Spring Steel Frame, ‘Winged’ Expansion: Mountain Hardwear JMT 25L Backpack Review

In my ongoing hunt for a technical daypack that could keep up with my busy, but active, life, I came across Mountain Hardwear’s JMT 25L backpack. Named after the John Muir Trail, the JMT 25L is made from weather-resistant 210D ripstop nylon and features a 500D CORDURA bottom.

That translates to a technical daypack that is built to be dragged around, banged around, used, abused, and is not afraid of inclement weather. It looked perfect for the day-to-day uses I needed a bag for — kids’ soccer games, work, and travel. But it also featured a spring steel frame instead of a frame sheet or frameless design that most daypacks have. That, plus the “winged” side pockets made it technical enough that it could also make a reliable trail companion, I figured.

I was right. Through my testing, the JMT 25L has become the one pack I rely on for work, play, travel, being a dad, and all the other awesome and spontaneous things that pop up in my daily life. It’s perfect for my active lifestyle in the outdoors, and beyond.

In short: The Mountain Hardwear JMT 25L is more technical than a lot of daypacks currently on the market. It’s got an internal steel frame, well-designed exterior pockets and storage options, hip belt pockets, and a clamshell opening. It carries weight easily, and it’s weather-resistant and durable. There are a couple of details that leave room for improvement. But I found it perfect for almost any adventure I threw it into.

Mountain Hardwear’s JMT 25L Backpack: Review

What I Need in a Pack

In college, I used a technical daypack to get me from class, to work, to the trail, and everywhere else — all with the intention of not needing to head back to my dorm. After I graduated, I swapped out the “going to class” part for flying all over the world. But I never strayed away from a good daypack.

Now, I’m also the father of two very active girls. That means I am going to more places, without heading home, than I ever have before. Soccer. Dance. Band. At 42, I am more on the go than I have been in years. And I am unwilling to sacrifice time by having to head home just to swap stuff out of my pack.

I approach daypacks as a universal solution to get me through my day-to-day life. So, how did Mountain Hardwear’s JMT 25L live up to those expectations?

First Impressions

I did a lot of scouting and a lot of research before my sights were set on the JMT 25L. There were a few other contenders. But none of them seemed to go above and beyond what I was looking for.

I was focused on top-loading packs because I’ve always found them easier to load and unload, for the most part. But I never considered a clamshell-style opening, like the one on the JMT 25L. It functions like a top loader but eliminates the issue where the lid of the top loader flops over, making it harder to get into a pack when it’s not fully loaded. I’ve been dealing with that issue for years, but this pack eliminates it.

Front and rear grab handles make it easy to grip the JMT 25L. Load lifter straps help tadjust the pack’s weight as it’s riding on your back, and side compression straps double as areas to stash soft goods. The removable front mesh panel makes it easy to carry a helmet, sports ball, or extra layer you want to keep on hand.

One of the most notable features of this pack, though, is the flexible spring steel frame. Most daypacks feature sheet frames, or no frames at all — the spring steel frame of the JMT 25L gives it a much more technical feel. It creates tension in the back mesh, allowing for increased mobility, flexibility, and load management. This style of frame provides a more substantial structure than a frame sheet would and is not removable.

The expandable external side pockets, storage pockets on the hip belt, and the removable front mesh panel also caught my attention. Extra external storage is always better than more volume inside in my opinion. It provides easy access and places to store things that you might not want to put inside a pack — like a wet rain shell.

The Mountain Hardwear JMT 25L Backpack’s breathable mesh back panel ventilates to help dry sweat. The pack’s hip-belt has storage options for those grab-on-the-go bits and pieces like a headlamp, compass, or trail snacks. One is a zippered pocket. The other is an unzippered mesh stretch pocket.

In the Field: Day-to-Day

Testing for the JMT 25L began in August and ended in the first week of November. The weather has been mild here in Connecticut, but we did have a solid month of rain. I am also in the middle of a handful of other tests, so this pack has carried a bunch of random things at one time or another. Being that the main compartment of the JMT 25L is one large cavity, it makes a terrific catch-all for things like multiple hatchets, a solar power pack, cables, extension cords, library books, and beyond.

