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How We Tested Ultralight Backpacks

Tuesday July 18, 2023

As always, we subjected the backpacks we tested to a battery of laboratory testing and logged many trail miles with each. Our unique testing process at GearLab 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.

ultralight backpack - loading up a pack with awkward payloads is a devious way to find...
Loading up a pack with awkward payloads is a devious way to find weaknesses in pack design.
Credit: Justin Simoni

Comfort


What's the point of a featherlight backpack if it's not comfortable enough to wear for days, weeks, or months at a time? Finding yourself six hours into a trip with sore shoulders, an aching back, and bruised hips is a nightmare way to start any adventure.

ultralight backpack - early spring trips mean bringing heavy loads and navigating variable...
Early spring trips mean bringing heavy loads and navigating variable terrain - perfect proving grounds for us to tests how comfortable a pack is.
Credit: Justin Simoni

This metric covers those pain points so that you can avoid them yourself. We test each pack on how it carries various-sized loads by taking all these packs out with smaller 15-pound all-day kits and 30-pound multi-day kits to see how they handle.

ultralight backpack - this hip belt feels great worn snuggly on our lead tester's narrow...
This hip belt feels great worn snuggly on our lead tester's narrow hips. The adjustable webbing also affords plenty of flexibility when it comes to customizing comfort and fit.
Credit: Justin Simoni

We evaluated if the shoulder straps helped carry and stabilize the load or if they seemed to be digging into our shoulders on each step. We considered if the weight of the pack transfers down into the hip belt through the frame effectively. We also tested if the packs were still comfortable after we removed various components.

We tested all the packs in the ultralight backpack roundup in their natural habitats to see how they performed.
Credit: Justin Simoni

Trips in the field helped illuminate the strengths and weaknesses in each pack's design, comfort, and load carrying. We encountered situations we'd never considered and couldn't emulate testing in the lab. We took each of these packs on multiple trips out onto our favorite trails.

ultralight backpack - we found watermelons an excellent prop to use as added ballast...
We found watermelons an excellent prop to use as added ballast during our weighted comfort tests.
Credit: Justin Simoni

Ease of Use


For ease of use, we evaluated how easy, usable, and functional each of the packs' features were. Are features present to only check a box, or do they deliver a better experience to the user?

ultralight backpack - a wide top opening and stiffer fabric make it easy to place bulky...
A wide top opening and stiffer fabric make it easy to place bulky items, like bear canisters, in the pack as well as grab items already found within.
Credit: Justin Simoni

Weaker products in the ultralight category find the need to compromise on the user's experience in an attempt to hit a specific weight. Instead, a well-designed ultralight pack will be both featherlight while delivering features and usability via careful design and engineering to deliver the most impactful features.

ultralight backpack - these simple elastic bottle holders are available on the shoulder...
These simple elastic bottle holders are available on the shoulder straps, but we didn't feel that they kept the bottles stable enough when hiking.
Credit: Justin Simoni

We'd rather a feature be missing than half-baked and that the product has a clear design direction they're going for rather than trying to appease everyone just to make a sale.

ultralight backpack - this well-designed and easy to use center pocket is spacious and...
This well-designed and easy to use center pocket is spacious and made of a breathable mesh material to allow you to stow wet gear to dry out securely to your pack while hiking.
Credit: Justin Simoni

Individual features like the main pack body, interior pockets, various exterior pockets, and top lid are just some of the more important features we're evaluating.

ultralight backpack - some backpacks can adapt to an incredible range of body types with...
Some backpacks can adapt to an incredible range of body types with highly adjustable hip belts and shoulder straps.
Credit: Justin Simoni

Weight-to-Volume Ratio


We measure the volume of each pack independently using a variation of the ASTM ball test with ping pong balls. We measured the volume of the main pack and the volume of all exterior pockets. And to top it all off, we've used the same method across all our backpacking backpack categories, so you can easily see which packs are worth their weight.

