Crux AK37 Pack Review

The Crux AK37 is marketed as an Alpine sack - and that of course makes it well suited to Scottish winter and UK multi pitch rock too. It is made from extremely durable material (40% Kevlar and 60% Cordura - the previous generation of AK sacks had only 28% Kevlar) and has welded seams: in fact, it looks and feels pretty much indestructible. The capacity of 37 litres is a useful size for mountain routes in all seasons, and the sack weighs just 1040g - lighter than its sturdy appearance might suggest.

A bombproof pack that can take pretty much anything you want to throw at it...  © Helen Rennard
A bombproof pack that can take pretty much anything you want to throw at it...
© Helen Rennard

The main features are: an external lid pocket with welded seams for water-resistance; a roll-top closure for a completely waterproof main compartment; an oversized haul loop that's easy to grab and clip; top and (removable) side compression straps; a 40mm webbing waistbelt with low-profile full-sized hip-fins; axe holders and stretchy wand pockets.

Testing

Though I've not yet had an opportunity to test the AK37 for Alpine climbing, I used it on all of my Scottish winter climbing days over the recent season - an environment that's similarly testing to the Alps.

Pros:

  • Comfortable
  • About as waterproof as a rucksack can be
  • Very tough material
  • Light
  • Large grab handle
  • Simple design

I have found the sack to be comfy for load carrying. I am 5'6" and have the Regular back size; the fixed back length is fine on me, and the hip belt belt sits in the right position. There is adequate padding on both the belt and shoulder straps for comfort when the pack is fully loaded with heavy climbing gear.

I could imagine this rucksack lasting for decades as the material is extremely tough and the welded seams mean that there is no stitching to fray. Other rucksacks I have used in the past have ended up covered with multiple repairs towards the end of their lives, particularly on the shoulder straps. I would be surprised if I ever need to repair the AK37!

The rolltop closure is glove friendly...  © Iain Small
The rolltop closure is glove friendly...
© Iain Small

...and helps keep the weather out  © Iain Small
...and helps keep the weather out
© Iain Small
.

Features wise, this is a case of less is more and simple functionality trumping anything flash or unnecessary. The large grab handle makes it easier to pick the rucksack up when wearing gloves or mitts, and to clip it to belays. There are two ice axe holders on the rucksack but my preference is to store my axes on the sides of the rucksack. The side compression straps keep the axes firmly in place; and they're also strippable if you want to simplify the pack further.

Given its mega-tough construction this has to be considered a light rucksack, and it also has the big advantage of remaining light in wet conditions as it is made from non-porous materials. Previous packs I have used have become wet and heavy after a day out in rain or wet snow. The Crux AK37's waterproof material and roll-top closure system (the same as that on a dry bag) means that a waterproof rucksack liner isn't necessary when using this rucksack.

photo
The 37 litre capacity is just big enough for Scottish winter
© Helen Rennard

photo
Large grab handle and waterproof top zip
© Helen Rennard

Size-wise, I think this rucksack is just big enough for a day Scottish winter climbing. If I am climbing in a pair I am not able to fit a rope inside the rucksack and will instead need to have it strapped under the lid. If climbing as a three and sharing the gear the rope will fit into the rucksack. Saying that, I tend to walk in wearing not that much clothing and then put on a lot of layers at the bottom of the climb. People who wear more and carry less clothing will have more room in the rucksack for their rope!

Cons:

  • No internal pocket for keys
  • Top lid not adjustable
  • Top compression strap (for items under the top lid) very long
  • Side compression straps quite short, especially in relation to the length of the top compression strap

The lack of an internal pocket or any means of attaching keys is a problem if you normally keep your keys in your rucksack. There is a risk of keys falling out of the top pocket if they are not somehow attached and you are getting gloves, food etc out. This is such a small, simple thing to add, but one that makes such a difference in use, that you'd think every manufacturer would include a key clip as standard. Not everyone likes to carry keys in their pack, but it would be nice to have the option!