As I said, the JMT 25L is my everyday, everywhere backpack. I would have carried my groceries in it by now if I already didn’t have 5,000 reusable bags.

In the 3 months that I was using the pack, the weight always hovered around 25-28 pounds. Roughly 7 pounds of that was water being carried in a Gregory 3D Hydro 3L reservoir. This may seem heavy (especially for my minimalist friends). But as a daypack, on and off the trail, this was totally acceptable to me.

During that time, I logged in over 30 miles of trail time. I can’t tell you how many miles I spent walking to and from the soccer field with it, or back and forth here and there. But conservatively, I’d say this pack went through at least 50 miles of use and abuse. And every mile was comfortable.

I have an 18-inch torso and the hipbelt lands right where it needs to on the top of my hips. The bag itself follows the contour of my spine, and I can feel it moving with me — especially when the pack is full. The pack is also narrow and lives inside the span of my shoulders. So there was zero obstruction in my movement.

Going Camping With the JMT 25L

We had a good spot of weather in October where I had a chance to spend a night outdoors. It was clear and in the mid-60s with a slight breeze. At 1,526 cubic inches (25 L), the JMT 25L was sufficient for an overnight in the woods. No, it’s not big enough to carry a large sleeping bag inside or outside, even compressed. But it was well-suited to carry a minimalist camping kit, on top of my essentials:

• Tent: Durston X-Mid 1 Solid
• Sleeping Pad: Therm-A-Rest NeoAir XLite NXT
• Sleeping Bag: Sea to Summit Reactor Fleece Liner
• Stove: Jetboil MiniMo Cooking System

For this overnighter, the expandable side pockets and front mesh panel came in handy for storing soft goods and freeing up some space inside. In hindsight, I could have carried the tent and its poles in one of the side pockets. Unlike a standard side pocket, when the ones on the JMT 25L are expanded, they have a wing that can wrap around the front of the pocket, stabilizing whatever you’re carrying in it.

Just About Perfect

The two yellow loops underneath the removable mesh panel are designed specifically for trekking poles and ice axes. But with just an inch more of “loopage,” you could easily fit an axe or hatchet in them. I’ve got nothing but love for trekking poles and ice axes. I’ve got more love for a solid hatchet or axe.

The second improvement I would like to see is making the unzippered storage pocket on the right hip belt zippered like the one on the left. I like the idea of a stretch pocket when I am on the trail, but for hauling the bag around, especially when traveling, it’s more risky than what it’s worth.

Different Versions of Mountain Hardwear JMT 25L Backpack

The JMT 25L comes in both men’s and women’s sizes. Aside from the men’s version being Black Spruce and the women’s version being Northern Blue, the differences between the two packs are minimal but specific. The women’s version of the JMT 25L has shoulder straps and a hip belt contoured to a women’s-specific shape. Also, the size ranges on the torso and hip belt are smaller than on the men’s pack, but only by an inch or two.

Otherwise, the two packs are made from the same materials and have the same features. This review could easily relate to either version of the JMT 25L.

Additionally, for those of you looking to extend your adventures out a few more days, Mountain Hardwear offers a 35L version of the JMT as well. That model, which features an adjustable frame, is available in two men’s versions as well as two women’s versions based on torso size.

Mountain Hardwear JMT 25L Backpack: In Conclusion

Mountain Hardwear’s JMT 25L is a well-built and adaptable daypack. The steel spring frame is a feature more often found in multi-night backpacking packs and makes this a more technical piece of gear. The expandable winged side pockets are also a unique feature that improve the storage options. Though this bag came out in late 2022, it easily hangs with GearJunkie’s Best Daypacks of 2023.

If you’re a backpack fanatic like me, this is an adventure daypack that you’ll fall in love with. It could also be the pack that you haul out of storage when your kids get older and decide to go hiking, trekking, traveling, and living that outdoor life you haven’t shut up about since they were toddlers.