KS Ultralight Gear KS50 Backpack Review

Perennial Favourite Among Lightweight Backpackers

KS ultralight gear is one of a growing number of cottage companies serving the needs of ultralight backpackers both here in Japan and around the world. It’s run by French expat Laurent Barikosky who has been fabricating lightweight and durable backpacks for hiking and climbing from his home base in Komaki City north of Nagoya since 2009. What differentiates Laurent from most of his contemporaries is his widely customisable packs. In essence you begin with a bareboned frameless pack in the case of the KS50 starting at 380 grams (13.4 oz) adding options to your heart’s content – budget permitting that is. It is recommended for base weights up to 4 kg and a load limit of 12 kg.

Since receiving my KS50 pack back in the spring I have put it through its paces on quite a few day and overnight hikes and feel ready to shares my thoughts.

KS ultralight gear KS50 backpack with 200D Spectra diamond ripstop.

First Impressions

It’s light! While this might seem rather obvious my previous Montbell pack was closer to 2 kg, so the weight difference was very apparent. As I touched on above the KS50 like the three other KS pack volumes comes with an array of add-on options – no less than 25 in fact. I picked 10 of them delivering a final pack weight of 630 g (22.22 oz). Most of this additional weight is attributable to ‘comfort selections’ such as the back with 3D spacer mesh 60 g, internal pad pocket with removable 8 mm white Polyethylene foam pad 37 g, anatomic padded hip belt 40 g and removable frame set adding 60 g. Combined these four add-ons comprise 80 percent of the option weight. While my base weight hovers around 5 kg (11 bs) hiking in Japan often necessitates carting water long distances thus I want to do that as comfortably as possible.

Regarding pack fabrics KS ultralight gear offers a good selection. For the pack body I went for 200D Spectra diamond ripstop as its fairly abrasive resistant and X-Pac VX07 Blue for the front pocket with strong mesh at the bottom to drain water. While the 200D ripstop and 330D Cordura is water repellent the pack itself isn’t waterproof as the seams are not taped or sealed. For inclement weather conditions it’s necessary to use a pack liner or dry bag. It seems a lot of folk opt for the stock nylon mesh for the front pocket but having fabric offers better protection in turn allowing a greater range of items you can stow such as your camera and sunglasses. By default, 330D Cordura nylon is used for the bottom, shoulder strap, padded waist and side pockets for durability and longevity. The workmanship overall is impeccable with double and even triple stitching to reinforce areas subject to stress or additional wear such as the hip belt, shoulder harness, and webbing.

Given there are so many options and that navigating the website isn’t all that intuitive I strongly advise taking your time especially if it’s your first time buying a customised backpack. To simplify the process this reddit user has nicely summarised the KS50 options in a spreadsheet. If I had any questions, I emailed Laurent who is easy to work with, and responded promptly to my questions. The manufacturing lead time varies (for me it was 3 weeks) and currently sits at about 1-2 weeks plus 5 to 15 days for international shipping.

Custom front pocket with fabric stripe at top X-Pac VX07 Black.

Determining Your Pack Size

Sizing seems to be a vexed point when it comes to ordering a KS pack, at least according to some Reddit users. To calculate your correct torso length Laurent outlines three methods including measuring from the C7 vertebra to the top of the hip bone and adding 3 cm; using the length of your current backpack as a guide along with a rough height chart. Using these methods, I found my torso length is 48 cm (19 inch), backpack measured 47 cm and I’m 171 cm. Having read the packs run a bit short I opted for the 50 cm pack which fits fine although next time I would probably ask Laurent to make it a centimetre longer. In short be diligent about your measurements and if you are 5’11” don’t order a 47 cm pack like this redditor almost did.

Anatomic padded hip belt with side load lifter straps.

Organisation and Storage

The longest hike I’ve done so far with the KS50 is 3 days and had no trouble packing everything I needed. In the future I intend to use this pack on Japan’s toughest multi-day hike that is a full-length traverse of the entire South Alps from Hirogawara to the Akaishi Onsen Shirakaba-so hot spring which takes about a week. The pack’s main compartment measures 28 cm x 20 cm and with the collar fully opened its 80 cm long which is plenty, and the unused capacity can be rolled and securely cinched down using the top closure strap. If you’re after extra volume I would size up by getting a KS60 instead of the extension collar, it weighs 14 g more but also 5 L more volume. The standard pack has a drawstring closure system rather than the dry bag type top which makes for easier access. By default, a 20 mm daisy chain is included on each shoulder strap up to the load lifters to hang external pockets or GPS device via a carabiner.

The 8 L front pocket is great for keeping snacks, a fleece, and knickknacks that you need on the go or alternatively storing a wet rain fly if need be with strong mesh judiciously sewn at the bottom for water to drain out. Complementing the front pocket is 1.8 meters of 2 mm elastic shock cord retained by 5 tie-out loops for attaching clothing and gear to the rear of the pack. An option here worth considering is the “custom front pocket form” where the top strap is anchored via a reinforcement patch to the pack rather than directly to the pocket. Takes stress off the front pocket and allows you to grab what you need without having to undo the top closure.

