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How to Choose an Ultralight Backpack

The very tall top of the Windrider 3400's main pack allows you to scale up and down in pack volume. When you go big  you will want your lightest bulky items up top.
Sunday January 31, 2016

Each year, it seems that modern equipment gets lighter and lighter, so its no surprise that backpack technology is on the same track. Its hard to go back to a 4 or 5 pound pack once you've experienced the freedom of carrying only 25 pounds total! In this review, we have selected only packs that weight under 2 pounds, the lightest weighing in at only 1 pound 2 ounces total. Because they are lighter, they are also lower volume, most of them average around 38 liters. For comparison, most of the packs we test in our Best Backpacking Backpack weigh in between 4 and 6 lbs, and have a main compartment volume of 60 liters or so. If you most often head out with more than 30 lbs of equipment and food, these bigger, burlier packs are your best choice.

None of the ultralight packs we tested will be comfortable with a 40 lb load and it's unlikely that you'll be able to fit that much gear anyway. Head over to our Backpacking Backpack review for larger load carriers.

This is an updated review and is the third in our series of reviews and articles for lightweight and ultralight backpackers and thru-hikers. Check out our Best Ultralight Sleeping Bag and Best Ultralight Tent Shelter reviews for the best of the best products to build your ultralight kit. The Buying Advice sections of these two reviews defines what we consider to be ultralight and lightweight loads for backpacking, and they provide very detailed advice on choosing a tent shelter, sleeping bag, and sleeping pad that will allow you to pare your kit down to very low weights — while still maintaining a comfortable safety margin in the backcountry.

The two previous generations of the ZPacks Arc Blast...our lead tester is wearing our test model. Drawing on the experience of our extended group of testers and friends creates the world's best side-by-side gear reviews.
The two previous generations of the ZPacks Arc Blast...our lead tester is wearing our test model. Drawing on the experience of our extended group of testers and friends creates the world's best side-by-side gear reviews.

This brings us to our next point. The ultralight backpack is a part of a complete featherweight kit. These lightweight packs are great, but if your gear doesn't match, chances are a pack of this size will not be very useful to you. We found it to be important to do a test run with your gear and load up your kit in the pack you intend to purchase. The top scoring packs we tested here are, in our opinion, the best out there for carrying 15 to 30-pound total loads, whether it's on a weekend trip to your favorite backcountry locale, or a five-month adventure from Mexico to Canada.

Types of Ultralight Backpacks


We will start of by discussing the different types of ultralight packs: Simple Frame, Tensioned Air Frame, and Frameless.

Simple Frame


Simple frames come in a couple of varieties, and for this grouping we define a simple frame as a frame that is not arc-ed and held in tension to create airspace at your back. At the simplest end of the frame spectrum is the throwback design of the Hyperlite Mountain Gear Windrider, with two independent flat aluminum stays placed vertically in the back panel. More advanced are the upside down U shaped frames of the Editors' Choice Gossamer Gear Mariposa and the ULA Circuit, in tubular aluminum and carbon/Delrin respectively.

Simple frames prevent torso collapse in the pack body, and help load transfer to the hip belt. The models we tested with simple frames are:
  • Gossamer Gear Mariposa
  • Gossamer Gear Gorilla
  • ULA Circuit
  • ULA Ohm 2.0
  • HLMG Windrider 3400
  • Haglofs L.I.M. Strive 50
  • Ultimate Direction Fastpack 30

Out for a trip along the Continental Divide in Rocky Mountain National Park with the HMG Windrider. We found the simple aluminum stays in this model inferior to more modern simple frames like that of the Gossamer Gear Gorilla  which more comfortably carries 25 or 30 pounds.
Out for a trip along the Continental Divide in Rocky Mountain National Park with the HMG Windrider. We found the simple aluminum stays in this model inferior to more modern simple frames like that of the Gossamer Gear Gorilla, which more comfortably carries 25 or 30 pounds.

Tensioned Air Frame


Several of the packs we tested incorporate a tensioned frame that is not only designed to carry loads well, but creates space at your back for air flow. Many hikers that tend to sweat a lot or whose adventures are primarily in warm to hot seasons of the year prefer a pack with ventilation between a potentially sweaty back and the backpack. The Best Buy Osprey Exos 48 and Top Pick ZPacks Arc Blast 55 both use light tensioned frames.

