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Reviews > Packs > Internal and External Framed Backpacks > Black Diamond Axiom 40 backpack > Test Report by Kurt Papke

Black Diamond Axiom 40 Backpack

Test Series by Kurt Papke

Initial Report - March 20, 2012

Field Report - June 19, 2012

Long Term Report - August 24, 2012

Tester Information

Name: Kurt Papke
Age: 58
Gender: Male
Height: 6' 4" (193 cm)
Weight: 235 lbs (107 kg)
Email address: kwpapke at gmail dot com
City, State, Country: Tucson, Arizona USA

My backpacking background is a combination of hiking in Minnesota where I have lived most of my adult life, and Tucson, Arizona where I moved to take a new job about three years ago.  I have always been a "comfort-weight" backpacker, never counting grams, but still keeping my pack as light as easily attained.  My typical load in a 4600 in^3 (75 L) pack is 40 lbs (18 kg), so the Axiom 40 pack will be a big change for me.

Initial Report

Product Information

Manufacturer: Black Diamond Equipment

Axiom 40

Photo courtesy Black Diamond Equipment

Axiom 40
Year of manufacture: 2012
US $ 149.95
Manufacturer website:
Color tested:
Blue steel, also available in Coal black
210d Nylon Ripstop & Twill, 70 X 210d Dobby
Size tested:
Large, also available in medium
42 L, 2,563 in^3 (Large)
40 L, 2,440 in^3 (Medium)
1.2 kg (2 lb 10 oz) - Large
1.15 kg (2 lb 8 oz) - Medium

Measured: 1.31 kg (2 lb 14 oz)

Note the roughly 4 oz (110 g) difference between measured weight and that given by the manufacturer.  I weighed the pack several times on a digital kitchen scale and obtained very repeatable results.

The features listed by the manufacturer include:
  • reACTIV suspension with OpenAir backpanel
  • Top-loading roll-top closure with removable top pocket for quick and clean volume adjustment
  • Soft, breathable 3D mesh on hipbelt and shoulder straps
  • Trekking pole/ice axe loops
  • Dual hipbelt stash pockets, side stretch pockets and front compression stretch pocket
  • Hydration compatible

Initial Inspection

The pack arrived in excellent condition with no apparent shipping damage.  A brief visual inspection turned up no noticeable workmanship defects.

Main compartmentAfter unbuckling all the straps and unrolling the top closure my first impression was "wow, this is a good-sized pack".  I was concerned when I signed up for this test that I was going to have to severely constraint my gear, but I was relieved when I saw the cavernous main compartment as shown in the picture at left.

The callouts in the picture show the buckles for the roll-top closure.  This setup works similar to a roll-top dry bag.

There is only one hydration port, in the center of the pack.  Most of my prior packs have had two ports, but this looks like it will work fine.

Below the port is a hook-and-loop closure strap to suspend a hydration bladder.  I like the idea of something more certain than just a hook, but its use will be constrained to bladders that have a wide enough slot for the strap.

Below that is a thin elastic hold-down strap for a hydration bladder, as opposed to a pouch like my other packs have.  The strap is more flexible in the size of bladders it will accommodate, but has the disadvantage that it will not protect a bladder from abrasion resulting from rubbing against the contents of the pack, nor will it prevent any condensation from a cold bladder wetting the pack contents.

Pack lid interiorThe photo at right shows the inside of the pack lid.  It has few features, only a keychain clip to secure car keys.  Frankly, this is all I ever need.  I have other pack lids that have zippered compartments, map pockets, etc. that I rarely used.

There is only one lid zipper, and it worked smoothly.

I normally carry my Jetboil stove and lunch/snacks in the lid.  My Jetboil fit just fine with plenty of space for food.
Hipbelt pockets & sternum strapThe photo at left shows the sternum strap with a built-in emergency whistle.

Below the sternum strap is a hipbelt pocket with my GPS inside.  The size of the pockets were a bit disappointing for me, I hoped they would be a bit larger.  In addition to my GPS, I could probably fit some lip balm and maybe a very small snack.

