Thriller Ranch Radix Backpack Assessment: Thriller Ranch Goes Mild

If you’re familiar with Mystery Ranch, you probably wouldn’t use the term “lightweight” to describe the packs made by the Montana-based brand — especially those products in the hunting and emergency service lines.

So, let’s be clear from the start: The Mystery Ranch Radix is the brand’s most lightweight backpack yet. The 57L version I tested weighs 3.78 pounds empty with all the bells and whistles. Or, strip the pack down to its bare bones and it’s just 3.02 pounds.

Is it an ultralight pack? Mystery Ranch is calling it a “lightweight” pack with ultralight features. It isn’t nearly as light as some packs from GearJunkie’s Best Ultralight Backpacks roundup. Most of those are sub-3 pounds.

But it’s lighter than a number of other lightweight, but non-ultralight backpacks; including the REI Co-op Traverse 60 (S 58L) at 4.19 pounds ($230), Gregory Kalmia 60 (S/M 60L) at 4.49 pounds ($310), and Deuter Futura Air Trek 50+10 (60L) at 4.52 pounds ($250).

So, with its first foray into lightweight backpacks, Mystery Ranch seems to have hit the mark — at least, in terms of weight. But how would the backpack perform on my back hiking out into the backcountry? While the pack won’t be publicly available for purchase until January 2024, I got hold of a sample to put Mystery Ranch’s first lightweight pack to the test.

In short: The Mystery Ranch Radix Backpack ($299) is a lightweight, comfortable, and hauling-savvy backpack to support multinight, long-distance backpacking adventures. It’s on the pricier end of the spectrum — but not by much. It’s extremely customizable to suit a wide range of use scenarios and comes with a men’s- or women’s-specific harness fit.

The Radix is also available in 47L and 31L versions. Mystery Ranch has pulled this lightweight pack off. And it didn’t sacrifice any of the durability or design features the brand is known for.

Mystery Ranch Radix Backpack Review

Overview

The Mystery Ranch Radix Backpack harness system is simple, and I feel that’s the success of it. The shoulder straps are padded but not overstuffed. The adjustable back panel is modest, and I often felt a breeze push through there to help keep me cool while testing this lightweight backpack. The waist belt is moderately padded to keep it from being bulky.

On my test trip, I wanted to take advantage of the lightweight nature of the backpack itself. So, I managed to keep my base weight at 30 pounds. Not surprisingly, I never had any comfort issues. With the hauling heritage of Mystery Ranch, the harness and pack can certainly take a much heavier load and relative comfort will adjust accordingly.

I used the men’s small/medium-size harness, which adjusts between 15 and 20 inches along the torso. The adjustment is held by the commonly used hook-and-loop attachment. It comes with an integrated curved plastic panel to break the hooks away to customize the fit.

The load lifters, shoulder straps, and waist belt were all easy to adjust on the fly while wearing the pack. I took advantage of shifting the weight of the pack around throughout the trip — especially as we tackled a steep scramble section of the trail along a beautiful waterfall.

The Mystery Ranch Radix Backpack series comes with a bunch of great features and access options. It’s made with technical Ultra-PE Birdseye and recycled 100D Robic Ripstop fabric. Pretty much any part of the pack that is not the body itself can be stripped off to save weight.

Mystery Ranch Radix Harness

The entire upper back panel, which is attached to the shoulder straps, can be removed to swap between the men’s and women’s specific harness. The Radix comes with zippered pouches on both sides of the hip belt.

While the pockets cannot be removed themselves, the entire waist belt can. Instead of being one big piece that runs behind the back, each side is removed separately.

I found this design allowed for each side of the hips to move and flex independently when I was scrambling and needed to bend or twist a certain way. Yet, while just hiking along the trail, the individual sides of the hip belt worked together and provided the stability of a single piece.

At the nape of the neck, I appreciated the large and sturdy lift loop for when I was putting the lightweight backpack on or taking it off. It also served well for hanging the pack on my hammock line to keep it out of the dirt and position it to be easier to reach inside.

Between the lift loop ends is the hydration hose pass-through. It can accommodate either the left or right side.

Mystery Ranch Radix Top

The clamshell top is easy to remove with two clips. It has plenty of webbing to stay on top of an extra-tall load sticking out of the top of the pack. Interestingly, while the front and rear clips are female and male, respectively, they are not the same size. That means you can’t clip them together to make a sling-bag daypack on its own. We won’t deduct points for that, but it would be a handy feature.

The long straps from the face of this pack are removable and make for a good carry system. The top of the clamshell has two parallel strips of webbing tacked down to three daisy loops for clipping or attaching extra items. I see this as a great place to dry clothes or rainflies for longer trips.

