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Crux AK47 and Crux AK57 Packs (UK)

Mini-review for the 2010 State of the Market Report on Internal Frame Backpacks.

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by Roger Caffin | 2010-09-28 00:00:00-06

These two packs were designed by Carol McDermott, a New Zealand climber now in Europe, and must be seen as alpine climbing packs for Europe, not as mainstream American walking packs. This has greatly influenced their design: they are made of some extremely tough fabric and are almost entirely lacking in all the frills normally found on American packs. Why? Because they have to take being hauled up cliff faces on the end of a rope. The weather in Europe (and especially the UK) is never as reliable as in America either - unless you count a very high probability of wet weather as being 'reliable.' So in addition to being made of tough waterproof fabric, the majority of the seams and fittings on the back of the packs are welded and sometimes taped, not sewn.

The harness consists of an 8.0-mm diameter 7001-T6 aluminium alloy U-shaped rod, the same as is used on the Lightwave packs (Lightwave is a sister company), plus a very firm foam back. The hip belt is simple, with 50-mm (2-in) webbing and buckles. Even the draw cords on the light waterproof nylon throat are climbing-oriented: they are 4-mm Rivory-Joanny accessory cord and can be used in an emergency as abseil slings. Despite all this strength - or perhaps because of it - Crux do not quote a recommended load for these packs. I guess if a climber can get the gear in, he'll carry it?

The clean exterior means no mesh pockets on the sides or the back and no bulging back pocket. The outer surface is essentially a smooth tube of almost indestructible Kevlar/Cordura fabric, the lid is of the same fabric, and the base is a double layer. Anchor points are reinforced with bonded patches (for sliding over the rock). The insides of the attachment points are all waterproofed. There are 'side pockets,' but they are low-cut and designed to take tent poles and glacier wands. They are not big enough to actually hold gear. The website claims the side pockets are 'stretch,' but the only stretch is the elastic binding along the top edges. They do have grommetted drain holes. The throat is light, waterproof nylon, but is hidden under the lid and not exposed. I know some American packs boast about their strong fabric, but this combination is in a class of its own.

Internally the frame consists an 8.0-mm diameter 7001-T6 aluminium alloy U-shaped rod frame. It looks like Easton tent pole material, but lacks the brand and is a bit more bendable. Getting it out is a bit of a wrestle, but quite doable. You don't need to get it out to alter the tilt at the base though. The back has a good slab of Lycra-covered moulded foam, but no sheet of hard plastic. The lack of a plastic sheet does not seem to be a problem, however: the foam is quite solid. The shoulder straps are not wide, but seem quite adequate with well-padded edges. The hip belt has wiggles in it to try to conform to waist lines and is only 70 mm (2.75 in) wide. The webbing and buckle are 50 mm (2 in) wide.

There is a bladder sleeve inside the main bag. The lid has fully-taped seams and a pocket with a solid waterproof zip - but then, it does rain in the UK. There is a key hook inside the pocket and a not-hugely-obvious zipped security pocket on the underside of the lid. The lid is removable and can be raised up above the nylon throat on its straps should you wish to tuck a tent or a rope under it. There are two ice axe attachments on the back of each pack.

The measured values for weight and volume for both the AK47 and the AK57 came out very close to specification - close enough to make no difference.

These are not packs for the casual walker of easy trails: they just wouldn't make sense. But for anyone looking for a serious alpine pack, or a pack for some very serious arguments with sabre-toothed jungle, these are very good. You might need to pay more attention to picking the appropriate torso length than you would otherwise expect, of course, and it would be best to try one on and check the length before you buy. We have included them in this survey because they meet the selection criteria, and it is always interesting to see the opposite end of the spectrum from the silnylon creations.

Crux AK47 Pack

Pack Rating Qualifications
AK47 Above average Very rugged alpine pack

We found this pack to be very small in torso length, which caused us a bit of a problem until we understood what was going on, and our trouble was compounded by the selection of a Size 1 version - essentially a Small. The torso length is short compared to most other packs because it is designed to have the hip belt up around your waist, leaving room for a full climbing harness around your hips below the pack. Once you adapt to this, it all makes sense. However, a size #1 is probably a bit small for most people, except for serious climbing.

Crux AK47 and Crux AK57 Packs (UK) - 1
Crux AK47, 1.17 kg (2.58 lb), 45 L (2800 cuin), #1, #2, #3

The hip belt seemed quite adequate - except that it did not really sit down on Sue's waist very well, and was marginal on mine. The attachment points for the load lifters seemed a bit close to the pack as well. Both of these problems are entirely due to the size of the pack, as described above. When used as a climbing pack (ie with a harness below the pack) it started to work much better, although I would still prefer a size #2 if I needed to carry a lot of gear. However, it may be noted that I was able to get the full load of Test Gear into the pack, despite the apparently small size.