In addition to usually carrying heavier loads more comfortably, a tensioned frame creates ventilated airspace between your back and your pack's body. The models we tested with tensioned frames are:
  • Osprey Exos 48
  • Osprey Levity 45
  • ZPacks Arc Blast 55
  • Mammut Creon Light 45

Surveying the Divide from the Mummy Range in RMNP. We found the tensioned air frame of the Osprey Exos 48 the best of this bunch for carrying 25 pounds or more. The Exos isn't the lightest pack we tested  but it includes all the bells and whistles.
Surveying the Divide from the Mummy Range in RMNP. We found the tensioned air frame of the Osprey Exos 48 the best of this bunch for carrying 25 pounds or more. The Exos isn't the lightest pack we tested, but it includes all the bells and whistles.

Frameless


For very light loads, many enthusiasts carry a smaller pack than those we tested here. With overall loads less than 15 pounds, a frame becomes less important for carrying comfort. But in this review, we focused on packs capable of carrying loads up to 30 pounds when necessary. The only frameless pack we tested, the Granite Gear Virga 2, is a throwback to an era when many if not most backpackers carried a closed cell foam sleeping pad. The Virga is designed to function best when a rolled closed cell foam pad is placed inside forming a barrel-like frame.

The Granite Gear Virga 2 is a large volume frameless pack that performs best when a rolled closed cell foam pad is placed inside forming a "barrel frame."

Best Uses for Ultralight Backpacks


Seems fairly simple, right? You'll find these ultralight packs perfect for you if your backpacking adventures are focused more on covering the miles in unburdened comfort, and focused less on carrying lots of kit and luxuries for camping. In addition to the main compartment, lots of external storage provides quick access to food and important clothing layers while on the go.

Headed up into Colorado's Indian Peaks Wilderness for a peaceful overnight and some sunrise fly fishing in the high alpine lakes. With a very light load  the frameless Granite Gear Virga 2 was a good choice.
Headed up into Colorado's Indian Peaks Wilderness for a peaceful overnight and some sunrise fly fishing in the high alpine lakes. With a very light load, the frameless Granite Gear Virga 2 was a good choice.

Ultralight Backpacking


To us here at OutdoorGearLab, ultralight backpacking is primarily defined by minimalism; carrying just the right amount of the best gear to stay safe, warm, and happy while covering our trail miles. Most experienced thru-hikers and ultralight enthusiasts that we know have developed three-season backpacking kits with a base weight of 7 to 11 pounds. At the lighter end of this spectrum, many forgo a stove for cooking. At the heavier end are folks that cook some of their meals, carry a few extra warm clothing layers, and have a few luxury items like a camera or a book or two. Add in consumables and pack weights are often in the high teens or low 20s. When our lead tester packed for a wintertime 250-mile chunk of the Appalachian Trail, his base weight came in at 13 pounds.

We strongly feel the four top-scoring packs we tested (all of which have minimal frames for support) are the best choice for most ultralight backpackers for three-season use. The best of these packs also provide the capacity and load carrying ability tackle cold, winter conditions. For folks with heavier base weights or scaling up for winter, we recommend the fully-featured Gossamer Gear Mariposa. On the other end of the spectrum, the ZPacks Arc Blast 55 is our go-to pack when total weight rarely gets above the teens.

Lightweight Backpacking


As we define lightweight backpacking, base weight is between 13 and 20 pounds. Many novice backpackers seeking to reduce their loads to the lightest possible weight without compromising their safety or spending a few thousand dollars on equipment fall into this realm. It is quite common for relatively new folks gearing up for a thru-hike of a long trail to develop a kit that weighs in around 13 to 15 pounds. You can pull this off quite affordably. With a base weight in this range, you'll commonly carry 25 pounds once you add in consumables. An ultralight pack with a simple frame or tensioned frame for support is the perfect choice for you. The Gossamer Gear Gorilla, ULA Ohm 2.0, and Osprey Exos 48 handle these loads really well.

