I’ve had a handful of multi-day packs. So far, I’ve carried the Osprey Atmos AG 65 and Exos 48, Deuter Aircontact 65, and Teton Sports Explorer the longest. The former three are great long distance packs, while the Teton is my sturdy bushwhacking-in-thorns pack. All three are a little on the heavy side, ranging from three to six pounds. I like that feeling of my pack being glued to my back, so I don’t mind the extra weight.
I’ve also carried lighter packs, having borrowed a 40L HMG Junction 2400 and a 50L Six Moons Minimalist, but ultralight packs have never been my cup of tea. This preference comes down to one feature: Back panels.
It’s less about the weight carried, to me. Most packs feel good when properly loaded with the appropriate load. It’s all about heat and sweat. I prefer back panels with some serious airflow. How fatigued I feel along a hike has a lot to do with how hot I get. Being a “Hotlanta” Georgia hiker, Summer trips get Hot. My back is a huge heat-shedding surface, so I’m a big fan of the Osprey Antigravity system, as seen in the picture below, or similar mesh-backed suspension systems. Most of your big pack brands have an Antigravity-adjacent option on at least one of their packs these days, and I feel like most of them do the same job: get the solid surface of the pack off your back and circulate fresh air between you and your pack as you move.
On the other hand, most ultralight packs cut out the ventilation feature to save weight. I wasn’t a fan the HMG junction, with it’s back panel being nothing but waterproof pack wall directly against my back. It just did not fit me well to where I could get a good mid-back gap. The Six Moons Designs Minimalist was better, with foam straps and back padding lifting the pack away from the dip in the center of my back. This gives the Minimalist better airflow, but I still find the hot air getting trapped between the back panel and my back until I shift the pack around. I’ll add that I carried the 2018 Minimalist version in the picture below, and Six Moons Designs has since revamped the Minimalist into the Minimalist V2. The V2 seems to have less contact with the back when looking at images online, but I need to get my hands on one and hit the trail.
Every person is shaped differently. Your experience may differ, and I recommend trying the HMG yourself, but I wouldn’t carry the HMG Junction again myself since it seemed to stay wet up against my back as I hiked in the lukewarm temps of Fall. The Minimalist (2018 Version) was an absolutely pleasure in general, though I wouldn’t use it as my go-to summer pack. The Minimalist airflow is better than the Junction, but the 2018 Minimalist still isn’t quite for me. The Osprey Exos 48 does have the Antigravity style mesh in a lighter pack, but I’m drawing a personal line in the sand defining ultralight packs being less than 2.5lbs. Is the Exos 38 lighter than that unlike the Exos 48? Yes. Am I splitting hairs? Yes. Moving on!
Enter the Aerios 45.
This pack has all of your traditional ultralight features at 2lbs 6oz, but Arc’teryx comes out swinging with their Aeroform back panel, seen below. Is it a riff on the Antigravity type paneling? Sure. Is it totally novel in the land of backpacks? Nope. Do I care? Not a bit. The Aeroform back panel puts about a centimeter between your back and the pack wall with what appears to be a heat-formed dimpled mesh. These dimples are surprisingly strong, taking serious effort to press the panel up against the pack wall and springing right back. The moment I let go, the Aeroform panel pop back up with zero deformity.
I hadn’t found everything what I want in an ultralight pack so far, but then I put this pack on at REI on a pure whim. I came for a new filter, but left with the Aerios 45. Why? Because after dawdling around the store with first 20lbs, then 45lbs (not recommended for any ultralight pack), removing and putting on my shoes while standing, and sticking so many bottles and baubles in every pack pocket I could reach that I started being followed around by an REI employee (okay, that part didn’t happen. REI is very accommodating), I felt zero heat on my back in that 70 degree store after an hour. That needed to be trail tested.
Now, let’s be clear. I have 20 trail miles on this pack. I said Contender, not Champion. I’m impressed right now, but I have to put it through its paces. I’ve carried the Aerios in spring warm-and-breezy weather very similar to what I experienced in Fall with the HMG Junction. My findings so far: No lingering back sweat. Similar to the other mesh back panel systems, I feel a small amount of fresh air flow between my back and the pack as I move. add in not two but six total hip/strap pockets and I couldn’t get the REI dude to take my money fast enough.
Does the Aerios have everything I want? No, it’s missing a water reservoir pouch. And keep your Smartwater bottles to yourself. It’s been 14 years since my first Camelbak; you’re not changing my mind.
But, that’s it. So far, there is only one feature I want for in the Aerios 45, and I’m fine with putting my water badder on the top of my stuff. Could I reverse course completely on the Aerios? Yes. I reserve the right to change my mind, especially at 20 miles. Do I have a lot of faith in Arc’teryx based on years with their products and customer support? Yes. Does it speak volumes that this pack isn’t the least bit painful when overloaded (again, not recommended)? Yes! I am very much looking forward to carrying this pack for Summer 2022. I’ll amend this post with trip reports and additional features as I take it out, but I have a lot of confidence in this one.
Trip Report – Pinhoti Day Hike – 4/2/2022
This is definitely a comfortable pack. I packed out about 25lbs (base 16lbs) for about 9 miles on an out-and-back from the Dennis Mill trailhead. The Aerios sat snug on my hips the whole time, focusing all of the load on my hips and lower back to the point that I had no strain or weight on my shoulder, with the barely snug shoulder straps solely providing sway stability. I could loosen shoulder straps, continue walking, and feel no qualifiable difference. That’s amazing.
I am developing two gripes, though. First, the Aerios has two shock-cord style chest straps. These loosen as I walk, causing me to snug them back up once or twice an hour. It’s not a big deal and would not stop me from purchasing this pack again.
Second, though, I have an issue that may find me returning this pack. After about an hour into each hike, I’m noticing a squeaking noise that I believe is coming from the top of the shoulder harness attachment. I’ll be reaching out to Arc’teryx for a solution, as the noise is loud enough to keep me from enjoying the sounds of the forest. I’ll follow up this trip report with Arc’teryx’s response.