
• Weight: 17 oz
• Capacity: 55L (40L internal)

The Zpacks Arc Haul Ultra 50 was donated for purpose of review