First Look: Featherweight ‘Cube GTX’ Mountain Boot

Fast and light trickled its way down to the soles of mountaineers last year, yielding several boots that tipped the scales less than ever.

La Sportiva’s Trango Cube GTX is one of these super-light boots. It comes with a splash of rainbow colors and about 1.5 pounds of weight (per boot).

The latest incarnation of the Trango line, the Cube is billed as La Sportiva’s most technically advanced offering, cutting the superfluous without cutting corners. Seamless construction, removable elements, and synthetic materials abound. We wanted to know if all this stripped-down goodness could still deliver the comfort we yearn after hours on steep slopes.

In preparation for some springtime fun, I’ve been kicking the Trango Cube up and down the local ski hill. Here’s a look at what I found.

The Gear: La Sportiva Trango Cube GTX

Available: Since 2014

Price: $375

Made in: Italy

Where to test It: Non-technical mountaineering routes, cross-country mountain hiking.

The Basics: The Trango Cube GTX is La Sportiva’s fourth installation in the Trango lineage (behind the Alp, the EVO and the EVO Extreme). At 23.5oz. (per boot, sample size), it’s also the lightest in the family.

To get the pair below the 3lb. mark, La Sportiva borrowed a few tricks from the garment industry, like stripping traditional sewn-together seams in lieu of welded technology and reducing portions of synthetic materials and thermoplastics.

The Cube’s synthetic waterproof upper is paired with a GORE-TEX liner and rides over a lightweight Vibram base. The vamp of the boot is wrapped with a rubber rand to rebuff shards of granite from cutting up the boot as you kick your way to the summit.

Important Specs: The Cube cut some volume off the standard Trango by using a thinner mounting layer that binds the outsole and midsole. This reduces the amount of rubber on the road and gives the Cube a racy low-riding chassis at less weight. The proprietary Vibram “One” sole is a combination of compression-resistant polyurethane paired with lighter, more forgiving EVA inserts in the footbed and heel.

Replacing leather is a thermoplastic “exoskeleton” that wraps the throat of the boot, adding support and protection while still enabling the boot’s flexibility.

For comfort, the Cube incorporates a plush, spongy internal mesh padding and stretchy tongue that minimizes the lining from folding. And if you find that you need more volume for a winter sock, or simply can’t spare the extra grams, the tongue can be easily removed to strip the Cube down to fightin’ weight.

All these weight reductions make the boot a pliable walker for long days on the lam. Is it at the risk of a shorter shelf life? Only time will tell.

Tying the knot: Instead of traditional riveted alloy hooks and eyelets, the Cube’s Thermoplastic Urethane hooks are integrated with the exoskeleton. This cuts a few additional grams and gives the boot a cleaner internal lining.

The hooks self-lock with each bite of lace, and a loop of webbing on either side of the ankles keep the otherwise unwieldy length of cord in check. Most importantly, the fit didn’t budge after hours climbing up and down the hills.

Base Instincts: I wore the Cubes while thrashing up stubborn resistant alpine scrub and plunging down a wreckage of tree fall and creek beds. They kicked steps when I needed to be assertive but were stable underfoot while carefully descend to the valley floor.

Pros: Lightweight—perhaps the lightest mountaineering boot on the market. The unique seamless design provides out-of-the-box comfort.

Cons: Although La Sportiva positions the Cube as a ‘technical mixed climbing and ice climbing” boot, I’d be hard-pressed to support this statement.

• It lacks the requisite front welt to take technical front-bail style step-in crampons.
• The liner is thin … perhaps too thin to keep feet warm while belaying pitches on ice.
• They lack a full shank (running a half TPU shank) and hence lack the support for extended time on vertical ice

But the heel welt readily slips into a traditional strap or hybrid design crampons, and the boots are plenty warm while on the move.

For a comparable boot with a toe-welt, climbers will want to look at Scarpa’s Rebel Pro GTX. Though this boot will set you back $125 more than the Cube.

Parting Thoughts: Earlier in the season I schlepped heavy loads in full-grain leather boots so burly that I simply couldn’t break them in…they broke me in. After 20 years, these old boots still cause blisters at the start of a season.

The Trango Cube sits nearly at the opposite side of the spectrum, with perhaps more in common with a traditional backpacking boot than a mountaineering boot. I donned the Cube’s out of the box and had zero issues with hot spots. Switching from my heavier boot mid training cycle felt almost like cheating my training.

The boots felt so light, in fact, that at the end of one hill session, I picked up the pace and ran the last mile out to the truck in the Cubes – which is something I could never do in my plastic or leather boots.

For summer mountain routes on the likes of Rainier or routes in the Canadian Rockies that require long hauls into the wilds, I may never look back to my leather-lugged sole mates.