The La Sportiva G5 does everything we need a mountain boot to do. They climb really well, and keeps your feet surprisingly warm, given how light they are. Everything that is, except for keeping your feet dry when confronted with liquid water. Scroll down to learn more.
Performance Comparison
The G5 provides a rigid platform for placing screw from.
Weight
This boot was pleasingly light, weighing in at 1lb 15.2oz (885g) for our tester size, 43. It weighs essentially the same as the Scarpa Phantom Guide. The inner boot is low cut, which certainly helps, but it seems like it's mostly space-age materials that keep this boot svelte. Sportiva somehow managed to keep the weight down while still providing a beefy outsole. Take note, if you spend a lot of time approaching on rocky terrain.
The G5 is a bit lighter than it's predecessor, the Batura (right).
The G5 clocks in about 6oz lighter per boot than the La Sportiva Nepal Cube. That's 12oz for the pair, which is about equivalent to a #5 Camalot C4! The only boots that are lighter than the G5 are the lightweight single boots, which are less warm and less water resistant.
Warmth
This is a warm boot, tied for second in warmth with the Phantom Guide. We think that the only way climbers are going to get a warmer boot is with a double boot, like the Arc'teryx Acrux AR or even bigger 6000-meter boots.
Side-by-side testing the G5 and the Phantom Guide.
All the fancy materials in the upper help with that, but certainly the thick mid and outsole contribute when we're standing still, in the snow, with crampons strapped to our feet.
Water Resistance
This is a problem area for this boot. We'll start with the good stuff. The gaiter does an excellent job keeping out all kinds of snow in all kinds of situations. The boot is made of waterproof materials, including Gore-Tex.
Taking on water in our tub test.
Now the bad. The construction of the boot is not water resistant. The gaiter is closed with a standard (not waterproof) zipper that's covered by a velcro flap. The inner boot is two overlapping layers of fabric that aren't connected by a gusset or bellows. What this means is that when we stepped into our plastic tub filled with 6 inches of water to test water resistance, the G5's immediately began taking on water. After 5 minutes we dumped out about a 1/2 cup (4oz) of water from the boot, and the entire inside was soaked. We performed the test wearing a different boot on each foot, so we immediately grabbed the other G5 and stepped back into the bin; same result.
Now, it's a rare mountaineering situation that finds us standing in six inches of liquid water for 5 minutes, but we did learn that the "water line" on these boots is just over 3 inches. That's about half that of the next lowest, the La Sportiva Trango Tower Extreme GTX.
Climbing
Some boots in our test are ice climbing machines, others are clearly designed with steep mixed terrain in mind. The G5 presented the most well-rounded climbing performance in our test. Our testers were happy to have this boot on their feet whenever they tied into the rope, so it's the highest scoring boot in the climbing metric. The rigid sole and power strap were a boon on steep ice.
We really liked the power strap for quickly fine-tuning the fit.
On mixed ground and pure rock, climbers can loosen the power strap and enjoy a good range of motion in the ankle. The deep dive of the cuff around our Achilles tendon helped with this also. The La Sportiva Nepal Cube GTX is the best boot for steep ice in our test. The Asolo Eiger GV is the best for mixed climbing and dry tooling.
Lacing
We didn't do any timed drills (though that could make for funny video…) but this is one of the fastest boots to put on or adjust in our test. At the car, slide your foot in, turn the Boa knob till the forefoot is snug, and pull the velcro strap until it's tight but not too tight, zip the gaiter and go. At the base of your route, or when the climbing gets serious, unzip the gaiter, tighten the Boa a few clicks, cinch up the velcro, and send.
The Boa dial and laces.
A note about the Boa; a number of climbers who had experience with early versions of this system over a decade ago were dubious about its durability. Our lead tester has logged over 60 days in his La Sportiva G2SM's, which have 2 Boa laces per boot, with no issues. Our testing team put slightly fewer days on our pair of G5's but also had no problems, despite cranking hard on the knob. It's certainly a more complicated system than old-fashioned laces, but we appreciated the ease of operation with gloves and the ability to make quick micro-adjustments.
Hiking
The G5 hikes pretty well for a mountain boot. We found ourselves often leaving the power strap undone for the hike in which, in combination with the deep Achilles cut-out, let us walk with a fairly comfortable gait on dry hiking trails and snow-covered talus.
Best Applications
Though this boot is light enough to take on summer missions, it was clearly built to climb in the cold. If you're a cold-footed mountain guide, wear it to stand in the snow belaying all day in Ouray or Bozeman. Take it on the coldest of your winter day-trips in the lower 48 and Canada. Or if you're Colin Haley, wear it on the first solo of the Infinite Spur on Mount Foraker! Whatever you do, don't bring it out on very wet days.
This boot had great all-around climbing performance.
Value
At $750 MSRP this is one of the more expensive boots in our test. For some mountaineers, the water issues and concerns about the durability of the Boa system will be a deal breaker. We think this boot is an okay, but not great value.
Conclusion
With its fancy materials and design, this boot is like a message from the future of what mountain boots will be. It's light, it's warm, and it's quick to put on and adjust. One thing it isn't, however, is water resistant. For some climbers that won't be a deal breaker. If this boot fits your foot and you think you won't be fording any streams or jumping in any puddles this could be the boot for you. Our testers found that this boot felt wider/higher volume in the forefoot than the Scarpa Phantom Tech.
Ice and snow can't get into this boot, but keep it away from liquid water.