We created a volume-measuring cylinder using a 1-liter measuring...
We created a volume-measuring cylinder using a 1-liter measuring container and a lot of water.
The Mountain Laurel Designs Exodus 55L gets its internal 55 liter...
The Mountain Laurel Designs Exodus 55L gets its internal 55 liter volume specification only when you fill up the bag without rolling the top.
We calibrated our testing materials and measured each pack we tested to see where manufacturer claims were real and where they were fantasy.

To make a fair comparison, we meshed this data with our digitally measured weights for each pack. If elements of a pack are designed to be removed, we weighed each element separately.

Depending on the weight of the load you want to carry, you may opt to go without parts of your pack to save some grams. Or utilize parts of your kit instead of what comes with the pack. For example, some models allow you to use your sleeping pad as your pack's back pad.

The Gorilla is modular, allowing you to separate and use the main...
The Gorilla is modular, allowing you to separate and use the main pack body apart from the hip belt, back padding, and metal frame.
The Granite Gear Crown3 60 is fairly modular, allowing you to wear...
The Granite Gear Crown3 60 is fairly modular, allowing you to wear the main pack body without the lid, hip belt, or frame. The padding cannot be removed from the main pack body. The main pack body alone weighs 26.5 ounces/752 grams.
The Granite Gear Virga 2 doesn't have back padding or a frame, but...
The Granite Gear Virga 2 doesn't have back padding or a frame, but you can remove the hip belt and a few small accessories. The main pack body alone weighs 22.2 ounces/629 grams.
The Mountainsmith Zerk 40 can be worn without the back padding or...
The Mountainsmith Zerk 40 can be worn without the back padding or light hip strap. The main pack body alone weighs 22 ounces/627 grams.
We broke down each pack into its components and weighed each one.

Finally, we compared the ratio of the weight of each pack to its volume. With this ratio, we can better compare pack weights across a spectrum of volumes to help you find the pack with the features you want at the lightest relative weight.

Replace the included back padding with your own closed-cell foam...
Replace the included back padding with your own closed-cell foam sleeping pad to free up some internal space and shed a few grams.
Swap out the included back padding for your own sleeping mat to save...
Swap out the included back padding for your own sleeping mat to save on grams and interior space!
Some ultralight packs allow you to swap out the included back padding with your own closed-cell foam sleeping pad.

Adjustability


When we talk about Adjustability in ultralight packs, we're looking at a few important attributes. First, we look at how well the pack adjusts to the wearer's body. Are the shoulder straps adjustable and comfortable? Are there load lifters for when your total pack weight varies through a long haul as your food supplies dwindle? Does the back padding and framework with you, or are you constantly fiddling and fighting to have it rest nicely on your back? Does the hip belt cinch down well, or is all the weight still on your shoulders? Can it tighten down to a smaller size as you lose your 9-5 office weight and become a chiseled state-traversing trail monster over the course of the summer?

ultralight backpack - some smaller-capacity packs make them excellent all-day options for...
Some smaller-capacity packs make them excellent all-day options for mountain adventures, fastpacking, and very dialed-in ultralight adventures.
Credit: Justin Simoni

We also consider how well the pack can be malleable to work on various adventures. Can you reasonably use the same pack that works impressively for a seven-day trip to also work for one long day in the mountains? Can you strip down the pack of unneeded features and weight if you want to go for a quick overnighter, then put back those components next month for a cross country thru? Can you easily lash on gear mid-route to help load out a buddy's kit or bring some extra provisions for an especially challenging section? Will a pack that rides well with a ten-pound load feel passable with a 30-pound load?

ultralight backpack - cinch straps on the main pack body a pack help add versatility for...
Cinch straps on the main pack body a pack help add versatility for long thru hikes as well as shorter day trips in the mountains.
Credit: Justin Simoni

We also tested each pack to see how well they packed up and carried typical gear. What are your options when carrying snacks, water, a bear canister, and a phone/camera? Are there obvious pack homes for these items, or do you have to get clever? Would it be better to purchase additional accessories, and are those accessories readily available from the manufacturer?

ultralight backpack - some shoulder straps can accommodate an incredible range of both...
Some shoulder straps can accommodate an incredible range of both torso height and width.
Credit: Justin Simoni