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Reviews > Packs > Internal and External Framed Backpacks > Columbia Mobex Backpack > Test Report by Rick Dreher

Columbia Mobex Winter XL Backpack
Test Series by Rick Dreher



INITIAL REPORT - July 26, 2010
FIELD REPORT - October 04, 2010
LONG TERM REPORT - December 09, 2010


NAME: Rick Dreher
EMAIL: redbike64(at)hotmail(dot)com
AGE: 56
LOCATION: Northern California
HEIGHT: 6' 0" (2.10 m)
WEIGHT: 175 lb (79.40 kg)
FOOT SIZE US men's 11.5
TORSO LENGTH 19.5 in (50 cm)

I enjoy going high and light and frequently take shorter "fast- packing" trips. My longest trips are a week or so. I've lightened my pack load because I enjoy hiking more when toting less, I can go farther and over tougher terrain, and I have cranky ankles. I use trekking poles and generally hike solo or tandem. I've backpacked all over the U.S. West and now primarily hike California's Sierra Nevada. My favorite trips are alpine and include off-trail travel and sleeping in high places. When winter arrives, I head back for snowshoe outings in the white stuff.



Manufacturer: Columbia Sportswear
Web site:
MSRP: US$149
Year of manufacture: 2010


Weight (manufacturer): none given
Weight* (measured): 37.6 oz (1,066 g)
Total volume (manufacturer**): 2,013 ci (33 L)
Water reservoir volume: 3L
Recommended max. load: none given
Size & color: one size & one color only (unisex, black)
*Including supplied water reservoir
**As given for the standard Mobex XL

Key features: Single main compartment with perimeter zip opening and internal load divider panel; four zippered exterior pockets (one ea. top and bottom and two hip belt pockets); six interior pockets (one zippered); external "flex frame" with tool/pole anchor loops; padded backpanel, shoulder straps and hip belt wings; adjustable sternum strap with whistle buckle; 3 L internal water reservoir in pocket, with hose port; and "Omni-Heat thermal reflective hydration system."

Fabric: 20D nylon "Triple Rip" with Omni-Shield water repellant.

Full pack, displaying frame.



The Columbia Mobex Winter XL is a large, frame-suspension day pack with special features aimed at the wintertime adventurer. Its truly unique design element is an external flexible rod frame fitted to the front panel, not the back. It is a single compartment pack with a perimeter zipper opening that opens very wide because the zipper runs all the way to the bottom on both sides.

Inside the Mobex are several pockets: a water bladder pocket, a removable zippered mesh pocket, and four other open-top mesh pockets of varying size. A key internal feature is the mesh divider panel that helps separate and control gear, and keep it from falling out when the pack is open.

Back panel & straps.

Outside, the Winter XL (one of several Mobex models) has four two zippered pockets: two waist belt pockets, one top pocket and one bottom pocket. The external rod frame crisscrosses the back and anchors four tool/pole loops at exposed crossing points. The pack has no external bottle pockets, straps or strap anchors.


The Winter XL comes with a Hydrapak brand 3 L water reservoir with hose and valve.

Materials and Construction: The Mobex Winter XL is nicely made. The waterproof fabric is surprisingly thin--a weight reduction. The nylon mesh used in several interior pockets is likewise fairly lightweight and soft. The slender plastic frame rods are quite flexible and Columbia claims the pack can be crushed flat and they'll spring back into shape. We'll see. The back panel, shoulder straps and waist belt are all padded. Padding is covered with smooth fabric, not wicking mesh, and I can't tell whether the foam and fabric are breathable but hot weather use should reveal the answer. Buckles, toggles and related hardware all appear to be of good quality and are small for weight control. Exterior zippers (three in all) are not of the waterproof variety and the main zip is quite heavy-duty. All have easy-pull cord tabs.

Fabric edges, stitching and seams all look clean and even, with no loose threads, missed stitching or frayed edges. All exposed seams are bias-taped.


