Walking Boots

Arc’teryx Acrux LT GTX Boot | Review

A streamlined yet impressively lightweight B2 alpine boot for climbing and scrambling that delivers loads of technical precision on rock and ice

The Arc’teryx Acrux series currently comprises the most technical boots in the Arc’teryx lineup. There are three models in the range – the trekking-focused Acrux TR, the minimalist yet capable Acrux LT and the pinnacle Acrux AR.

We’d class the Acrux TR as a classic ‘three-season boot’, while the AR is a winter-ready, four-season insulated mountain boot with a removable liner. The Acrux LT sits somewhere in the middle of the pack. It’s a sleek and streamlined climbing and mountaineering boot, perfect for three-season alpine use. The focus here is on precision and feel on steep rock and ice, with plenty of heel-to-toe stiffness that enables the Acrux LTs to be paired with C2 crampons. But the boot’s real USP – as that ‘LT’ (‘Lightweight’) acronym suggests – is their remarkably low weight.

Materials

As we’ve come to expect from the Canadian outdoor brand, these boots utilise cutting-edge materials and design.

OM editor Will using the Acrux LT on a scramble in Scotland. Photos: Dave Macfarlane

Let’s start from the bottom up. The Acrux LT is built on a Vibram Litebase outsole, the latest 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%. Underfoot, the boot uses Vibram’s tried and tested Mont lug pattern, with an extended climbing zone at the toe for optimum contact grip.

The midsole features a 3mm carbon fibre shank embedded in PU (polyurethane) foam rubber, with a compressed EVA overlay. This ensures plenty of stiffness and stability underfoot with minimal weight, as well as durable cushioning. A plastic heel insert at the rear ensures compatibility with C2 semi-automatic crampons.

“Despite its considerable technical capabilities, the Acrux LT is remarkably lightweight for a B2 boot.”

The uppers are made from an ultralight woven polyester fabric called ‘SuperFabric’, which is designed to be flexible but exceptionally abrasion resistant. Low profile climbing-style lacing extends down the vamp almost to the toe, just like you’d find on a rock shoe. The lower eyelets are almost completely hidden for a cleaner look and a no-fuss design that works particularly well with crampons fitted or when tight, precise footwork is needed. The upper triple lets of lace hooks employ metal hardware in black powder-coated steel.

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.

All this means that despite its considerable technical capabilities, the Acrux LT is remarkably lightweight for a B2 boot. It weighs in at a mere 650g (23oz) per boot in a men’s size UK 9. The only rival that undercuts this is the Mammut Taiss Light Mid GTX, which isn’t quite as protective or as stiff.

Features

If you’re used to B2 boots with stiff leather uppers, these will feel refreshingly supple and flexible. Some might want a little more structure, but the SuperFabric weave does offer a decent level of protection from sharp slate and scree. The toecap is also nice and beefy.

The boot is built on a close-fitting last with a narrow toe, which is what makes the Acrux LT feel so agile and precise. However, it probably won’t suit those with wider feet, especially if you prefer a roomy toe box. It’s a boot built for scrambling and climbing, not for long, easy hikes.

When it comes to comfort, it feels more like a classic B2 boot – inevitably, it is less forgiving than a flexible, cushioned trainer-hiker. But even by B2 standards it isn’t the plushest. We’d put this down to the thinner Litebase sole unit. The upside is that you get a very lightweight boot, so in the long term, it’s likely to fatigue the foot less. You get plenty of feel underfoot too, which makes for good precision – it’s easy to tell where you’re putting your feet.

“On steep ground, the Acrux LT is a very competent and capable performer”.

The stiff sole is great for edging and the low-profile toe is the ideal shape for jamming. It also comes into its own when you fit a crampon and start to tackle snow and ice. The only thing to note for winter use is that these boots aren’t insulated and the fabric uppers aren’t the warmest. The Gore-Tex lining helps somewhat but you still need to guard against numb toes. In very cold conditions, wear thick mountaineering socks (it’s worth sizing your boots accordingly, to allow for this). Or for prolonged cold weather use like Scottish winter climbing, you might be better served by the Arc’teryx Acrux AR.

But if you’re looking for a neat, capable B2 boot for summer alpine and general winter mountaineering adventures in the UK, this is one of the lightest and most technically proficient performers around.