My pocket camera barely fits into the other pocket.  It'll be interesting to see how easy it is to get the camera back in the pocket when the hipbelt is under tension and curved from my hipbones.

The various webbing straps that are visible in the picture at left show the "sheen" that they have, which seems to coincide with how smooth they feel to the touch.  I don't feel that they will abrade my skin, they are very slippery.

Side pocket with Nalgene bottleThe photo to the right shows my trusty Nalgene water bottle in the right side pocket.  Though lightweight hikers dismiss this type of bottle as unnecessary weight, I like them for preparing hot beverages, use as hot water bottles at night, and rehydrating food while hiking during the day.  They are the standard by which I measure the utility of side pockets.

As can be seen from the photo the bottle fits, and there is a nice strap to hold it securely in place if I feel the need.  The right side of the picture is the back of the pack, i.e. the side that is towards my body where I will be reaching from.  Quite a bit of the bottle is exposed, which causes me some concern about how secure it will be without the strap in place.  It may be that I will have to trade off ease of access with the pack on for peace of mind about not having the bottle fall out on the trail.  Time will tell.

Initial Use

I loaded up the pack with the bulky items that normally accompany me on a backpacking trip: sleeping bag in its compression sac, hammock and tarp.  To be pessimistic on my food load, I threw in my bear canister.  My windshirt went into the front pocket.  Dang, it seemed like the pack was only half-full!  I strapped everything down and threw it on my back.  After a few minutes of tightening straps I was good-to-go.  I really like the mechanical leverage from the hipbelt strap loops; it really allows me to crank down and get as much weight on my hips as possible.

The pack felt really good on my back.  It seemed exceptionally stable, comfortable and did not interfere with my arm  swing in any way.  The lower lumbar pad that supports the weight of the pack on my lower back did seem a little narrow; I'll keep my eye on this to make sure I don't have any pressure points.

I reached around to get the Nalgene out of the side pocket and couldn't get the buckle unsnapped.  Looks like this will take some experimentation.

Next I removed my camera from the hipbelt pocket.  This took some doing as the pockets are way off to the backside, and they were really tight.  I was able to get my camera out, but could not get it back in without undoing the hipbelt clasps.


I am excited to get the Axiom out into the backcountry and put it through its paces.  This pack feels really great.  Some initial reactions include:


  • Much more spacious than I anticipated.  My other packs have many more compartments and pockets, which while helping to organize my gear they do waste a lot of space and weight.
  • The hipbelt does a great job of getting the weight off my shoulders and has a nice feel.  It is very easy to tighten to get a good fit.


  • It may take me a while to figure out how to optimally use the side water bottle pockets, i.e. how to secure the bottles and what size and type works best.
  • The hipbelt pockets do not seem to have as much utility as I had hoped.  They are quite small, and not easy to reach.
This concludes my Initial Report.

Field Conditions

In the following table the base weight does not include the containers for water and food.  I weighed the pack before and after loading it with consumables and their bags, bottles and reservoirs.

Terrain/trail type
Altitude range
Base Weight Total departure weight
March 30-April 1, 2012
Santa Catalina Mountains in the Coronado National Forest near Tucson, Arizona
Romero Canyon
19 mi
(31 km)
Sonoran Desert to Ponderosa pines
Sunny, nighttime lows about 45F (7 C), daytime highs 90 F (32 C)
2600-6200 ft
(790-1890 m)
18.5 lbs
(8.4 kg)
34.5 lbs
(15.7 kg)
April 20-22, 2012
Rincon Mountains in Saguaro National Park near Tucson, Arizona
Miller/ Heartbreak/ Turkey Loop
23 mi
(37 km)
Sky Island ridgelines: from rocky desert canyons to Ponderosa Pine woodlands
Sunny, 40-95 F
(4-35 C)
4240-7920 ft
(1290-2410 m)
18.1 lbs
(8.2 kg)
36.5 lbs
(16.6 kg)
June 15-16, 2012
Santa Catalina Mountains in the Coronado National Forest near Tucson, Arizona Samaniego Ridge
8 mi
(13 km)
Sky Island ridgeline Sunny, 60-85 F
(16-29 C)
5000-7100 ft
(1520-2160 m)
15 lbs
(6.8 kg)
39 lbs
(17.7 kg)