As noted, main compartment access is via perimeter zipper. The front panel swings wide from the bottom edge and because of the frame, retains its shape at all times. Most of the storage space resides in this front section, held in place by the stretchy mesh panel. Gear is accessed by unhooking the panel at two top anchor points. Three mesh ditty pockets are sewn into the back panel for stowing small items and a larger removable zippered pocket is anchored in front of the mesh divider.

Inside, front section on left.

Sewn to the back panel are the water bladder pocket and a short, wide, open-top storage pocket. Top center is the drinking hose exit port.

External Pockets: The hip belt pockets are large enough to hold snacks, sunscreen and small gear. The top pocket will hold similar items but the bottom pocket is a puzzle: while it covers the entire bottom panel it is absolutely flat and tight--basically a second fabric layer--so I'm not sure for what it's intended. Beef jerky?

Frame & Suspension: The Mobex frame is its truly unique feature, the likes of which I've never seen. Comprising a set of intersecting flexible plastic rods, the frame stretches the back panel into a domed lid resembling a tiny self-supporting tent. When zipped shut the frame's stiffness transfers to the back panel to support the entire pack. Columbia places toggled bungee cord tool loops at four points where frame rods cross, capitalizing on these strong points to take the load rather than sewing them to pack fabric. The loops are easily removed. Because of the full hip belt, the Mobex is designed to place much of the load on the hips rather than the shoulders. The sternum strap is vertically adjustable and fitted with a whistle buckle. Each shoulder strap has a d-ring and there are no load control straps.

Reservoir: The supplied water bladder (### brand) opens at the top, which should make it simple to clean and dry between uses. It closes with a sliding plastic clip, not a zip closure as with some of the competition. A drinking valve pops open and closed, so it's not technically a "bite" valve. The hose is fairly stiff clear plastic.

Winter Features: The Mobex Winter models use more of the waterproof pack fabric, have no external mesh or bottle pockets, and include a drinking hose enclosure to keep it from freezing. The hose routes inside the right-hand shoulder strap, accessed by a zipper. The enclosure is insulated and has reflective material and a pouch for holding a chemical hand-warmer pack.

Volume & Weight

Columbia hasn't posted volume and weight specs but presuming it's the same as the regular Mobex XL, the Winter XL should be 33 liters (2,013 ci). It weighs 37.7 ounces (1,066 g), which compares to 32 ounces (906 g) specified for the regular XL. The reservoir represents 4.4 oz (125 g) of this total. The Winter XL comes in one size only and is unisex (some Mobex models offer men's and women's sizing).


The Mobex Winter XL comes has several hang tags detailing select pack materials and design features, including the Exo Flex frame. There are no specs and few user instructions, but the Columbia Web site provides additional information. I doubt I would have figured out the tiny hand-warmer pocket without their documentation.

Mysterious bottom pocket, flounder cave?


The Mobex Winter XL is a big day pack (big enough that ultralighters ironically unconcerned with their backpack's weight could do overnights with it). It appears to offer plenty of capacity for cold weather day hikes with the usual bulky clothing, and easy access to that clothing. In addition, it should be possible to segregate wet items from the rest of the contents-a common problem in snow and rain. Two pounds (less than 1 kg) is reasonable for a full frame day pack in my experience, so the Winter XL's unique design doesn't incur a weight penalty.

With no sizing and no back length adjustment it will be interesting to see whether I can get a good fit. Big packs seem to attract big loads and among water, food, clothing, gear and camera stuff, I can probably have the Mobex weighing quite a lot. What's clear is the clamshell opening gives ready access to any amount of gear I may choose to carry.

Frame rods & gear anchor detail.


