UKC Chief Editor Jack Geldard tests out the super light Nepal Cubes from La Sportiva - but are they as good as his tried and tested Nepal Extremes? And are they warm enough and tough enough for hard mountain abuse?
I've got some Nepal Extremes, and I've had them for about 10 years now. They've been to four different continents, and climbed countless routes. Yep they are getting pretty beaten up, but with a resole I'm hoping they might do a few more seasons yet.
Question: Now I have a pair of Nepal Cubes will I still need to resole the old faithfuls, or will they be put on the UKC for sale forums at a knock down price?
Answer: I'm not sure.
At first glance the new Nepal Cube looks like a newer, sexier version of the Nepal Extreme, and in many ways it is. They're both skinned in the same striking yellow 3mm Hydro-Perwanger leather that has stood the test of time for hundreds of climbers. They have the classic big black rand around the whole boot and they have the stand out red midsole and quality Vibram sole unit. But there are some key differences.
Nepal Cube: 1780gm per pair (size 42)
Nepal Extreme 2250gm per pair (size 42) and I'm pretty sure the old Nepal Tops were a bit heavier again.
That is a weight saving of 470g on your pair of boots. If anyone out there does any ski racing you will know just how significant saving weight on the foot area is in terms of energy output for moving around the mountains. It's massive. I have heard that having weight on your feet uses 6 times more energy than the same weight in your rucksack, meaning the saving from these boots equates to shaving 2820g out of your bag. That's like carrying an extra rope, or in my case that's like carrying two extra bottles of wine.
If you pair these boots up with a lightweight crampon like the Petzl Dart, then you will feel a huge difference when climbing technical terrain such as hard Scottish winter climbing, and if you use them for more classic alpinism then you won't get as knackered when slogging up long snow ridges.
It's hard to scientifically measure the warmth of boots when out on the mountain. Some days are colder than others, some days you've had less to eat, some days you're just bloody tired.
But after quite a few big routes in the Cubes, I have to say that in my opinion they are not quite as warm as my old Nepal Extremes.
Much of the warmth in boots like this comes from the insulation. The Cubes have an insulated Gore-Tex liner, which is very slim, but does an okay job at keeping the foot warm, and a great job of keeping it dry. I've tested the Cubes down to -5, which isn't super cold, but is a reasonable test of temperatures for Scottish climbing and summer alpinism. They were warm enough at -5, but I wouldn't want to push too much lower, certainly not at high altitude.
The liners breathed well when the sun did come out over the alps, and for those late afternoon slogs in the full sun and wet snow the boots were great. They felt light, breathable and the fitted ankle cuff section kept out snow well.
I'd say that whereas with the Nepal Extremes you can push it a little and use them in alpine winter on shorter routes or when the temperatures haven't dropped super low, I'd be too worried about my feet to go for a big north face in winter in the Cubes.
I wouldn't have any worries about summer alpinism and Scottish winter, but if you are a real sufferer of cold feet in general, you might want to get a beefier boot.
So where have they saved the weight? I'm guessing most of it has been shaved off the insole.
These are B3 rated boots, they are fully stiffened mountaineering boots. The insole is made from a honeycomb of carbon, giving them the rigidity they need, but keeping weight right down.
But one of the jobs of the insole is to insulate from the cold ground or snow underfoot. I've read that the Cubes are warmer than the Evos (the sort of in-between version of the Extremes and Cubes - check out the Evos here), and part of the reason they are warmer is because of this carbon insole, but although I don't have any Evos, I can say that I haven't found them as warm as my Extremes.
The first thing I noticed about these boots was the build quality. It is really good. Whilst La Sportiva have shaved off loads of weight with these boots, they haven't skimped on the toughness. The stitching and glueing is all top notch. They are showing virtually no sign of wear at all even after several multi-hour alpine approaches and quite a few pitches of granite scrambling.
The boots feature a removable tongue so you can tweak the fit, and adjusting the tongue height by relatively small increments really does make a difference to the volume.
The fit is very classic La Sportiva - and almost identical to my Extremes. Quite a low volume heel fitting, with excellent cupping of the heel, enough width in the toe box and an all round snug and good fit for me (long, low volume feet).
The ankle cuff is a kind of stretchy sock / gaiter affair which is comfortable and keeps snow out pretty well.
The boots go on and off easily, the eyelets are high quality and the sole is a rugged Vibram unit featuring La Sportiva's "Impact Brake System".
All in all they are great boots and are built to last.
I haven't has any issues fitting my crampons to them, and I have a few models from Black Diamond, DMM and Grivel.
Bombproof, lightweight mountain boots. Take a variety of crampons, with a great design.
A lot of weight has been saved over previous similar boots, but in my opinion they aren't quite as warm.
Great for harder Scottish climbs and alpine mixed. Not warm enough for big routes in the coldest parts of the alpine winter.
Overall they are a fantastic addition to the La Sportiva mountain boot range.
But Will I Keep My Nepal Extremes? I think I will. But I'll use the Cubes for all my alpine summer climbing.
Nepal Cube, as the name suggests, is a new starting point for defining technical mountaineering boots thanks to the exceptional lightweight and thermal properties (a mere 1780g per pair).
These features are achieved from the reduced weight of the sole/midsole using a Carbon Tech honeycomb, a thermal footbed and lightweight mini steel parts. The Gore-Tex Insulated Comfort lining contributes to the overall comfort of the boot, guaranteeing breathability and water resistance. EZ OUT technology for the tongue allows more precise regulation of the fit and encourages the elimination of sweat via a mesh fabric which draws humidity to the surface. The 3D Flex System provides comfort during walking and support for the ankle on steep terrain. The Vibram sole with Impact Brake System absorbs negative ground impact, while the graded lugs promote traction and keep feet in check on downhill terrain. Nepal Cube: the origin of a new species.+ Reduced weight mini steel parts reduce the overall weight of the boot.
+ 3D Flex System promotes ease of walk and supports the ankle on steep ground.
+ All-round rubber rand protects against knocks and abrasion.
+ EZ Out removeable tongue allows a more precise regulation of the fit and helps to eliminate sweat via a mess fabric which draws humidity to the outside of the boot.
3+ mm Hydro Perwanger Leather waterproof.
Insulated Comfort Gore-Tex.
Carbon Tech honeycomb isolation.
2mm Polyurethane graded for crampon attachment.
Re soleable Vibram with Impact Brake System, fully crampon compatible.
41 – 47 (including half sizes)
1780 g (pair, size 42)
MORE INFORMATION: La Sportiva Website