Completing the package are two 330D Cordura nylon side pockets with drainage holes at bottom the corners capable of snuggly fitting a 1-litre Nalgene bottle or a 2-litre bottle. As a custom request it’s possible to have them made taller however it means removing the pack to access the bottles, so I’d probably advise against that. Side shock cords on either side (3 mm x 80 cm) with line locks support taller items such as trekking poles or a tripod. I also opted for a 70D Black nylon ripstop internal pocket (20cm x 21cm) with mini-Velcro good for stashing keys and a trail wallet. However, I find the 1 cm x 3.5 cm Velcro tab a tad small and comes undone easily.

Frame and Carrying Comfort

The KS50 is available with a removable aluminium tube frame set to optimise load transfer on hips. For the 50 cm torso size the two external tubes are 52 cm in length with a weight penalty of 60 g. Having worn the pack with them removed the difference is noticeable so I’m happy I got them. While they don’t rub or cause any issues I feel from an aesthetical and weight point it would be better if the frame stays were carbon and routed internally. One minor issue I’ve found is the removable Polyethylene foam pad tends to push its way through the Velcro. Like what I wrote above regarding the internal pocket the issue could be remedied if it were ever so slightly thicker. I ended up trimming it by a centimetre or so to stop it from happening. Also, instead of using PE foam it would good if the removable pad were a breathable material such as C-Core like Yamatomichi offers as an option in their packs.

Overall, the anatomic padded hip belt with the frame stays and load lifters combined with the 10 mm foam padded shoulder straps makes for an amazingly comfortable pack. It’s worth adding that as the hip belt is sewn to the base of the pack tightening it doesn’t transfer the pack weight from the shoulders to the lower part of the body as much as more robust backpacks do. Having said that carrying considerably less weight means it’s not so much of a concern. Provided that you keep the total load to no more than 12 kg (26lb) you can happily carry it all day without issue.

Final Thoughts

The KS Ultralight KS50 backpack marks my first foray into the world of ultralight packs and from here on in can’t see myself returning to heftier offerings. As far as size goes, I can see the pack handling a week-long hike without a resupply stop however for a full weekend with winter gear I’d err towards the roomier KS60. Weight wise its shadow of my former pack and if you are willing to forego the anatomic hip belt and 3D spacer mesh you can shave off 100 g. Once more take your time perusing the various options to hopefully achieve an optimal balance between weight, cost, durability, and comfort.

To make the KS50 even better I recommend beefing up the mini-Velcro strips on the internal pocket and pad pocket closures, offering C-Core as an option for the removable pad and using 20 mm webbing for the top nylon handle for ease of handling on public transport. Lastly swapping the aluminium stays for carbon and integrating them inside the pack would complete the deal for me. Setting these minor nit-picks aside the KS Ultralight KS50 remains an excellent ultralight backpack ideal for any backpacker – from a seasoned thru-hiker, weekend warrior, to a newbie just starting out on their lightweight journey.


Lastly, Laurent was kind enough to throw in a minimalist climbing pack 125 g (4.4 oz) great for speed hiking / trail running or to bring along when base camping for light-footed mountain assaults.


Perennial favourite among the ultralight crowd for good reason; top-notch workmanship, comfortable to carry, is made of durable fabrics, and just at home on casual day hikes as it is on multi-day adventures.

   KS Ultralight KS50: Specs

Torso size: 50 cm (reviewer height 171 cm measured torso length 48 cm / 19 inch)
Weight: 630 g (22.22 oz) including customisations
Dimensions: Total length (collar fully opened) 80 cm x 28 cm x 20 cm
Volume: 48 L
Body fabric: Nylon 200D Spectra diamond ripstop
Default fabric: 330D Cordura nylon for the bottom, shoulder strap, padded waist and side pockets
Shoulder straps: 10 mm foam shoulder straps (12 mm X 65 mm width) inside lined with 2 mm of 3D mesh
Daisy chain: 20 mm included on shoulder strap up to the load lifters
Top closure: Drawstring with draw cord / cord lock
Side pockets: Two side pockets with drainage holes at bottom corners (fits a 2 litre bottle)
Side shock cords: Two shock cords (3 mm x 80 cm) with line locks to support taller items
Elastic shock cords: 1.8 meters of 2 mm elastic shock cord via 5 tie-out loops
Nylon handle: Top handle 13 mm nylon webbing
Country of origin: Japan


   KS Ultralight KS50: Customisations

+ Front pocket material X-Pac VX07 Blue with strong mesh at the bottom to drain water
+ Back with 3D spacer mesh
+ Internal pocket (20cm x 21cm) 70D Black nylon ripstop with mini-Velcro
+ Height adjustable removable 20 mm sternum strap with whistle
+ Internal pad pocket with removable 8 mm white Polyethylene foam pad fixed with mini-Velcro
+ Load lifter straps with 20 mm webbing
+ Anatomic padded hip belt with side load lifter straps (includes 38mm webbing and buckle option)
+ Removable aluminium tube frame set
+ Custom front pocket with fabric stripe at top X-Pac VX07 Black and separate top closure with triangle reinforcement patch
+ 20 mm strap webbing option in place of standard 13 mm (top closure and shoulder straps)

KS Ultralight KS50 Backpack:‎ ¥32,550 ($312 USD) (as at Dec 1, 2020)


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