The Columbia Mobex Winter XL is an innovative and unique pack--unique primarily because of the frame. It's as large a day pack as I can imagine carrying, so I'm interested in how it handles various combinations of stuff (especially heavy camera gear) I might throw in it. Testing a winter pack in mid-summer will place an emphasis on its ability to manage heat and sweat. Since there's little external storage, I'm likewise interested in ease of main compartment access. I'll also be watching the wear points represented by the frame rod sleeves for damage. Finally, I'll work on a use for the peculiar bottom pocket.

Nits? The frame squeaks. This had better go away or I'm getting out the oil can.

Suggestions for Improvement? I'd prefer the standard Mobex waist belt bottle holster and exterior back pockets had been retained. If sticking snow is a consideration, the pockets could be made of something other than mesh that would better shed it.


Please check back in two months for the field report.

My sincere thanks to Columbia Sportswear and for the chance to test the Mobex Winter XL!


Field Locations and Conditions

Mobex packed.

I took the Mobex Winter XL on three day hikes in the northern Sierra (Desolation Wilderness and Tahoe basin) and some local excursions closer to home, in the flatlands. Weather was always sunny with temperatures ranging from hot to merely warm: 95 F (35 C) to 70 F (21 C). Elevations ranged from sea level to 9,200 feet (2,800 m) and my longest day's mileage was about eight (13 km). Terrain has been flat and smooth to steep and rubble-strewn, including a bit of cross-country. I also tried adapting the Mobex to my work commute, as proposed in my application. More on that, below.

Field Performance

Loads and Loading:The Winter XL is a big day pack with a lot more space than I typically need in mild conditions. For me, ample space attracts stuff to fill it, "Hey, why not toss in an extra jacket or a bivy sack, just on case?" After some experimentation I generally follow a loading pattern. Most of the gear space is in the "clam shell" pack lid, behind the divider panel. I load this first, beginning with spare clothing in a stuffsack. Atop the clothing go food and camera gear. Attaching the panel then anchors this gear in place. The mesh pockets at the back of the lid hold small items, extra snacks and the like. Into the removable mesh pocket at the lid's bottom go cellphone, headlamp, knife and first aid kit.

Removable mesh pocket holds gadgets.

The back panel holds the water reservoir (when carried) in its sleeve. The wide lower pocket can hold other items, such as toiletries. A folded flat map can go either into the unoccupied hydration sleeve or, if I'm carrying the reservoir, rolled and shoved into the low pocket. Once I get this far I zip the pack halfway closed, although sometimes the bottom of the two halves are overpacked and I have to shift items for it to close. Before completely closing it, I'll add a water bottle or two (if not using the reservoir) and a wind jacket or clothing I might want on rest stops.

A typical Mobex load.

The top outside pocket works great for my GPS and another small item or two, and the roomy waist belt pockets hold snacks, sunscreen, lip balm, compass and sundry items. These are the only two pockets accessible on the go.

A drinking hose is routed through a port behind the haul loop and into the right shoulder strap's enclosed hose pocket. The angled nozzle pokes out the pocket's bottom, below the zipper. Hiking poles strap quickly and securely on back using the toggle-and-elastic anchors, conveniently placed where frame rods cross.

While I've assembled test loads as heavy as 20 pounds (9 kg), my actual trail loads have been less, with a top of about 15 pounds (6.8 kg), other times less than that.

As to the pocket at the pack's very bottom, I offer the following.

Dark as winter clouds
I am confounded by you
Mystery pocket

I did find a wilderness permit stows there, for what that's worth.

Oh pocket, pocket, wherefore art thou, pocket?


The Mobex XL fits me quite well. The waist belt wraps comfortably and amply supports a good portion of the load (not all day packs allow load transfer to the hips). The buckle is attached to the left hip belt wing where it doesn't dig into the mid-gut or interfere with a belt buckle. The webbing waist strap is incredibly long and needs a major trimming, which I'll do next time the household sewing machine is out (to fold and sew the strap end).

The shoulder straps are likewise comfortable and the sternum strap has plenty of up and down travel adjustment. Properly adjusted, the pack is very comfortable because it both controls the load well and isolates my back from the contents. The back pad foam is quite dense, providing support and protection.