The 270-degree water-resistant YKK zipper of the clamshell brain has large orange pull tabs so they’re easy to spot. They’re also easy to reach while wearing the pack for on-the-go access.

The large space inside the unit has a mesh zippered pocket lined on the inside of the top section. This includes a key leash and is a great spot for a SOAP Notes notebook and other emergency access-only items. And, yes, I’m an ex-mountain search and rescuer, so I still think about these things on each of my outings.

Storage, Straps, and Access

Pockets

Three bellowed pockets on the outside of the pack are its most noticeable feature. The side pockets have a slanted opening on the top and an elastic drawstring cinch.

I used these pockets for my folding sit pad and my 0.75L LifeStraw flexible water bottle. The cinch cord provided confidence in keeping the water bottle secure. The two removable cross-bag straps held the sit pad in place, but kept it easy to access for (slightly more comfortable) stops along the trail. These pockets could also accommodate wands, snow pickets, and tent poles.

The large pocket on the back fulfilled all my stash and instant access needs. Fortunately, it didn’t rain (much) on my trip. But, I had my rain gear in there nonetheless. It was also a handy spot to shove my morning layer after warming up while climbing a few hundred feet toward the continental divide.

All of these pockets have drain holes. The rear pocket is a grommet hole, and the side pockets have an unstitched corner at the front of the pack/pocket. At first, I thought this would be a pretty annoying place to have water draining right onto my heels. But then I realized if it’s so wet out that water is streaming out of there, wet heels would probably be the least of my concerns.

Straps

Another key feature on the exterior of the Radix is the set of horizontal cross-body straps. Both of these straps wrap a full 270 degrees from one side across the back and to the other side. The straps are attached using a lark’s head (or crow hitch) knot to a loop stitched into the vertical seam of the body of the pack. There are actually 10 of these tie-down loops scattered strategically around the body of the pack.

On the sides of the pack, these straps can serve to hold longer items like snow pickets which stick out of side bellow pockets. Both straps have side-release buckles and plenty of webbing to wrap around large items. The lower strap is 8 inches above the bottom of the pack. Both the side and rear bellow pockets have pass-through points so the strap can either run on the inside or the outside of the pockets.

The upper strap is 9 inches above the lower strap. I’m curious to see how these straps do holding skis in an A-frame carry this winter. This pack (the 57L version) would be a good size for a winter backcountry hut trip. When not in use, you can remove both straps completely.

The bottom of the pack hosts a set of forward/aft parallel straps — a classic spot for a closed-cell foam sleeping pad. Also on the bottom are two 4-inch ice axe or trekking pole carry loops. They have orange elastic handle straps just above the upper cross-body straps. Neither the pad straps nor the ice axe loops and cords are removable.

Inside Access

To get inside the Radix, Mystery Ranch has a drawstring closure scrunch top as well as — in true Mystery Ranch style — a single rubberized water-resistant YKK zipper that runs the full height of the pack body.

My only wish was this zipper had double pulls. That way, I could open the bag from the bottom instead of having to unzip it completely to get to something small at the bottom of the pack.

Mystery Ranch Radix Interior

The inside of the Radix is a simple large compartment. There are eight orange reflective loops where the sold-separately Mystery Ranch Quick Attach Zoids pouches can be attached for more organization.

Otherwise, the only pocket feature in the Radix is a 5.5-inch wide by 11-inch deep pleated sleeve. It runs from 11 inches below the top of the frame of the pack to the bottom. According to Mystery Ranch, this is for — what would have to be — a very skinny hydration bladder. It’s also where the removable 7000 Series, aerospace aluminum frame tucks in.

For water storage, this sleeve is great for keeping the water weight low in the pack. But it’s horrible for on-trail refills. I would guess 90% of the contents of the pack will need to come out to get a freshly filled hydration bladder back into that sleeve. There’s also a toggled cord hanging from the top of the compartment to hold a hydration bladder upright.

Also on the interior of the pack, right at the top of the frame, is a 5/8-inch strap. That strap runs from the back to the front with a side-release buckle at the front. This could be used to secure a rope over the top of the pack load, with or without the clam top connected, or to just cinch the load in a bit more.

Mystery Ranch Radix Conclusion

To put it simply: I really liked this lightweight backpack from Mystery Ranch. The simplicity of the harness, the convenience of the pockets — on the hip, in the lid, and the big bellow pockets on the sides and back — and the ease of access all worked very well for me during testing.

The fabric and the construction are in line with the durability that customers have come to expect from Mystery Ranch. And, I have high confidence that it will also do well in the winter for ski touring trips.

However, the Mystery Ranch Radix Backpack won’t be available to purchase until January 2024. You can sign up for a reminder on the brand’s website.