The world's most in-depth and scientific reviews of outdoor gear

How We Tested Ultralight Backpacks

By Jane Jackson & Brandon Lampley
Thursday April 4, 2019

As always, we subjected the 15 backpacks we tested to a battery of laboratory testing, but also logged a lot of trail miles with each. Our unique testing process here at OutdoorGearLab means we purchase all the products we test, scrutinize them in the lab, and play hard in the backcountry to give you the straight scoop.

The results of our independent pack volume testing and our weight measurements. We feel weight to volume ratio is a great way to compare packs of slightly differing volumes. As you can see in the final calculations a lid or 'brain' for a backpack can be a convenient feature for some users but doesn't deliver much volume compared to the weight it adds.
The results of our independent pack volume testing and our weight measurements. We feel weight to volume ratio is a great way to compare packs of slightly differing volumes. As you can see in the final calculations, a lid or 'brain' for a backpack can be a convenient feature for some users, but doesn't deliver much volume compared to the weight it adds.

Volume


Nominally, these packs are described as certain volumes by their manufacturers, but based on use, we knew these numbers aren't comparable between brands. To get a good comparison point, we wanted to measure the volume of each pack independently. To achieve this goal, we devised our variation of the ASTM ball test, and we measured both the volume of the main pack and the volume of exterior pockets. To make a fair comparison, we meshed this data with our digitally measured weights for each pack. Find the detailed results of this test and our calculations throughout this review. Also, when our lead tester packed up for a big wintertime section of the Appalachian Trail, he packed that 13-pound base weight load along with five days of food and fuel into each pack. Lab measurements plus real-world side-by-side testing…that's our secret sauce.


Weight


Our expert testers could be accused of being gear geeks. That's okay…we play very hard, and equipment is essential. On every trip out with these products, we first got out a scale and noted the weight that we had packed in each model. Also, towards the end of our testing, we loaded each pack with two test loads (15 lbs and 30 lbs) and did some hot laps up and down and around the farm. We're confident we have performed the most thorough direct comparison of load carrying comfort ever done.

At the end of our testing we put the three award winners through some grueling winter trips. Brandon banged out 260 miles on the Appalachian Trail in the first two weeks of January first using the Arc Blast and then switching to the Gorilla for the Smoky Mountains. The Exos 48 saw him through an awesome 40 miles off trail trip through Colorado's Black Rock Canyons Wilderness earlier in the winter.
At the end of our testing, we put the three award winners through some grueling winter trips. Brandon banged out 260 miles on the Appalachian Trail in the first two weeks of January, first using the Arc Blast, and then switching to the Gorilla for the Smoky Mountains. The Exos 48 saw him through an awesome 40 miles off trail trip through Colorado's Black Rock Canyons Wilderness earlier in the winter.

Features


On top of this, we carefully scrutinized each pack's features. Does the waist belt have a 2:1 tensioning system for quick tightening? How much can you fit in the waist belt pockets? Will a JetBoil stove fit in the side pocket? Just how many Clif bars will fit in that waist pocket? While the scope of our reviews doesn't allow us to describe every single feature of each pack, rest assured we scrutinize the fine details when awarding scores. And finally, in addition to our durability observations during testing, we surveyed our extended group of rockstar thru-hiker friends and testers. If anyone has experienced a durability issue with any of these products, we wanted to know.

For scenery adventure and challenging conditions this trip through Colorado's Black Rock Canyons Wilderness area delivered. This pack was a great companion along the way.
For scenery, adventure, and challenging conditions, this trip through Colorado's Black Rock Canyons Wilderness area delivered. This pack was a great companion along the way.