On the Go: As noted, the Mobex gives good support and fits me well. On the trail the load is well controlled, so the quirky external frame seems to be doing a good job. A huge relief is that the frame doesn't squeak while I'm hiking, because it still does when I intentionally flex it. I can't find anything to fault in either the pack's fit or its load control, it handles very nicely.

The downside of the Winter XL is it's not designed for heat. The back panel doesn't breathe or wick away sweat, and it's noticeably hot on hot days-my shirt and lower back get soaking wet in no time. In addition, the black fabric absorbs heat from sunlight and melts certain snacks and generally heats the gear and supplies. The crafty hose cozy is fussy to open and close whenever I want a drink, and water in the hose itself gets hot. As long as I've added enough ice, the water supply stays cold for a decent length of time, as it's insulated pretty well from my back by the pack's padding.

Access to Contents: As noted, I can only reach the drinking hose and two front pockets while hiking, everything else requires taking the pack off. Presuming dry, clear ground to lay it on, the pack opens wide for excellent access to the contents. Some digging is required to get at items at the bottom of the back panel, but the divider panel releases easily to get out of the way. Lacking a space to open the pack wide, it's a challenge to dig out items buried deep.

Back panel with reservoir and stowed gear.

Water Reservoir and Drink Hose: The 3 L Hydrapak brand water reservoir is easy to fill, stow, clean and dry. The sliding clip lock gives good access and the bag can suspend from a hook-and-loop strap inside the pack. The large-diameter hose gives good flow and the 90-degree angled bite valve has a push/pull shutoff. The hose can be stiff (when cold) and has developed some creases where it has kinked. Nevertheless, flow still seems okay. Valve shutoff action is stiff and I sometimes have difficulty opening and closing it fully. It occasionally drips water if not closed completely. Water that accumulates in the hose can taste "plasticy" but the reservoir itself seems to impart no taste. I can also remove the valve from the hose and pump filtered water directly into the bag without removing it from the pack. Nice.

Hose cozy, also solar cooker.

Commuting: I'd proposed using the Mobex for my commuter backpack, but the change to the Winter XL model presented me with a backpack much larger than what I use daily. My work stuff fills the XL perhaps halfway, and it seems very large for cycling. On public transportation its clever frame keeps it full size and too large to easily stow at my feet. It's just not a match for the task.

Wear and Tear: There has been no observable damage or wear to the Mobex.


The Columbia Mobex Winter XL is a big, comfortable day pack that holds a lot of gear and supplies. The peculiar exoskeleton frame does a good job controlling the load and helps maximize pack space, while seeming to be strong and light. Panel-loading gives good access, both for packing and accessing gear.

This isn't a pack I find comfortable in hot weather because it emphasizes protection from cold and precipitation over ventilation and wicking. But since it has Winter in the name, that's not a big surprise. Fall has arrived, so I hope to yet test the Winter XL in its intended environment. I also note that since the initial report Columbia has issued the Winter XL in two new color schemes, which will both make the pack more visible and collect less heat from the sun than all black.


I think Columbia should reconsider their deletion of exterior side pockets on their winter models. I'd like them there to keep water, sports drink and other items of convenience within hand's reach.


My sincere thanks to Columbia Sportswear and for the chance to test the Mobex Winter XL.

Please check back in two months for the long-term report.


Long-Term Test Locations & Conditions

I took the Mobex Winter XL on four day hikes in the Tahoe-region Sierra Nevada. Two trips were in clear weather, one was rainy and on the last hike I finally used the Mobex in snow. Temperature ranged from mild to cold (60 F the mid-20s F or 16 to -4 C). Elevations ranged from 6,000 to 8,500 feet (1,830-2,600 m) and my longest hike was 10 miles (16 km). Terrain was hilly and the trails varied from smooth and easy to rocky and rough. The snow was fresh and loose, except when following packed trails.

