Several innovations stand out in the design:
Different versions are available for both the Acrux and the Bora Mid; the liner is either stitched to the upper or is separate and completely removable. The removable liner offers several advantages: it can be dried out, cleaned or swapped for another more suitable liner depending on the climate.
The liner gives a sock-like fit; it has a micro-mesh inner face that is highly air permeable and it stretches to the shape of your foot and is made with a specific thickness that, according to the brand, provides greater comfort and cushioning.
As we mentioned, the upper is constructed in just one piece of thermolaminated material, for a better fit and to eliminate friction. The material is hydrophobic, which prevents it from absorbing humidity and gaining weight. Reinforcements in areas prone to abrasion protect both your feet and the boot.
The most innovative feature, is definitely the absence of the tongue. This prevents common problems in this area, such as pressure points and uncomfortable lumps.
The Acrux has a VibramÂ® Megagrip sole for use on all kinds of terrain, while the Bora Mid uses the same VibramÂ® Megagrip compound, but with a more aggressive design to provide a better grip on mountain terrain.
When we first held this boot, our initial reaction was to express doubts about the new design elements. Certain details, for example, such as the absence of grommets in the lace holes: would the laces not stretch the shell or allow water or dirt to enter the boot? We also had misgivings about the comfort and performance of the new shell + liner system.
We mainly tested the Bora Mid 2 boot, with the removable liner, which can be considered to be at the top of the new range. We found that the Acrux shoe works really well, but obviously the differences are fewer with respect to a normal system.
It's not particularly easy to get on, until you get the hang of it and it may feel slightly uncomfortable to some and choosing the right size is extremely important. We found the easiest way to put the boot on was to put the liner into the boot first. The alternative; putting the liner on your foot first, was trickier.
Comfort of the liner
It is really comfortable and fits like a sock, without being too tight.
Although there are no seams on the inside of the liner and it provides exceptional comfort, there is a seam at the back of the heel. This doesn't cause discomfort but made us wonder how it would stand up to prolonged use.
One important thing about the liner is that it has a comfortable stiff inner sole, designed for use as a slipper in mountain huts or hostels.
We found that the right way to tighten the boot laces is after taking a few steps. You'll then find that the boot adjusts perfectly to your foot and you can tie up the laces properly.
Once you get over the initial differences, the boot feels really comfortable and its cushioning and lack of pressure points are certainly noticeable, together with the light tongue area and the fact that there are no pressure points.
Even though the boot holds the heel securely, it is extremely flexible and this makes it more suited to paths and trails than abrupt or technical mountain terrain. The ankle protection gives extra support and abrasion-resistance against rock, etc. It gives stability yet doesn't impede movement. This has its pros and cons, of course, depending on the kind of activity you choose. But overall, we can say it gives stability for general use but doesn't offer the level of support of a mountain boot when crossing a steep slope or in deep snow. On paths, however, or on large rocks, like the ones shown in the video of the Anayet area, it gives outstanding performance.
The sole is very efficient and it's an agile boot. We tried it in Spring snow conditions, on dry and wet rock, mud and dirt and it gave excellent results. The boot's agility is similar to that of a trekking shoe; but with greater protection in the ankle area. However, in spite of it's appearance, it's not the same as a 3-season mountain boot on abrupt and technical terrain.
Impermeability and breathability
The waterproofing capacity and breathability of this boot is, without a doubt, one of its strongest points. The liner not only makes it waterproof but, thanks to the close fit round the ankle, it prevents water from entering the top of the boot, when crossing rivers, for example. We really noticed the increased breathability produced by the air channel between the shell and liner and the more exposed tongue area. We tried it on a particularly warm day and it gave great results.
One of the doubts we had at first, about water getting in between the liner and the boot, became unfounded as we walked through rivers, puddles, etc. When walking on snow, mud and gravel the results were just as good.
However, we did find that these positive results were the result of the boots being properly laced. If the laces had been loose, water would probably have got in between the liner and shell. For this reason, we stress the importance of choosing the right size and lacing correctly.
Although at first sight the boots appear to have certain âdelicateâ zones, such as the lack of grommets in the lace holes, after several uses it was clear that the materials showed no signs of weakness. It's more of an impression caused by these state-of-the-art materials which are lighter and finer, yet are able to stand up to continuous abrasion against rocks, stones, etc.