Backpack Decision Time – Go With The Tried And True Osprey Atmos 65 Or The New Mountainsmith Zerk 40?

Last year I saw an announcement from Mountainsmith / The Trek that there was going to be a new “fastpack” available via Indie Go Go – the Zerk 40. Co-designed by the Real Hiking Viking, who had a whole bunch of long distance hikes under his belt, it was touted as the ultimate thru-hike pack. Lightweight, large enough with a 40 L capacity to carry everything a lightweight or ultralight hiker would need, but best of all, quick and easy access to water, snacks and other knickknacks needed throughout the day, so one wouldn’t have to stop and remove their pack to get to whatever they needed. I found out about it too late to get it at the early bird price of $100, but I was able to jump in and get one for $125 (these won’t be available until July 2019, but those that bought them through the Indie Go Go sale just received them in April). I was pretty happy with my Osprey Atmos 65 in nearly every way, except weight (it’s heavy) and capacity (65 L is a bit much). However, at just $125 I thought it’d be worth picking up a Zerk 40 to see how I liked it, and how it would work with my current gear.

I received it a couple of weeks ago, and had a chance to do a quick day hike, loading it with some extra stuff I knew I wouldn’t need to add some weight to it. First impressions were good – it seems strong, I like the rolltop access to the main compartment, and there are tons of pockets – double water bottle pockets on each side, pockets on each shoulder strap, and a huge, stretchy pocket on the back. I put it on and was immediately impressed by how it fit – it was comfortable, primarily due to the wide shoulder straps that take the bulk of the weight (as opposed to my Osprey pack, where weight is distributed to the hips). For heavy loads I think it’s probably better to have weight on the hips, but for a lighter pack I like the wide shoulder strap approach. In any case, the quick hike went very well – I barely felt the pack and I loved the large shoulder strap pockets and easy access to water.

My next test was to take the gear I had on the 2.5 week Chinook Trail hike I did last October, and see if it would all fit into the Zerk 40. Long story short, it didn’t all fit. Not even close. While I didn’t necessarily need 65 L of capacity, I probably needed 50-55 L or so. However, there were a few things I could ditch or downsize. I traded out a bear cannister for a food bag, ditched the camp shoes and sun umbrella, and took out a few other odds and ends. By doing all of that I was able to eventually get everything to fit, and probably could have added a few other small items if I needed to. However, the one thing I didn’t add to the pack was extra water beyond two Smartwater bottles – if I needed more than a couple of liters of water I’d probably struggle to get it in there. The real test though was to see how it felt with the pack on – it felt okay. At about 18 pounds it was fairly heavy compared to what most thru-hikers carry, but it is rated for up to 30 pounds and there is no way I’d want this on my back with 30 pounds of stuff in it. I’d be beggin’ for my Osprey. So having it on in my living room felt okay with 18 pounds of stuff in it, but I’d really have to take it out on a hike of 5-10 miles or so to truly test it for comfort. My plan is to give it a try on a few overnighters this summer and see how it does.

On the flip side there is my Osprey Atmos 65 pack – it is a great, solid and dependable pack that I’ve had for over a year now, and put about 350 miles on it. Amazingly it still looks, and almost smells, brand new. In all of my hikes so far I have included the brain, but this year I have removed it for weight savings and reduced capacity (I just don’t need that much capacity). For comparison sake I took everything out of the Zerk 40 and put it in the Osprey – there was obviously lots of empty space (perfect for extra water), but the true test was to see how it felt with 18 pounds of stuff in it. As I suspected, it was much more comfortable – since the pack weighs over 2 pounds more than the Zerk 40, the total weight was close to 20 pounds.

I don’t have any long hikes planned this year, primarily just overnight trips. My plan is to use the Zerk 40 as much as possible this year to thoroughly test it out. I suspect that for quick trips it’ll be easy to get the weight down to the 12-14 pound range and it should do quite well. For any future long distance hikes though, I think my plan might be to go with the Osprey, and just do what I can to minimize the load. It’s super comfortable, has great ventilation and with a lighter overall weight I think it’ll be the pack to go with for longer hikes.