June 21-23, 2012 San Francisco Peaks in the Coconino National Forest near Flagstaff, Arizona Mt Humphreys
25.6 mi
(41.2 km)
Forests to mountain peak tundra Sunny, 50-80 F
(10-27 F), very windy especially near the peak
8050-12562 ft
(2450-3830 m)
17 lbs
(7.7 kg)
35 lbs
(15.9 kg)
July 27-28, 2012
Santa Rita Mountains in the Coronado National Forest near Tucson, Arizona
Vault Mine
5 mi
(8 km)
Sky Island canyon
Partly cloundy, 60-85 F (16-29 C), rain at night
5500-7300 ft
(1675-2225 m)
Not measured
30.6 lbs
(13.9 kg)

Field Report

Romero Canyon Trail

Axiom on the AZTThis is the first trail I ever hiked in Tucson, but all my trips so far have been day hikes which limits how much I can see.  I wanted to get out for a weekend and didn't want to drive too far, so I drove to the trailhead just 10 minutes from where I work on a Friday afternoon.  I also thought this would be a good test for the pack given the large elevation gain/loss involved, as this trail starts in the Tucson basin and goes all the way to the summit of Mount Lemmon, though I didn't go quite that far.

I had loaded up the Axiom with as light a base weight I have ever backpacked with, but with the water I added it was still on the high side for Black Diamond's recommendation for this pack.  I didn't think I would be dry camping at least the first night, but I wanted to see how well the pack carried my 3 L (3 qt) Platypus reservoir (see my review of the Platypus Insulator system on this website) and a full Nalgene.

I carry a Canon Powershot SX120 IS camera which is reasonably compact, but with the substantial zoom lens it contains it doesn't fit very well in the Axiom hipbelt pockets.

Also visible in the photo is the drink tube from my Platypus, secured to the sternum strap buckle with an S-biner.  This worked extremely well.  One of the pack features not listed in the manufacturer's literature are two elastic bands on the top of the shoulder straps that hold the drink tube away from the neck.  Overall I was extremely pleased with use of the reservoir with the pack with one exception: on Friday afternoon I believe the reservoir was "sweating" some from the cold water, and the condensate dripped down wetting some of the pack contents.  Fortunately all my key gear is packed in dry bags, a custom I have not been able to break from my long years of Minnesota backpacking.

Axiom 40 from the rearVisible in the photo at right is the front pack configuration.  No, the camera was not tilted, I was.  In the left side pocket is my Exped Multimat (see my review of this pad on this website).  Since it is quite long even after being folded in half and rolled up, I always carry it on the outside of my pack.  This worked very well.

In the right pocket is my Nalgene, strapped in so it would not fall out.  I accessed it only on breaks when I removed my pack, which was perfectly adequate given I could take a sip of water any time from the reservoir.

The front pocket holds a lot more than I initially thought.  The fabric is very stretchy, and the black band on the top edge is slightly less elastic which keeps the contents from falling out.  Every time I thought about stuffing something more in there I thought "No, it won't fit", but it did!  It doesn't look too attractive all bulgy and all, but I wasn't concerned.

The hipbelt pockets were a real disappointment.  About all I could use them for was my cell phone and a candy bar.  My GPS fit in there initially, but it was just too hard to get in and out.  Part of the problem is the pockets are positioned right over my hip bones where the belt has a high curvature, so anything that is not flexible doesn't want to go in or out of the pockets.

The pack lid was very roomy.  I was able to carry my Jetboil, snacks for a day, my headlamp, car keys, and a few other small items.