Both packs include two ice axe attachments. The top straps for these are partially covered by the lid straps when not in use, but I don't think this matters in practice. What is nice is that the bottom loops are well clear of the bottom of the pack, so the ice axe head does not dig holes in a wooden floor when you put the pack down.

Crux AK57 Pack

Pack Rating Qualifications
AK57 Above average Very rugged alpine pack

This is the big brother to the AK47 - and we tested a size #2 rather than a size #1 just to be sure. With the larger size, the torso length was fine, and the hip belt sat on my hips and Sue's hips rather better. The load lifters also worked much better. Quite definitely all this was a result of getting the right torso length. The bag swallowed the Test Gear quite easily too, even though the measured volume was not that great. I think the shape of the bag was better able to handle the lumps. There was nothing put in the lid pocket, although there is quite a bit of room available there - about 3 litres, in fact.

Crux AK47 and Crux AK57 Packs (UK) - 2
Crux AK57, 1.30 kg (2.87 lb), 52 (3200 cuin), #2, #3

This larger unit has an extra feature over the AK47. There are what look like extremely tough 'panic handles' at the bottom on each side. You can see them in the right hand photo, especially the one on the right hand side of the pack. No, they are not really for panic :-), they are for holding skis. You drop the ski into this loop and use the top of the compression strap on the side of the pack to hold the top end of the ski. This is easy to do because the top end of the strap is attached with a side-release buckle (just visible in the other two photos). The loops are tough because skis do often have metal bits and edges which can rub, although I doubt skis could do much damage to this pack fabric. The loops are not shown in the company photo at the left: I suspect they may be a recent addition to the design.

The middle photos for both packs show the haulage loop. This is wide - wide enough that one person holding the pack can easily pass it up to a second person to grab. Function drives design.

This is a mini-review in the 2010 Lightweight Internal Frame Pack State of the Market Report. The articles in this series are as follows (mini-reviews can be found in Part 2), and a subscription to our site is needed to read them.

  • Part 1A covers the very basics and lists all the packs in the survey.
  • Part 1B covers the frame and harness which carry the pack itself.
  • Part 1C covers the main bag and all the other pockets, plus the all-important question of comfort.
  • Part 2 in this series covers the individual packs tested.


"Crux AK47 and Crux AK57 Packs (UK)," by Roger Caffin. (ISSN 1537-0364)., 2010-09-28 00:00:00-06.


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Lightweight Internal Frame Packs: a State of the Market Report - Part 2: The Packs
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Coin Page
(Page0018) - MLife

Locale: Southeastern USA
External Frame Packs? on 10/18/2010 20:47:02 MDT Print View

Thanks for a nice review Roger.

Perhaps outside the scope of this review, but since the subject of external frame packs has come up: do you have any recommendations for lightweight, commercially available, external frame packs that capture your "H - frame" idea?

Back in the old days, my external frame pack and hip belt could shift almost all the weight onto my iliac crests, or alternatively, onto the greater trochanters.

I find now, with increasing age, a decreased tolerance for prolonged heavy loading of the L5-S1 disk, and the SI joints. Anything much over 20 lbs all day, no matter how it's distributed over the shoulders or the lumbar area, starts to hurt.

Some of the individual pack reviews and comments above suggest some of these packs come close, but it sounds like you think the external frame is better at overall comfort - issues of durability, fragility and standing up to heavy brush aside.

Am I on the right track here? Any advice. How can I get most of the load back on the sides of my hips - the iliac crests - and still go lightweight?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: External Frame Packs? on 10/20/2010 23:43:42 MDT Print View

Hi Coin

Sorry, but I don't have a simple answer for you. I think I noted somewhere in the review that my hips are rather narrow, such that many hip belts do not work very well on me. For this reason I have always preferred to carry the load on my back. This does *not* mean 'on my shoulders'.

With my design I find the load does go through the mesh on the back of the pack to the full area of my back. Frankly, I am not really sure why this works so well, but it does work for me.

I am sure that it won't work for many other people, and that a solid hip belt will work better for them. In this sense, fitting a pack to a person is very much like fitting a pair of shoes. I sigh (for the same reason) when I see someone ask 'what shoes should I buy' and then read a reply that they should buy SuperDucksMultiWeb shoes.

However ... I will offer the following advice - which is also in the Review somewhere. Try to buy a pack which matches your torso length, but do not buy a pack with a torso length which is too short. Better to have a pack torso length slightly longer than your torso length: that will throw the load onto your hips more effectively.

Even better: pick a pack in the right size with an adjustable torso length. Then fine tune over several trips how it fits you. Yes, I definitely give brownie points to packs with an adjustable torso length.