Out on a dayhike with a light load in the REI Flash. We went out for long day with both light and medium loads to evaluate each pack's carrying comfort and adaptability. Wandering around up at Chief Hosa  Colorado.
Out on a dayhike with a light load in the REI Flash. We went out for long day with both light and medium loads to evaluate each pack's carrying comfort and adaptability. Wandering around up at Chief Hosa, Colorado.

Thru-hiking


Thru-hiking, or tackling one of the many popular long-distance trails like the Pacific Crest Trail or Appalachian Trail, is really no different than ultralight and lightweight backpacking described above. With the exception that the time spent carrying your house and home on your back is measured in months rather than days or weeks. While paring down your kit to the lightest safe weight for you is compelling, so is the ability to carry a substantial load when it is necessary. In sections of the Mojave desert in Southern California, PCT hikers need to carry six or more liters of water on a few days. On long trails, it is also not uncommon to carry a week's food or more while hiking through some of the more remote terrain. The Gossamer Gear Gorilla, ULA Ohm 2.0, Osprey Exos 48, and the Osprey Levity 45 are all excellent choices for thru-hikers because they can comfortably handle the heavier loads that are sometimes necessary. The ZPacks Arc Blast 55 is perfect for folks moving fast enough to avoid the heavier loads.

Taking a stop to brew some coffee while whizzing through Great Smoky Mountains National Park in winter. The Gossamer Gear Gorilla carried Brandon's mid 20s pound load very comfortably. The Gorilla earned our second highest overall score.
Taking a stop to brew some coffee while whizzing through Great Smoky Mountains National Park in winter. The Gossamer Gear Gorilla carried Brandon's mid 20s pound load very comfortably. The Gorilla earned our second highest overall score.

Backpack as Part of a System: The Big Four


We talk a lot about the Big Four when it comes to selecting your backpacking kit. This includes your shelter, sleeping bag, sleeping pad, and pack. For most backpackers focused on hiking with very light loads, these are the four heaviest single items carried. You'll see that many other authors describe the Big Three. Here at OutdoorGearLab, we feel a good sleeping pad is as critical as the other three items for safety and comfort. Again, see our buying advice for tent shelters for the fine details of how the weight of these items adds up. To define some general weight ranges for lightweight and ultralight backpacking kits, the most important measurement is base weight. Base weight is defined as the total weight of the equipment commonly carried on your back, not included the weight of consumables like food, cooking fuel, and water.

Lightweight System


We define a lightweight backpacking kit as a base weight of 20 lbs or less. It is very common for thru-hikers, both new and experienced, to hit the big trails with a 13 to 15 lb base weight. A great goal for selecting the Big Four items is no more than 8 lbs total. This is usually a much more budget friendly goal as well.


Our recommendations for a 13 - 15 lb base weight, which means you'll often be carrying 25 lbs, and sometimes more, are the Gossamer Gear Gorilla, ULA Ohm 2.0, and Osprey Exos 48. We judged all of these packs' ability to comfortably carry 30 lb loads as "Great."

Ultralight System


We consider carrying a base weight of 12 lbs or less to be ultralight backpacking territory. Our lead tester carries a 13 lb base weight in winter that includes a few "heavy" luxury items. Most of our ultralight testers' three-season base weights are around 7 to 9 lbs. For the Big Four, 5 lbs total is an upper limit.


Our recommendations for folks building a 7 to 9 lb three-season base weight (which means you'll often carry 15 lbs and rarely more than the low 20s) are the ZPacks Arc Blast 55 and the Gossamer Gear Mariposa or the Gossamer Gear Gorilla. The Arc Blast is the best ultralight backpack if you very rarely carry loads above the teens. The added 8 ounces of the Gorilla are well worth it if you need to scale up your load carried. It handles loads in the mid 20s as well as any other we tested, and we feel it's much more adaptable for winter trips or carrying a week's worth of food and fuel.

The Big Questions


What Volume?