This pack carries wonderfully.  Even though I was slightly overloaded from the manufacturer's recommendation I still felt very comfortable carrying the pack all day long.  It fits very tightly against my spine, almost like it is an extension of my skeletal structure.  The hipbelts held the weight of the pack up off my shoulders perfectly -- my shoulders never got sore all weekend.

The pack was plenty big for a three-day hike, and I carry a lot of food.  I am a big guy, and when I am backpacking I consume vast quantities of food, hence the substantial delta between my base weight and fully loaded weight (well a lot of that is water too).  I never felt like I had to cram my gear into the pack, which is surprising since I am accustomed to much larger packs.

The roll top closure worked very well for me.  I've never had a pack with one of these before, and I really like it.  No straps to tie down, just roll and snap.  Clean and simple.

I did not use the pole/ice ax loops and tie-downs on this trip.  When I first started backpacking I would often have to stow my trekking poles by mid-afternoon as my arms would get tired, but now that my body is conditioned to using them I propel myself with the poles all day long.  I can only see myself using them if I needed to do a scramble that required use of my hands, but time will tell.

Miller/Heartbreak/Turkey Loop

Pack Tap on the reservoir hanger loopThis hike is a popular traverse of the Eastern slopes of the Rincon Mountains of Saguaro National Park that had been on my radar for some time.  I decided I would try and trim my baseweight and bulk a bit for this trip, but I still needed to be prepared to carry a fair amount of water as I didn't know if I would be dry camping the first night.

I substituted much of my water-carrying gear from the prior hike; the Nalgene was replaced with a Platypus 1 L soft bottle, and the reservoir was replaced by a Pack Tap (see my review of the Pack Tap on this site).  The Axiom actually accommodated the Pack Tap much better than my other backpack, because it was not constrained to a reservoir pocket and the hook-and-loop strap fit the slot in the top of the Pack Tap perfectly as can be seen in the photo at left.  The only Axiom feature that did not work well for this was the elastic reservoir hold-down strap -- it was just not wide enough to allow for the tilted rectangle shape of this reservoir.  This was of no consequence, as the reservoir was packed so tight it was not about to go anywhere.  The linkage of the reservoir strap is firmly anchored to the metal pack frame, which does a great job of transferring the weight to my hips and off my shoulders.  Though I was carrying close to 6 L (6.3 qt) of water, my shoulders did not get sore.

On the negative side the hook-and-loop strap was just not capable of holding the weight of the filled 4 L (4.2 qt) Pack Tap.  Every time I went to retrieve the filled reservoir or to retrieve something else from the pack the strap had given way and the reservoir was sitting at the bottom of the pack.

Another adjustment I made on this trip was to pack my sleeping bag vertically instead of my normal horizontal spot at the bottom of the pack.  As can be seen in the rear photo from the Romero Canyon trip the bottom of the Axiom is very narrow and my bag could not be crammed in straight and it looked very askew.  By putting two stuff sacs of gear vertically the bottom space of the pack was fully utilized and didn't look distorted.

Another major adjustment was to substitute my Hennessy hammock and SuperShelter for my Warbonnet Blackbird, Siltarp and Multimat combo.  This allowed me to use both Axiom side pockets for Platy soft bottles because all components of the sleep system fit inside the backpack instead of using up a side pocket for the mat as depicted in the rear photo in Romero Canyon.  The Platy soft bottles worked much better in the side pockets than the Nalgene, especially when they were not totally full.  The practice I fell into was strapping them into the side pockets when they were completely full, then leaving the strap unbuckled after taking one big drink when they no longer stuck up so high.  It was very hard for me to rebuckle the straps without taking off the pack, and once the bottles were not completely full they seemed quite secure without the straps.

Samaniego Ridge

Axiom on Samaniego RidgeThis was my highest total pack weight so far with the Axiom, due to the 8 L (8.5 qts) of water I was carrying.  I was expecting to be out for two nights, but that was not to be.  On the other hand this was my lowest base weight with the Axiom.  I had only lightweight baselayers to sleep in, no fleece or any other cool-weather or rain gear.