I also give brownie points to packs with a solid stiff harness or frame. Frameless packs are all very well if my total load is under 6 -8 kg. Over that the weight of the harness is far outweighed by the added comfort it brings. Now, I know this comment will attract numerous responses contradicting me and saying how wonderful a frameless pack is. Well, as with shoes ...

Can an external frame pack (like mine) stand up the 'heavy brush'? Chuckle. Trust me, the scrub in the Australian Blue Mountains (and in SW Tasmania) is definitely world class.

A commercial equivalent? Sorry - at this stage I cannot make a recommendation, because I don't know.


Cameron Semple
(camS) - F

Locale: Brisbane, Australia
Shadow on 10/21/2010 06:43:52 MDT Print View

I had a look at a Shadow this evening at a local distributor. I liked the clean, no frills look. Didn't have time to load it up though. You mentioned the thick webbing used on the hip belt. I found it virtually impossible to tighten the belt once fitted. The webbing was so rough that it wouldn't pull through easily. Combined with the older style of pulling the straps out rather than into the middle.

Any ideas when the 2011 line of packs will be available? The Umbra looks interesting.

Edited by camS on 10/21/2010 06:45:49 MDT.

al b
(ahbradley) - M
small manufacturers / osprey atmos on 10/21/2010 15:46:43 MDT Print View

Roger (Caffin):
Would any of the ultralight small manufacturers be interested in making your external frame sacks.

The osprey atmos 50/65 has a kind of all back mesh (for ventilation) but I think the gap between back and pack is bigger. I didnt like the shooulder straps.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: small manufacturers / osprey atmos on 10/21/2010 20:58:46 MDT Print View

> Would any of the ultralight small manufacturers be interested in
> making your external frame sacks.

I would be delighted if someone did want to.


al b
(ahbradley) - M
osprey exos possible equiv to Roger (Caffins) MYOG external frame on 10/22/2010 04:55:27 MDT Print View

Roger (Caffin):

Actually, from reviews, the osprey exos 46/58 looks better than the atmos, as still has kind of all back mesh (for ventilation) but the gap between back and pack seems smaller, and the rucsac storage looks less curved.

Perhaps you could borrow one and compare it (not using waist belt) against your external frame pack.

Coin Page
(Page0018) - MLife

Locale: Southeastern USA
External Frame Packs? on 10/24/2010 09:12:13 MDT Print View

Thanks Roger.

Yes, like finding well fitting shoes. But I did find those (wider), so I keep my optimism for finding the perfect pack for heavier loads. Thanks for the reminder/emphasis on torso length (longer for me).

The Aarn packs, and LuxerLite pack seem hopeful. Discussions of these packs over the last 5 years give lots of opinions both ways. I would love to hear from owners/users of these packs what they still think of them now.

Any other packs in this general class - lightweight with enough frame to transfer all the weight to my hips if I want to - that anyone thinks I should also consider? Any packs in the review above come close for a long torso?


Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: osprey exos possible equiv to Roger (Caffins) MYOG external frame on 10/24/2010 15:35:08 MDT Print View

Hi Alan

The survey covered both the Exos 46 and the Exos 58. Nice packs.


Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: External Frame Packs? on 10/24/2010 15:38:09 MDT Print View

Hi Coin

The survey lists the available pack sizes. I was testing Medium in just about everything, but many of them have a Large model available.

Which one to choose? Ahhh... Very personal. 'Every body is subtly different ...' as they say on the planes.


Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: External Frame Packs? on 10/25/2010 12:46:16 MDT Print View

"The Aarn packs, and LuxerLite pack seem hopeful. Discussions of these packs over the last 5 years give lots of opinions both ways. I would love to hear from owners/users of these packs what they still think of them now."

I have used both of these, and in both cases they are nice packs, but I ended up using them without the front pockets. They just didn't work for me. however, if you like front pockets, I find the LuxuryLite pocket (and frame) to be more functional and cooler. I also ditched the LuxuryLite cylinders and modifies a GoLite Gust to attach to the frame. Excellent volume and comfortable carrying. Note: the LuxuryLite pocket restricts you vision more than the Aarn. Also note, I have both of these for sale. If you are interested, shoot me a PM and we can negotiate a price.

eric chan
(bearbreeder) - F
frogs ... on 10/26/2010 06:24:59 MDT Print View

just a note for others that the french site i-trekkings has done a similar test with packs in roughly the same weight and volume range

note how the Decathlon Forclaz 50 Ultralight scored very high in comfort and on score/price while being the cheapest and lightest pack

just shows you what can be done ..

just use google translater on the links below

Edited by bearbreeder on 10/26/2010 06:28:48 MDT.

al b
(ahbradley) - M
exos 58 usage with no load thru hip belt on 10/27/2010 15:08:48 MDT Print View

Roger (Caffin):

I checked the articles 1A-C,2 butt did not find a mention of testing the exos 58 with no load bearing via the hip belt i.e. a comparison against the way your your external frame myog pack is used.

