Altra oz / 339g review

We recommend the Altra oz / 339g as an excellent hiking companion for:

• Hikers in the market for an incredibly comfy zero-drop hiking boot for less challenging terrains
• Speedy hikers looking for a nimble and lightweight boot that feels more like a trail runner underfoot
• Year-round adventurers who need a boot that performs consistently from blustering summer treks to frigid winter hauls. 
• Casual hikers looking for a boot that's good for long hauls as well as quick strolls through the park or around town
• Toebox width at the big toe 

While the oz / 339g provides excellent traction on dirt trails, we felt decidedly less surefooted on gravelly or rocky trails. For advanced hikers who frequently traverse more technical trails, we recommend the more aggressive La Sportiva Ultra Raptor II Mid GTX instead. 

The oz / 339g is weatherproof, but not waterproof. So while the boot will keep our feet relatively dry during rainfall, it won't help much when wading through riverbeds or streams. For those who need to keep their feet dry, especially in the colder months, we recommend the Hoka Trail Code GTX instead. 

The flexibility of the oz / 339g certainly contributes to its comfy, trail-shoe vibe, but also detracts from its stability. Especially as the mile markers wear on and foot fatigue sets in. Backpackers looking to schlep heavy loads across vast distances will be better served by a more stable boot like the much heavier but supportive Salomon Quest 4 GTX.

The instability of the oz / 339g will feel even more pronounced for those with narrow feet who will have to put in more effort to stabilize their landings as their feet swim around in the toebox. For a more snug alternative, we recommend looking into the also lightweight Hoka Anacapa Mid GTX instead. 

To see how breathable the oz / 339g is, we pumped it full of smoke and observed how easily it was able to vent from the boot. As we can see from the footage, the smoke was only able to escape through the oz / 339g's porous, semi-gusseted tongue while the rest of the upper remains relatively airtight. This leads us to give the oz / 339g a breathability score of 2 out of 5. This means that the boot will certainly feel stuffy during hikes on sweltering summer days but still has some level of airflow to keep it from becoming a stinky foot sauna. 

The Number of shoes, on the other hand, lets the smoke dissipate rather evenly throughout the shoe, making it much more suited for hikes on hot, dry days. 

Inspecting a cross-section of the mostly mesh upper, we see that it entirely blocks out the backlight, thus confirming the insular, weatherproof nature of the shoe. Just as light isn't able to peak through any pores of the upper, water is similarly repelled unless the boot gets drenched. 

To see how the mech is able to repel water so efficiently, we took a look at it under the microscope which reveals an incredibly uniform and dense weave pattern with almost no gaps between the braids.  

To simulate extreme wear and tear, we subjected the oz / 339g to a series of Dremel tests, starting with the toebox. Spinning at 5K RPM, we set the tool's abrasive element to an unreinforced section of mesh with 3.2N of force.

While we were able to pierce through the mesh by the end of the twelve-second test, the hole left doesn't span the entire point of contact and the overall integrity of the toebox wasn't greatly affected, so we give the oz / 339g a middle-of-the-road toebox durability score of 3 out of 5. 

The heel counter proved to be an even better adversary to our Dremel which merely skated off the lining material and left the padding beneath intact. 

This stellar performance leads us to give the oz / 339g a perfect 5 out of 5 for heel padding durability. 

The MaxTrac rubber compound that makes up the outsole gave us a durometer reading of 85.5 HC which is right around our current lab average. This usually denotes a good mix of grip and durability, the latter of which will be tested in the next section. 

This time spinning at 10K RPM, we set the Dremel against one of the lugs which immediately kicked up a flurry of rubber particles. Not a promising sign. 

After twenty-two seconds of grinding, we measured the indentation left behind with a tire tread gauge and found that 1.2 mm of material was lost to the test. This makes the oz / 339g's outsole less durable than the average hiking boot which loses less under similar circumstances. This further confirms that this boot isn't well-suited for harsh, gravelly trails which will erode the lugs at a much faster rate than softer dirt trails. The Excellent attention to detail Performs consistently in cold conditions. 

The oz / 339g's outsole boasts less rubber than average at only 2.1 mm thick according to our caliper measurements. While this doesn't do the boot any favors in terms of durability, it does contribute to its lightweight frame. 

The oz / 339g is a lean, mean, trail-crushing machine that tips our scale at only 12 oz (339g). 

As such, the oz / 339g feels incredibly feathery underfoot which not only makes it great for long hikes with lots of ascents and descents, but also unburdensome enough to support light jogs for whenever the need for speed kicks in. 

We measured the oz / 339g's stack to be 26.4 mm thick at the heel.

This is significantly shorter than average but still has plenty of foam underfoot for us to enjoy well-cushioned landings over the course of testing this boot. 

Naturally, we expect the forefoot stack to match the heel but there's a bit of a discrepancy with the oz / 339g. Using the measuring guidelines set by World Athletics, we measured the oz / 339g's forefoot stack to actually be 23.8 mm thick. So, technically, it's not a true zero-drop boot. 

This amount of foam underfoot is on par with our current lab average and is enough to effectively mute out the harsh terrain below. 

The difference in our stack measurements means that the oz / 339g actually sports a 2.6 mm heel drop. This is still a more parallel-to-the-ground experience than most hiking boots offer and will only be noticeable to true zero-drop purists. 