The Samaniego Ridge trail is one of the less-used paths in the Catalinas, as it is poorly maintained and has a reputation for difficulty which is well-earned.  The northern trailhead is also notoriously hard to get to as a high-clearance 4WD vehicle is required.  Fortunately my Jeep Wrangler is up to the challenge, and I arrived at the trail head late Friday afternoon.

I hiked up the ridgeline far enough to get up to the tree line.  The Sky Islands of southern Arizona are backwards from what I thought about mountain terrain before I moved here: the lower areas of the mountains are treeless due to the low rainfall and high temperatures.  The trees start to appear at about 6000 ft (1800 m).  I need trees to pitch my hammock sleeping shelter.  The pack lid was large enough to hold my Jetboil plus a Subway footlong sandwich, which is my traditional "first night on the trail" meal.  The sandwich fit OK, but arrived at camp a bit compressed.

After a comfortable night under the stars I set out early the next morning to hike up the remainder of the ridgeline.  At about 10 AM I encountered an extremely dangerous section of trail that required holding onto a rope attached to a sheer rock face, then scrambling up a very steep hillside.  I figured I could get up there OK, but I was not sure I could get down safely, and since I was hiking solo on a very isolated trail I decided to play it safe and turn around.  Thus this ended up as just a one-night instead of the planned two-night trip.

Through it all the Axiom performed admirably.  Despite the heavy total weight, the pack never felt uncomfortable.  In addition to the Pack Tap carried on the prior hike I also had my Platypus reservoir and my two 1 L platy bottles filled with electrolyte drink.  I was also carrying a new strap-mounted pocket for my GPS clipped on to the hipbelt straps as can be seen right at my waist in the photo.  I had to go through some really brushy areas where the trail is poorly maintained, and I appreciated the Axiom's tight profile which prevented snags.

Though not visible in the photo, I continue to adjust my packing to accommodate the narrow base of the Axiom.  I normally put my sleeping bag horizontally in the bottom of a pack, but it does not fit that way in this pack as can be seen in the photo above from Romero Canyon - note the big lump in the lower-left bottom.  On this trip I coiled my hammock in the bottom of the pack which fits nicely, then put my bag just above that where the pack is wider.

Finally, a word or two about the suspension system.  The Axiom 40 has Black Diamond's reACTIV system that features adjustable hipbelt pivot:


On the back side of the hipbelt is a strap for adjusting the amount of pivot, which is labeled "FREE/LOCK OUT" in the photo above.  The pack is not upside down, I believe it is lettered this way to be read from looking down from above when wearing the pack.  Pulling the strap to the front "locks out" the pivot action, and releasing the tension allows more freedom.  I haven't played with this a whole lot yet, I've left it in somewhat of an in-between setting.  As is visible in the photo this has caused some fraying in the webbing strap - not so much that I am worried about a break or tear, it is more of a cosmetic issue than anything.  However, the pack has only about 50 miles (81 km) on it so far, so it could become an issue with extended use.  During the next phase of testing I'll attempt to remember to play with this adjustment to see how it feels on the trail in the two extreme settings.


I have only three words to describe this pack: tight, tight and tight:

  1. The pack hugs my back tightly, and does not protrude out anywhere to get in my way.
  2. The contents are held tightly to the pack, the pockets do not bulge out.
  3. It is a tight squeeze to get anything in/out of the hipbelt pockets
The only other fault I have found so far is the poor weight-carrying capacity of the hook-and-loop reservoir strap.

I am very happy with the pack so far.  It carries like a dream, and I look forward to another two months of testing it.  I have been able to exceed the recommended weight capacity of the pack by a wide margin without any discomfort.

Long Term Report

Mt Humphreys

This was a 3-day 2-night backpacking loop hike consisting of the Kachina, Mt Humphreys and Weatherford trails in the San Francisco Peaks, including a summit of Mt Humphreys.  We expected to be able to replenish our water at the ski resort just before beginning our climb up Humphreys, so my departure weight actually underestimates my maximum weight by about 10%.

