Arc'teryx Acrux AR Review

What makes the Arc'teryx Acrux AR unique is that it's the lightest double boot on the market. Instead of being a double boot made for 6000m peaks (with the associated insulation and bulk), it's a double boot made for 4000-5000m peaks. This means that this boot is much more pleasant to hike and climb in than its 6000m brethren.

Performance Comparison

Climbing

The Acrux AR climbed rock well for a double boot and was only slightly lower performing than the super-gaiter boots in our test. Ankle flexibility is essential for rock climbing; we liked that the boot gave us the option to quickly increase the ankle flex by loosening up the velcro ankle strap (this is also a benefit when employing French technique on moderate slopes). We also felt that the slightly flexible sole helped on dry rock without crampons.

On the ice, this boot's performance was average. We had good crampon fit with Black Diamond, Petzl, and some Grivel toe bails. While the ankles on the Acrux AR aren't as supportive as our favorite boots for front pointing, there was sufficient calf support for steeper pitches. We felt the same on mixed terrain or when dry-tooling; performance was not bad, but nothing special.

Our larger testers detected some flex in the soles of this boot when on their front points, and in fact, Arc'teryx acknowledges that it was designed with a less than fully rigid sole for improved performance on approaches. Climbers whose only priority is steep ice in cold weather should consider one of the super-gaiter boots.

Weight

For the most part, companies list the weight of one boot (or 1/2 of a pair) in a size 42. Many of the online sources of information on this boot, including the Arc'teryx website, list different weights. Our tester pair is size 43 and 1/3 (Arc'teryx labels their Euro sizes oddly, this is the equivalent of a 9.5 US men's), and one boot weighed in at 2 lb 2 oz (or 965g) on our freshly calibrated scale.

It is one of the heavier boots in our review. However, the other models in the same general weight range are less warm and weather resistant.

The Acrux is only a few ounces less than modern 6000m double boots. While we appreciate the slight weight advantage, our testers really noticed the difference in the overall size of the boot. When measured around the fullest part of the forefoot, the Acrux is about an inch smaller than the La Sportiva G2SM.

Weather Resistance

A dry foot is a comfortable foot. Because of the gaiter, super-gaiter boots are inherently more waterproof. Maybe it's just because Arc'teryx is based in rainy Vancouver, but for waterproofness, the Acrux can't be beaten. The only way your foot is getting wet is if water comes in over the top of this 12-inch (30cm) high boot.

The liner boot of the Acrux has a Gore-Tex membrane. The gaiter of the shell is also constructed with Gore-Tex and has a waterproof zipper. The top of the gaiter has a built-in drawcord to seal it around your legs and keep out snow. If snow coming in is a concern, we think the best plan for this boot isn't to tuck your pants into it but rather to let them drape over and keep that drawcord tight.

Warmth

This is a category where the Acrux AR shines. Many factors well beyond boot construction contribute to how warm our feet feel.

Nonetheless, our testers felt that this was one of the absolute warmest boots in our review. Insulation comes both from the removable liner boot and the inner shell. Because the gaiter traps heat, any boot with an integrated super-gaiter construction will be warmer than one without, and that's certainly the case here.

We have used this boot for six separate five-day trips over 14,000 feet (4200m) in the winter. Every time, our feet stayed warm for the whole trip, even summit day. That's because we could pull out the liner and bring it into our sleeping bag to dry each night. With any lightweight, single, or super-gaiter boot, drying the boot out each night would have meant spending lots of time cleaning all of the snow off of the exterior before bringing it into our bag. Even then there would be two rigid objects in the sleeping bag with us, which is not a comfortable proposition. The other advantage of having the liner in your sleeping bag is that in the morning, your foot isn't forced to warm up the cold boot.

Hiking

Our testers were pleasantly surprised by how comfortable this boot is for hiking. While it's certainly no cushy trail runner, it performed better than some much lighter boots. We think the slight flex in the sole helps counteract the weight of this boot when we're hiking on trails.

The sock-like fit of the inner boot kept all blisters at bay, regardless of approach length. Once again, the convenience of the velcro ankle strap let us hike with the ankle of the boot reasonably loose, but the laces snugged up.

Lacing

The lacing system of the boot is good. Traditional laces cover the forefoot and up to the ankle with no lace lock. The upper part of the boot is secured with a power strap. As mentioned, our testers really like the power strap for quick adjustments.

The inner boot has a sock-like fit and features no laces. We often got the best results by pulling this onto our foot and then putting our foot in the boot shell.

Should You Buy the Arc'teryx Acrux AR?

If you've got perpetually cold feet, check out the Arc'teryx Acrux. It is a super warm boot. A removable liner on a boot designed for altitudes less than 6000m is a unique and advantageous feature and gives this boot a level of versatility not found in comparable products. While this isn't a perfect contender for cold weather ice climbing, it does get the job done, and its other attributes make it uniquely qualified as an all-around cold-weather mountain boot.

What Other Mountaineering Boots Should You Consider?

Climbers looking for something decently warm but much lighter weight should check out the Asolo Eiger XT GV Evo or Scarpa Phantom Tech. If you want something that slays steep ice and is super durable, the affordable La Sportiva Trango Tower Extreme GTX is worth checking out.