Pressing our durometer against the midsole yields a reading of 22 HA. This level of softness provides a balanced level of cushioning 

Apart from providing good impact dampening, the midsole is also quite responsive. It has a springy rebound that feels more like a trail running shoe that gives us a little extra pep in our step while hiking in this boot. What's more, it means that we could break out into a jog at a moment's notice and comfortably scamper along the trails like a breeze. 

We placed the oz / 339g in our freezer for twenty minutes to see the effects of cold conditions on the midsole. Once appropriately chilled, we pressed our durometer against it once more and got a much softer-than-average reading of 25.3 HA. This 14.8% increase in firmness means that the oz / 339g performs very consistently no matter how frosty it gets and will provide balanced cushioning all year round. 

We measured the insole to be 7.4 mm thick which is quite a bit thicker than our current lab average. This provided us with great arch support and a cushy footbed to sink into that really elevated our levels of comfort while testing this boot. 

The oz / 339g, for all its comfort, isn't a very stable shoe as demonstrated by how much lateral movement it allows as we shift our weight from side to side. This made traversing uneven terrains a little more challenging as we had to be more mindful of our steps and make lots of foot adjustments for balance. While this is fine when it comes to day hikes, we would recommend a more stable shoe like the Keen Pyrenees Add a shoe. 

The oz / 339g put up a fair amount of resistance as we bent and twisted the shoe in our hands during our manual assessment, leading us to give it a somewhat stiff torsional rigidity score of 4 out of 5. This allows the boot to maintain a relatively level base underfoot that promotes stable landings while hiking along. 

The oz / 339g's heel counter is somewhat flexible and earns a middle-of-the-road stiffness score of 3 out of 5. So while it does provide a secure lockdown that comfortably holds our heel in place, it doesn't do much to mitigate the rearfoot from rolling laterally. 

The oz / 339g's midsole is about as wide as our current lab average at 110 mm according to our caliper measurements. This gives us a good amount of platform for relatively stable landings. 

Back at the heel, we found the oz / 339g's midsole to be narrower than average at only 84.4 mm wide. This didn't really present us with any issues while testing, but those more accustomed to a wider base at the heel should look into the Merrell Moab 3 Mid GTX instead. 

We secured the oz / 339g to our workbench and found that 29.9N of force is needed to bend it 90 degrees, making it more flexible than the average hiking boot. 

The flexibility of the oz / 339g is thanks in part to the configuration of its lugs which are designed to line up with the bones of our foot, allowing the shoe to bend along with the natural flexion of our foot with relative ease. 

This certainly plays a role in how comfy and forgiving the oz / 339g feels underfoot, however it does come at the expense of stability, especially when carrying a heavy pack.

We also repeated the flex test after leaving the oz / 339g in the freezer for twenty minutes and found that it only became 13.9% stiffer when exposed to the cold. In fact, with a post-freezer requirement of 34.1N to bend the boot to the desired point, the chilled oz / 339g is more flexible than the average boot at room temperature. This incredibly consistent performance means that the boot should be just as pliable and forgiving on the foot during frigid winter hikes. That said, we still wouldn't recommend trudging through heavy snow or ice in this boot. 

The oz / 339g's lugs are 4 mm thick according to our caliper measurements, putting them on par with our current lab average. 

These multi-directional, chevron-shaped lugs provided us with excellent traction during our test hikes on dirt trails and well-manicured park trails. 

However, the boot did let us down when we tested it on more technical, gravelly trails where we felt decidedly less surefooted in our strides. We also recommend avoiding slick or muddy surfaces in this boot. 

At 97.8 mm wide at its widest point according to our caliper measurements, the oz / 339g's toebox is narrower than our current lab average. This is out of the norm for Altra which has come to be known for their roomy and accommodating toeboxes. This will feel a little snug for those with broad feet, but should still be somewhat comfortable while providing a secure lockdown. 

The oz / 339g does still achieve that natural foot-shaped silhouette we've come to love from Altra footwear by barely tapering towards the toes. 

Measuring 91.1 mm wide around the big toe, the oz / 339g gives us plenty of room to splay out comfortably whether walking or jogging in this boot. Conversely, having so much internal real estate isn't ideal for those with narrow feet as they will likely shift around within the boot when traversing uneven terrains, which takes a toll on stability and can exacerbate foot fatigue. 

Unlike many other hiking boots we've tested so far, the oz / 339g's tongue is only semi-gusseted. While this might help in shaving off a few grams from the overall weight, it does mean that little bits of grit and debris did occasionally make their way into the boot during our test hikes. 

At 9 mm thick according to our caliper measurements, the oz / 339g's tongue is slightly less padded than our current lab average. It's still cushy enough to feel incredibly comfortable across the instep and effectively protects us from lace bite while testing this boot. 

There's a cord-like finger loop at the heel of the oz / 339g to help pull the boot on.

However, despite this feature, we still found the boot difficult to squeeze into without loosening up the laces significantly. 

The oz / 339g's insole isn't glued in so it can easily be replaced with a custom orthotic if necessary. 

The oz / 339g doesn't feature any reflective elements, so we don't recommend walking along dimly lit roads at night without additional high-vis gear.