This was the first trip I used the trekking pole loops and attachments on the pack front.  I had a short walk from my Jeep to the campsite the first night, and needed my hands free.  They worked very well, I had no difficulty in attaching and removing the poles, and they were held snugly by the features.

The following photo shows a typical scene of the Axiom in use clambering over a down tree in an aspen grove along the Kachina trail:

Axiom on the Kachina Trail
Photo courtesy Derek Hansen

In the next photo I am getting ready to put the Axiom back on again at Fremont saddle - we did the summit (visible in the background) with packs off due to the difficult terrain and short distance:

Axiom at the saddle
Photo courtesy Derek Hansen

I should add that the lift strap on the Axiom is very nice: wide enough that it does not hurt my fingers to lift a heavy pack.  My practice is to hang my pack every night from a stubby broken tree branch to keep it off the ground and away from critters, and the lift strap worked very well for this purpose.

On this hike I did loosen the hipbelt pivot straps prior to departure.  They make a difference.  I could feel the pack adjust to my hip movement in situations as in the prior picture above clambering over a log.

Overall I was very pleased with the Axiom on this hike.  With all the water I was carrying I used every last crack of space, and certainly pushed the pack's load-carrying capacity.  I had no complaints or issues with the gear whatsoever.

Vault Mine Trail

This was an easy overnight up to a saddle point where I really enjoy the view, but had never camped.  This was my lightest total weight to-date with the pack, as I was not carrying very much food and "only" 5 L (5.3 qts) of water.  This was also the first time the Axiom had to withstand rain.  It poured after I went to bed, and though the pack was underneath my hammock and tarp, it was very windy and the rain was coming down almost sideways, so the pack got pretty well soaked.

In the morning I hung the pack from a tree branch and allowed it to dry while I had breakfast.  I was pleased to observe that by the time I broke camp and put the pack on, the back pad was quite dry, so it didn't feel clammy against my back.

This whole hike was done with the "FREE/LOCKOUT" straps in the FREE position.  The ascent and descent were quite steep, an average of about a 20% grade, and the pack handled nicely in this setting.  The terrain is depicted in the following photo which shows one of the rare spots where the trail follows a contour making the gradient visible left-to-right:

Axiom on the Vault Mine trail

Wear and Tear

At the end of my four months with the pack I examined the Axiom for any signs of wear and tear.  I turned up two:


The above picture is the back of the roll-top extension.  For scale purposes, the tear in the upper-right, the largest, is about one inch (2.5 cm) in length.  I'm not sure how this happened.  From the well-defined non-ragged edges I infer that some sharp object at the top of the pack abraded through or cut the material.  The other damage was on the lid seam:

Lid wear

This seemed to be ordinary wear-and-tear abrasion from rubbing against the buckles or other hardware.  Both issues were just cosmetic, though the seam wear on the lid, if it continues, could eventually result in an opening where small objects could fall out, but could be easily repaired in a few minutes with a sewing machine.

I should note that I do not treat my gear, especially items under test, with any special consideration.  Packs in particular get thrown around a lot, into the back of my Jeep, etc.  I examined the bottom of the pack where I have tears on my other packs from throwing them to the ground, but the Axiom was intact.


I have grown to appreciate the suspension of this pack over the last few months.  It is a great design.  I would add to my "tight" list in the summary of my field report that this pack is very durable - the only issue I had was the few small tears in the roll-top fabric and abrasion on the pack lid, and I'm not really sure how they happened.  The Axiom 40 is rugged, comfortable, light, and holds a ton of gear.  What else could I ask for from a backpack?

My bottom line is that the Axiom will be my pack of choice on 2-3 day outings for the foreseeable future.  I really like the comfort, and it has encouraged me to lighten my load.  On week-long trips I will revert to my larger packs, but I intend to use the Axiom whenever feasible.

Many thanks to Black Diamond and for the opportunity to test this product.

Read more reviews of Black Diamond gear
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