Two trends in the outdoor adventure world are contributing to both thru-hikers and backpackers carrying smaller backpacks than before. Compared to years past, we often carry less equipment and what we do select is more technologically advanced, multipurpose, and much lighter. A few years ago, it was not uncommon to carry a 65 liter pack with a 40 or 50 pound load for a week out in the backcountry. But today, packs with a main compartment volume of about 40 liters and the ability to carry another 10 liters or so in easy-to-access outer pockets are the most popular with experienced ultralight backpackers.

That said, most folks prefer a pack that errs on the side of larger rather than smaller. Its nice to have more room for big food loads when necessary and the ability to scale up your base weight for winter. Our lead tester usually rolls with a 7 lb base weight but scales up to 13 lbs for winter. The Mariposa easily accepts this bigger load and carries it well. A pack like the Exos 48 with an additional 10 Liters or so of storage is perfect for lightweight backpackers. It also carries a bit heavier loads better than others. We dialed in our selection for this review to mostly focus on models with an approximate 50-liter total volume.

We lugged a lot of chairs and odd shaped gear around while crewing our Leadville 100 runner this year.
We lugged a lot of chairs and odd shaped gear around while crewing our Leadville 100 runner this year.

Need to Carry a Bear Canister?


The volume that you choose will also depend on whether you'll need to carry a bear canister. If you will be hiking in California, you need a pack that will accommodate a bear-proof food canister for your trips in the Sierra. We tried out each of these packs with a BearVault BV500, the most common size bear canister carried by thru-hikers on the John Muir or Pacific Crest Trails (where canisters are required by law for long sections). Smaller bear canisters are available, but it can be difficult to fit food for a week (as well as your cook kit and fragrant toiletries) into these smaller cans. Increasingly, bear canisters are also a great idea on the Georgia to Great Smoky Mountains section of the AT, and again in New York and New Jersey. Canisters are also required by law in at least one short section in Georgia if you stop to camp there.

The Hyperlite Mountain Gear Windrider 3400 is the only recommended pack we tested here that plays nice with the BV500. Similarly, the Gossamer Gear Mariposa fits a bear can pretty well, as it has a slightly wider bottom than the Gossamer Gear Gorilla. If using a full-sized bear can is common on your trips, we highly recommend considering the slightly larger packs made by Gossamer Gear and ULA. These packs are described in the Other Versions sections of those model's individual reviews.

Do you want a Lid?


Another consideration when you're thinking about the volume of your ultralight backpack is whether or not you want a lid. A lid or a "brain" is a traditional part of backpacking packs. This pocket on top serves several purposes, but it adds a lot of weight relative to storage space and many lightweight pack manufacturers forgo a lid in their designs. In general, most of our testers and friends who are focused on very light kits do not use a pack with a lid, or they strip the lid off and leave it at home.

On the other hand, an adjustable lid is a perfect way to strap bulky but light items to the outside of your pack. You can capture your closed-cell foam sleeping pad under the lid. That said, all of the top-scoring packs we tested have other means of lashing a large sleeping pad to the outside. Carrying a climbing rope is one of the few applications that a lid handles much better than side or bottom lashing straps. If you're seeking an ultralight pack that also will double as your climbing approach pack, the Osprey Exos 48 and Mammut Creon Light 45 are the best choices. They are also both better at carrying more than 30 lbs than any of the other packs in this review.

How Much Weight Do You Usually Carry?


Most of the packs we tested in this review are more or less comfortable for carrying certain weights. This means that when considering a pack, you should be sure to think about how much weight you think you'll typically be carrying in order to get a pack that will be plenty comfortable. For loads from 10 to 20 lbs, we think the Arc Blast is the best choice. For loads from 15 to 25 lbs, we think the Mariposa is the best choice. And for loads from 20 to 35 lbs, we think the Exos is the best choice. These packs are constructed with different types of frames, fabrics, and padding, all of which contribute to their comfort at carrying different weights.

Only you know how much total weight you need to carry on your trips. On the CDT and Colorado Trail this summer  we met happy and successful hikers with total loads from 8 to 40 pounds. Ideal load range varies among the best three packs  each of which has its own niche.
Only you know how much total weight you need to carry on your trips. On the CDT and Colorado Trail this summer, we met happy and successful hikers with total loads from 8 to 40 pounds. Ideal load range varies among the best three packs, each of which has its own niche.