Do you still have one for a hip-beltless comparison against your external frame pack.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: exos 58 usage with no load thru hip belt on 12/16/2010 20:22:34 MST Print View

Hi Alan

Sorry, this dropped off the radar for a while.
Unfortunately no: the Exos packs were farmed out to Australian readers.


Eric Botshon
(Ebotshon) - F
Exos 46 on 07/12/2011 10:36:03 MDT Print View

The review mentioned that the osprey pack was closer to 40 than 46 liters.

Any chance this test was done with a size small pack instead of the medium? The smal torso length pack is smaller than the stated 46.

Willem knopper
(willem65) - MLife
Exos Frame on 09/08/2011 15:41:10 MDT Print View

I have tried the Exos and I find them to be to very ridged, the pack does not move with you (back) at all. I personally think they are really just a fancy external frame pack. I did like the idea of the air flow but was just very disappointed how it restricted your movement especially if you were to use it doing any walking other than on the flat.


Phillip Damiano

Locale: Australia
Jansport Big Bear on 03/22/2012 21:42:44 MDT Print View

Roger mentioned in one of his comments here:
(Yes, we kept a few, for specific functions. The rest have been passed on to Australian & NZ BPL members (kept the postage down) for further field testing. I expect that they will provide some Reader Reviews in due course).

I'm one of those Australian BPL member, I've recently acquired one of the Jansport Big Bear 63 prototype packs of Roger.
The pack has only been in my possession for a few weeks now, tested on day hikes including some rock climbing.
The Harness is very comfortable and the material is very durable. I've tested this on a Off-track hike recently with very thick vegetation. I got scratches over me, the pack survived with no scratches.

I'm yet to test it out as a Overnight hike, but I can't see it causing any problems there. It's a nice pack. I do like the colour that the prototype pack was supplied in with the orange trims.

This is an on going review, I will keep you's updated on my findings on my next overnight hike, which is not for another 3 weeks from today. In a couple days, I've got a day hike I'm planning on, I will pack all my overnight hiking gear into the pack for a test to see how the pack feels with some weight in it. My base weight is just under the 8Kg. I'll add a few litres of water to that, making a total weight of 11kg.

So far, I like the pack. It's not exactly on the ultra light weight at just under 1.5kg but it does have a good frame and harness.Jansport Big Bear Prototype Pack

Edited by Phillipsart on 03/22/2012 21:51:42 MDT.

Phillip Damiano

Locale: Australia
Re: Jansport Big Bear on 03/24/2012 19:33:34 MDT Print View

Packed my hiking gear into the Jansport Big Bear pack yesterday and went for a walk around the block with apx 12kg load. Pack is comfortable, enough room for 5 or 6 days of food. No complaints.

Will be continuing wearing the pack with my gear on daily hikes for the next couple of weeks as training for an upcoming 3 day overnight hike in some steep terrain.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
"Pocket Man" on 06/14/2012 21:41:39 MDT Print View

I own an older - and IMHO better - version of the REI Flash 60. It's the REI Cruise UL 60 (2nd model). That pack absolutely NEEDED side pockets. Fortunately REI had "aftermarket" pockets at that time, but no longer.

I like side pockets because they store stuff I may need quickly like 1st aid kit, water treatment kit, toilet kit, potty kit, and things I don't want inside my pack
Like stove stuff including fuel. (For ex., ESBIT tabs smell fishy -like two other things I know of. ;O)

My REI pockets add 400 cu. in. each and make the pack "complete" in my dinosaur mind. Yeah, I'm a geezer and like exterior pockets. As another poster said of the Ospey EXOS that front "shovel" pocket is nice and can hold that wet tent, etc. Same goes for my Cruise UL 60 - which should really be called the "UL 50" - sorta like many post-recession 401-K funds should really be called "201-K" funds.

SPIRIDON Papapetroy
(spotlight) - F
Osprey Exos on 09/09/2012 21:15:47 MDT Print View

Has anyone had pain in the part of the body where the lower part of the frame touches it. I am a bit worried because it doesn't have any padding.

Phil Cawley
(Philc) - M
Lightweight Internal Frame Packs. on 04/08/2015 21:50:37 MDT Print View

Hi, First time I've ever made comment. In my mind (without a doubt!) everything considered Aarn Packs are the way to go! I've got four of them (one for nigh on every occasion!) and would NEVER consider going back to the old style! Try 'em and you'll use 'em. Phil.