Field Performance

Loads and Loading: Packing winter clothing at last, I filled the pack more than before, capitalizing on the Mobex XL's capacity. The benefits of having much of the storage in the front section becomes more obvious with a full pack when placing the water reservoir in its pocket. This system is much easier than stuffing a full reservoir in behind a lot of other gear (a process I dislike in typical pack designs).

The internal pockets offer plentiful small-gear stowage, but I find myself mostly using the large one at the base of the backpanel and the detachable mesh bag. When I remember the other pockets are there, I'll stow snacks or other small items in them. The top outside pocket is very handy for my first aid kit, GPS and headlamp, and the waist belt pockets are home to sunscreen, lip balm and snacks, as before.

I continue using the gear loops to attach my trekking poles--this is a very handy design. I can't figure out a way to attach snowshoes, which seems unfortunate on a winter daypack. On my snow trip I needed the snowshoes the whole time, so carrying them wasn't an issue.

Only on my last trip did the shoulder strap drinking hose cozy seem worth the bother. I didn't place a chemical warmer inside but the hose did not freeze in the subfreezing weather (I don't know at what temperature this truly becomes an issue).

Weight, Comfort, Fit: With a top trail weight of about 15 pounds (6.8 kg) the Mobex controls the load nicely. As noted in the field report, the Mobex XL fit is comfortable and my heat and moisture management issues disappeared as the thermometer dropped. I cut off surplus hunks of the very long waist belt webbing, leaving less to flap about. When adjusted the pack doesn't shift or sway and nothing stowed inside digs into my back. The exoskeleton frame creaks from time to time, perhaps reminding me it's busy controlling the pack load.

Weather: Water leaked into the pack on my rainy trip. It seems to wick in through the zippers and perhaps through the stitching as well. I didn't take on buckets of water but will need to either pack critical contents in waterproof sacks or wear a poncho over the pack in the future. Snow collects on top and along the frame sleeves, but I didn't notice any significant meltwater inside.

Access to Contents: The only new observation I have is the need to place the pack on the snow or wet ground to get at the contents, as with other panel-loading packs I've used. I'm grateful for the stretch panel that keeps the contents in the pack's lid from spilling on the ground. It does a good job keeping the load in place.

Water Reservoir and Drink Hose: The reservoir worked well the rest of this test, with no leaks noted. I continue to like the wide-open top design that helps dry it out between trips. The hose still makes water that collects in it taste a little like plastic.

Wear and Tear: the test Mobex Winter XL remains in good shape. The thin fabric has held up, the frame and frame sleeves are fine and the zippers and hardware are likewise in good shape. I have not "bashed" this pack on brushy cross-country routes, so cannot comment on the fabric's resistance to sharp branches or rock surfaces.


As in the field report, I continue to find the Mobex Winter XL is a big, comfortable day pack with good load control and lots of space while being reasonably lightweight. Comfort goes up as temperatures drop, as implied by the winter model's design differences from the regular Mobex models, and some of the winter-specific features become meaningful (such as the drinking hose routing).

Suggestions:" To repeat the field report I'd like exterior side pockets, which would make more gear available without opening the main compartment or even setting the pack down. I'd also like a way to attach and carry snowshoes, at least lightweight snowshoes, and waterproof zippers would enhance weather-resistance compared to the current zips.

Continued Use

This test's timing barely got me into winter so I'll continue to use it the rest of this season. I'm satisfied the Columbia Mobex Winter XL offers some unique capabilities for winter travel, such as ample capacity for bulky clothes and the drinking hose insulation. It's certainly comfortable and it controls my gear well. It's a seasonal specialty pack and as such, I'm unlikely to give it any further summertime use.


My sincere thanks to Columbia Sportswear and for the chance to test the Mobex Winter XL.

This report was created with the Report Writer Version 1.5 Copyright 2010. All rights reserved.

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