That said, you may not know how much weight you will usually carry…or you may plan to carry light loads sometimes and medium loads other times. In this scenario, you have three options: 1) Choose a do-it-all pack like the Mariposa that carries both types of loads comfortably but weighs a little extra. 2) Buy two packs (perhaps the Arc Blast and the Exos) to use with light loads and medium loads. 3) Decide that you're willing to sacrifice on comfort when carrying either lighter or heavier loads. In the case of the third scenario, you must ask yourself whether you'd rather have a very light pack that under-performs when carrying medium loads or a heavier pack that handles medium loads well. If you infrequently carry a medium load, or just don't mind the discomfort when it's loaded more heavily, then choosing a very light pack is a great option for you.

That said, most of our testers with many thousands of miles under their feet like the compromise of choosing a pack with a frame that is about half a pound or so heavier that the lightest available. Our favorite packs that we tested were the ones that are very comfortable with both light loads and medium loads. Our testers were happy to carry a bit of extra weight for the added comfort when their packs were loaded down into the 20s.

The top-scoring Gossamer Gear Mariposa and ULA Circuit are both ultralight packs that may be a little bigger and heavier than you need for your weekend trips, but they have the volume and load carrying capacity to take you on longer trips, and even into winter.

Other Considerations


Availability


If you're an experienced backpacker, you may not find it necessary to try on a pack before you buy it. You've likely worn a few packs before and have a good idea of your torso length and what size option of a pack will fit you the best. Nonetheless, if you want to get your hands on a pack before purchasing, you have a few options. If you spend a fair bit of time out playing in the backcountry, you've likely seen folks wearing most of the packs we tested. Make a new friend and ask to check out that cool pack you're thinking about getting. Many of the packs we tested aren't available from major retailers, so this is a good way to check one out in person.

That said, in the past few months, we've begun to see smaller manufacturers' packs become available in specialty shops. Packs from ULA and Hyperlite Mountain Gear are increasingly carried by a few small shops like Neptune Mountaineering in Boulder, CO (HMG) and Sage to Summit in Bishop, CA (ULA). Visiting an event like Trail Days in Damascus, VA, or a CDT Rockies Ruck, hosted by the Continental Divide Trail Coalition and the American Long Distance Hiking Association-West, is also a great way to check out a large variety of ultralight backpacks from small manufacturers. While most large manufacturer packs are available in just a couple sizes, many cottage industry pack makers offers lots of mix and match options. For example, the torso length of your pack is selected independent of the waist belt size. Visit the manufacturer's website for detailed measuring and sizing information.

The Granite Gear Virga 2 and Osprey Exos 48 peaking out from under the beak of the ZPacks Hexamid Twin Shelter.
The Granite Gear Virga 2 and Osprey Exos 48 peaking out from under the beak of the ZPacks Hexamid Twin Shelter.

Waterproof Cuben Packs


While we usually recommend using both a pack liner and a rain cover, as well as waterproof stuff sacks, when your trips take you to predictably rainy areas, two of the packs we tested offer much greater water resistance than the others. Not only is hybrid Cuben fiber very light, it is also waterproof. Both the ZPacks Arc Blast and the Windrider from HMG are (for most practical purposes) waterproof. Both also have sealed seams that do a brilliant job of keeping rain from soaking through to the inside of your pack. For a few folks, this is a deciding factor when choosing a pack for very rainy climates. Depending on what items you store in the external pockets, you'll still want a rain cover. Additionally, your most important items inside - sleeping bag and puffy jacket for instance - should be in waterproof stuff sacks.

Air Flow Suspension


Let's face it, some of us are very sweaty folks and not only when it's hot outside. If this is true for you, we'd recommend choosing a pack with a tensioned frame system that creates air flow between your ultralight backpack and your back and shoulders. Two of our award winners, the Osprey Exos and the ZPacks Arc Blast have tensioned frames that promote air flow. The Mammut Creon also has this feature. That said, we also found the removable "egg-crate" shaped foam backpanel of the Editors' Choice Mariposa great at limiting sweaty back syndrome.


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