Arc’teryx Acrux LT GTX hiking boot review: lightweight and precise

The Arc’teryx Acrux LT GTX is the most technical boot in the highly regarded Canadian outdoor brand’s current footwear line-up. It’s a modern climbing and mountaineering boot, designed to offer precision and plenty of heel-to-toe stiffness for steep terrain. It’s primarily designed for three-season alpine conditions, balancing protection and durability with remarkably low weight – but does it make the grade as one of the best hiking boots available today? Read on to find out how we rated it after testing the boots extensively in the hills, valleys and peaks of North Wales.

Arc’teryx Acrux LT GTX hiking boot: specifications

• Weight per boot 650g (size UK 9)
• Upper Superfabric Polyester Weave, rubber toecap and TPU rand
• Membrane Gore-Tex
• Sole Vibram Litebase Mont
• Sizes UK 4.5-12.5 (Unisex)

Arc’teryx Acrux LT GTX hiking boot: Design and features

This is a sleek and stylish boot that features some innovative technologies. The design is focused on providing maximum technical performance at minimal weight. And the Acrux LT is remarkably lightweight for a B2 mountain boot, tipping the scales at just 650g (23oz) per boot in a men’s size UK 9/US 10. Few boots offer such technical capability at such low weight, with the possible exception of the new Mammut Taiss Light Mid GTX and perhaps the Scarpa Ribelle Lite.

The Acrux LT is built on a Vibram Litebase outsole, using the tried and tested Mont lug pattern, with an extended climbing zone at the toe for efficient placement and excellent contact grip. Litebase is a new technology from the Italian rubber manufacturer that effectively reduces the sole thickness by 50% and therefore the overall weight of the sole unit by around 30%.

The midsole is comprised of a 3mm carbon fibre shank embedded in PU foam rubber. This ensures plenty of stiffness and stability underfoot with minimal weight, while the addition of PU offers durable cushioning. A plastic welt insert at the heel enables the boot to be used with C2 semi-automatic crampons.

The uppers are made from an ultralight woven polyester fabric called ‘SuperFabric’, designed to be flexible but exceptionally abrasion resistant. Low profile ‘to-toe’ climbing-style lacing ensures a close, precise fit, with quality metal hardware used for the upper triple sets of lace hooks.

High-wear areas like the heel and toecap are also overlaid with a TPU film. This offers further resistance to abrasion and impacts but saves considerable weight compared to a traditional rubber rand.

The boot is not insulated but is lined with a waterproof-breathable Gore-Tex performance comfort membrane. The tongue is also gusseted to prevent moisture ingress and help stop grit and other debris from finding its way inside.

Arc’teryx Acrux LT GTX hiking boot: Performance and comfort

This boot’s stiffness makes it a very competent and capable performer on steep ground, enabling you to edge with confidence. The highly tapered toe is also an ideal shape for jamming into small rock pockets. That front climbing zone under the toe also works well on a variety of different types of rock. You get plenty of feel too, which makes for good precision – it’s easy to tell where you’re putting your feet. As such, it’s a great boot for technical climbing and scrambling.

It works just as well with a crampon fitted for snow and ice too, which again is largely down to the boot’s stiffened midsole. The pronounced heel welt works well with common C2 clip crampons like the Grivel G12 and the Black Diamond Serac, and we got a secure fit with no issues. For prolonged cold-weather use, we’d recommend wearing heavyweight mountaineering socks (and it’s worth sizing your boots accordingly, to allow for this). That’s because the fabric uppers aren’t the warmest, and though the Gore-Tex lining provides a little insulation, you still need to guard against numb toes.

Similarly, if you’re used to B2 boots with stiff and supportive leather uppers, you might also find the fabric construction lacks a little support and protection. On test in Snowdonia, the SuperFabric weave seemed to hold up well even when subjected to sharp slate and scree, but these still aren’t the sort of boots you can go kicking rocks in.

When it comes to comfort, the Acrux LT feels more like a classic B2 boot – which is to say, it’s inevitably harder and more board-like underfoot than a highly cushioned, flexible trainer-hiker. Still, even by B2 standards it isn’t the plushest, and there are certainly more forgiving B2 boots out there. However, there aren’t many that are also this lightweight.   

The boot is very close-fitting, which is partly what makes the Acrux LT feel so agile and precise. But it’s worth noting that the slim, low volume last probably won’t suit those with wider feet, especially if you prefer a roomy toe box.

Arc’teryx Acrux LT GTX hiking boot: overall verdict

Despite a couple of drawbacks, the Arc’teryx Acrux LT is still an impressive package, with a precise feel that delivers superb climbing performance, with or without a crampon fitted. It’s remarkable that such a lightweight boot is also so technically capable. The flipside? Cushioning is fairly spartan and the fit is narrow, both of which make it relatively unforgiving on long walk-ins. As such, we reckon this is a boot best suited to ‘done in a day’ Alpine-style mountain missions.