The lid sits high and can restrict head movement when looking up  © Helen Rennard
The lid sits high and can restrict head movement when looking up
© Helen Rennard

Another downside is that the top lid cannot be adjusted or removed. If the sack is full, and in particular if you have a rope or other item strapped under it, then the lid can end up sitting at a position that limits backwards movement of your head. I have found this irritating when looking upwards - i.e. when walking uphill and looking up towards the crag - as the position of the top pocket prevents me from tilting my head back as far as I would like. When climbing with the rucksack on I've found my helmet being pushed forward by the top of the rucksack every time I look up. The rucksack has not been full at this point, and the top pocket only contained a pair of mitts and a headtorch. This is not ideal if you're intending to climb with the pack on - something you're bound to do in the Alps even if you tend to prefer leaving packs at the bottom of Scottish winter routes. Being able to remove the lid, or drop its position down the front of the pack a little, would have been helpful.

The top compression strap is very long, to the extent that there is a lot of it left even after strapping a rope under the top pocket. However, the side compression/storage straps seem unusually short by comparison, and are at odds with the top compression strap, i.e. if the full length of the latter was used, the main straps would be too short to reach their clips. The sack would have benefited from having longer side straps.

Expecting tough weather? the AK37 is built to take it!  © Helen Rennard
Expecting tough weather? the AK37 is built to take it!
© Helen Rennard

Verdict

It's not a budget option by any stretch of the imagination, but the Crux AK37 is an exceptionally hard wearing rucksack that should offer many years of reliable service. It is excellent for using in wet conditions and harsh weather as it is made from material that is more or less bombproof, and also very resistant to soaking up water. With a simple no-frills design that will appeal to alpine and winter climbers, and even Scottish winter munroists, the sack is easy to use when wearing mitts or big gloves. Some details (such as strap length and having an adjustable lid) could be better, but overall the Crux AK37 works very well as rucksack for Scottish winter climbing, and would be equally at home in the Alps.

Crux say:

The AK37 ushered in the third generation of crux's AK backpacks, being the first to come off the production line in the relaunch of our iconic range. What's new is a lighter body fabric with a 40% Kevlar® / 60% Cordura® composition (compared with 28% Kevlar on the previous generation) and a fully welded construction. A top-loading style, it now features a roll-top closing system under the hood for complete waterproofness. The classic, minimalist design and clean lines remain unchanged.

The baby of the range, the AK37 is frequently used by owners of one of the larger AKmodels as a companion for all their non-mountaineering activities, such as cragging, multi-pitch rock, back-country skiing, canyon hiking, or any other abusive activities that normal daypacks won't handle.

  • Price: £229
  • Weight: 1040g
  • Capacity: 37 litres
  • Fabric: 40% Kevlar / 60 % Cordura, 240 g/m²
  • Frame: 2 x 7mm Ø tubular titanium stays (removable)
  • Sizes: Regular and Long
  • External lid pocket with welded seams for water-resistance
  • Roll-top closure system for a completely waterproof main compartment
  • Oversized back haul loop – easy to grab and clip
  • Top compression strap
  • Side compression straps – quick and easy to fit or remove
  • 40 mm webbing waistbelt with low-profile full-sized hip-fins
  • Two ice-axe holders
  • Stretch wand pockets
  • Welded construction throughout

For more info see crux.uk.com

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22 May, 2018

I've got a 10 year old AK37 and it has completely fallen apart. Big holes in the base, one of the plastic clips has broken, and one of the internal metal poles broke through the lid of the sack after about a year. Still usable, but build quality? Hmmm.

24 May, 2018

Not having a small stash pocket under the lid with a clip for your keys seems like a major oversight to me. Always handy to have that pouch for small items that live in your bag all the time. £225 seems very expensive! 

24 May, 2018

"...climbing with the rucksack on I've found my helmet being pushed forward by the top of the rucksack every time I look up. The rucksack has not been full at this point, and the top pocket only contained a pair of mitts and a headtorch. This is not ideal if you're intending to climb with the pack on..."

This is either a problem with the fit (pack too long, user error) or the design (maker error), or possibly the packing. But either way it's intolerable on a climbing pack, especially at this price.

I've always liked Crux's aesthetic and direction, but on the two items I've bought, there was at least one basic, significant flaw (Flak jacket hood too small/tight, Napoleon zips badly designed, Flak trousers shorter than advertised, waistbelt clip broke) that severely affected their usability.

So I've just never been able to justify paying their prices again. I do wonder if they bite off more than they can chew, in terms of executing all they try to achieve.