Background

As my KS 4 review makes clear, I am a huge fan of that handy little rucksack made by KS Ultralight. However, when plans to packraft the Greater Patagonia Trail solidified last summer, I knew that I would need something with more volume and load-carrying capacity.

So, as every gear-obsessed, devout Ultralighter does, I researched the backpack market ad nauseum and found that when it came to packrafting, there were essentially two options: the Hyperlite Porter and ULA Epic. Neither of those options excited me, so I emailed Laurent at KS Ultralight to see what he could do. While not marketed as a “packrafting backpack,” Laurent recommended the KS Ultralight R-50, which his website describes as “a minimalist design for maximum toughness.”

I ordered my R-50 in the fall of 2017 with the following features:

• Side water bottle pockets

• Custom bottom webbing strap placement (moved slightly up to accommodate the water bottle pockets)

• Roll top closure with 20 millimeter daisy chain on the shoulder straps (replacing the default Joker Hat Top Closure system)

• 20 millimeter top Y-strap (for lashing my packraft)

• Removable fabric front panel

• Removable frame set

• 53 centimeter torso

In addition, my partner on the trip, K, also purchased an R-50 for our GPT trip. I’ll include her observations in this review, but note that her R-50 had slightly different features:

• Side water bottle pockets

• Custom bottom webbing strap placement (moved slightly up to accommodate water bottle pockets)

• Roll top closure with 20 millimeter daisy chain on the shoulder straps (replacing the default Joker Hat Top Closure system)

• 20 millimeter top Y-strap (for lashing her packraft)

• Navy VX-21 fabric

• Removable fabric front panel (Navy VX-21)

• Removable frame set

• Two removable hip belt pockets

• 47 centimeter torso

My R-50 weighs exactly 24.15 oz on my scale, including all removable features.

Overview

In the four months spent hiking and packrafting along the Greater Patagonia Trail, I put the R-50 through the gamut. It carried 35+ pounds regularly. The VX-21 fabric was tested with off-trail travel and bushwhacking. My pack was lashed to the front of my packraft and soaked daily.

From this experience, I found the R-50 to be an extremely durable pack full of simple, ingenious features that makes it excellent for packrafting. True to KS Ultralight’s philosophy, the R-50 has everything I need for an adventure pack, and nothing more. In fact, I think the R-50’s flexibility is its greatest strength; with removable external storage, frameset, and hip belt pockets, as well as a plethora of attachment points, this pack can be used for anything from rock climbing to cross-country sking—it really is a jack of all trades. However, I also found limitations with the hip belt and frameset, and these drawbacks curtail the pack’s possible applications.

Size

The R-50 has a slightly trapezoidal shape, with a narrow bottom that grows wider near the shoulders and opening. It has a curved bottom, which makes calculating the exact volume nearly rocket science. My R-50 is atypical due to the roll-top collar, but I measured its dimensions to be 10.25 x 7.90 x 31.50 inches, or approximately 42 liters in size. KS Ultralight claims the pack is “adjustable up to 45 liters” in volume.

For some people and applications that require a lot of gear, this might be too small. With options such as the back panel, generous hip belt pockets, and good sized water bottle pockets, I was able to pack nine days of food and a full packrafting setup.

Durability

After four months of use, the VX-21 fabric has held up great. Neither K’s or my R-50 has any tears or holes, and the laminate doesn’t show signs of peeling or fraying. K’s blue VX-21 has a slightly faded color from the sun, but that’s an aesthetic change and doesn’t affect performance. The shoulder straps are wider on the R-50 than on my KS 4, and as a result they seem to compress less. The hip belt is still plenty thick and I anticipate that this pack has many miles left in it. All the stitching is still solid—I can’t find any ripped or torn seams.

Packrafting

This section isn’t so much a review as it is an argument: the R-50 is a great packrafting backpack. Although KS Ultralight doesn’t advertise the R-50 for packrafting (unlike the Hyperlite Porter and ULA Epic), it contains many of the same features. For example, the floating rear panel is similar to the ULA Epic’s system, and the rear daisy chains are nearly identical to the Hyperlite Porter. These features provide ample attachment/lashing points when tying the pack down to a packraft, as well as an easy way to secure wet gear to the outside of the pack. The R-50 is made out of VX-21, a laminate which doesn’t absorb moisture, thus allowing the pack to dry quickly.

Plus, the R-50 tops other packrafting backpacks in two important categories: weight and customizability. At just around 1.5 pounds, the R-50 is at least a half pound lighter than other packrafting packs. This is due in part to KS’s minimalist design approach as well as the packs smaller volume. With respect to customizability, KS makes it possible to design a pack tailored specifically for your gear. For example, by pairing a fabric back panel to store our wet gear with Y-strap on top to store our rafts, we could go from land to water without even opening our backpacks and in less than 10 minutes (especially useful in the rain).

Optional features

Removable Back Panel

For my pack, I had custom removable back panel made in VX-21 instead of the default mesh for additional abrasion resistance. The panel is attached to pack on three sides by shock cord, which can be loosened or tightened to increase or decrease storage capacity, respectably. This floating system I found just as secure as a normal backpack’s back pocket, but providing far more flexibility and volume. With the shock cord fully loosened, I could fit close to ten liters of gear in the rear panel.

One benefit of this floating panel is that you can often pull out objects in the bottom of the rear panel without having to take out everything else first (like you would with a normal backpacking pocket). I found this particularly useful when grabbing snacks or sunglasses while rafting. Because the panel isn’t sewn in, I was initially concerned that things would fall out, but I have found that the panel tensions easily and holds contents quite securely. Neither K nor I have ever had anything fall out.

Hip Belt Pockets

While the hip belt is standard, K got two removable hip belt pockets and I want to touch on both features very briefly.

I found the hip belt to be well cushioned, but slightly flimsy. It’s also a fixed size, so very skinny people might have trouble tightening it far enough. The hip belt is comfortable to wear.

With respect to the removable hip belt pockets, they’re huge! Each one has roughly one liter of space, which provides plenty of room for storing a phone, camera, small valuables, first aid kit, and snacks. They come with waterproof YKK zippers, and while the pockets themselves are not waterproof (the seams are not taped), K found the pockets to be highly water resistant. The attachment hooks and webbing are well designed, making it easy and secure to attach and detach the pockets. While the extra hardware creates possible failure points, these are by far my favorite hip belt pockets. K’s set weighs 2.50 oz total.

Removable Frame Set

KS Ultralight’s frame set—two simple carbon rods that run vertically from each side of the hip belt to a sewn in velcro lashing point is so simple, lightweight, and effective that it makes you wonder why all companies don’t do the same thing. As long as you measure your torso correctly, the frame set transfers weight from the shoulder straps to the hip belt.

That said, such a simple system does have its drawbacks. On K’s pack, one of the velcro fittings that locks in the frame has lost some of its “stickiness.” Especially toward the end of our GPT adventure, her frame would occasionally pop out of the velcro. Over time, as the velcro gets dirtier, I expect this annoyance will only increase. I wouldn’t recommend removing and reinserting the frames frequently for exactly this reason. In retrospect, I might have had Laurent sew the frames directly in instead of using velcro if I didn’t plan on removing them.

Secondly, because the frames are straight, when weight is transferred to the hip belt, the pack has a tendency to fall away from your upper back due to the natural contour of the spine. See the picture below for a better idea:

Conventional wisdom says that holding the pack in closer to the torso provides for a better carry. In practice, the straight frame does add a small amount of strain on the front of your shoulders, and a pack that rests closer to your shoulders feels more snug. On the flip side, one unintended benefit of this gap between the pack and back is that it creates good ventilation.

Conclusion

KS Ultralight has made a bomber, versatile backpack ideal for a plethora of uses in the R-50. To find such a rugged pack weighing under a pound and a half is impressive. The most popular backpack I know of in the R-50’s weight class is the ZPacks’ Arc Blast, but comparing the two is like comparing apples to oranges. The R-50 is a durable, multi-functional adventure pack, not a one-and-done thru-hiking pack like the Arc Blast.

For these reasons, the R-50 is my go-to recommendation for a bomber, do-it-all, ultralight backpack. The pack is on the small side in terms of volume, but with all the flexible, external attachment options it can easily be expanded to fit more gear. KS Ultralight’s biggest fault is only marketing the R-50 as good for “climbing, hiking, bushcraft, military, winter sports, skiing, snowboarding, snowshoeing, long adventure trips, travel, and duffel bag style use”—It’s also great for packrafting!