The La Sportiva Nucleo is a burly model made for variable conditions and long days on rugged trails. The boots are substantial with their leather construction and solid soles. Though they are higher than most boots regarding ankle shaft height, they still feel relatively light on foot. The Nucleo's are a modern adaptation of the classic leather hiking boot of day's past, and provide the same comfort and protection as this contender did, while having a light feel and modern design.
The Nucleo is a polarizing boot; depending on your foot shape, you will either love them or hate them. For people with narrower feet, the La Sportiva Nucleo were incredibly comfortable. They provide arch support and have a well-shaped heel cup that keeps the foot locked in, but comfortably so. The boot's design is such that the upper wraps the midsole which stabilizes the foot and makes the boot feel snug and comfortable. Unfortunately, all this shaping makes for a relatively stiff boot if your foot is wide, and so this variability gives the Nucleo a lower overall score in this metric.
For a narrow foot, this model is incredibly comfortable. Unfortunately for those with a wider toe box, the Nucleos don't provide much wiggle room width-wise.
This model is designed specifically with support in mind. The boots really feel good when they are on like your foot is being supported and held in place. This is partially due to their nubuck leather uppers that mold nicely to the foot after just a few days on the trail. Both the heel and the support underfoot are substantial, features that keep the foot held in place, while still allowing for flex and movement with your stride. The boots provide ample ankle support due to their extra tall heel height. This is important if you are prone to rolling your ankles.
If you're looking for a boot that will provide tons of support in both the ankle and underfoot, the Nucleo does the job.
Regarding weight, the Sportiva Nucleo's are on the upper end of the spectrum. The boots weigh just over 2 pounds (2.03 pounds, to be exact!), which means they are one of three boots in this review that weigh over two pounds. The support provided by the ankle height of the Nucleo, as well as their leather construction, are what make up the bulk of the weight of this boot. These features are also what makes the boot so appealing, making the boots' weight is less of an issue.
Made with a sticky Vibram sole, the Nucleo did not disappoint when it came to traction. La Sportiva is known for having sticky rubber as a part of their products, and the Nucleo's are no exception. The Impact Break System, paired with the Vibram Nano rubber outsoles, keep traction with ease, especially on the downhill. We wore these boots on the slippery, polished granite trails of Yosemite Valley's most popular hikes, and found that the Nucleo's were able to stick to most anything we stepped on.
The Nucleo performs well in this metric, keeping our feet dry, even after being partially submerged in water. The nubuck leather uppers provide maximum protection from the elements, while the Gore-Tex Surround membranes allow for breathability. If there was one complaint we did have regarding water resistance, it is that the boots are a bit too hot to wear in warm conditions. Their lack of mesh and combination of Gore-Tex and leather made for a fairly warm combination for our feet.
The Impact Break System and Vibram soles provide great traction, even on wet, slippery rocks.
Just as these boots are incredibly water-resistant, they are also very durable. La Sportiva certainly seems to know how to make a boot that lasts, and the Nucleo is no exception. The nubuck leather that makes up most of the boot's uppers is durable, and the seams between the leather, the Gore-Tex membranes, and the soles showed no signs of weakness during our testing period.
The Nucleos are great for cold, wet conditions, where their water resistance and substantial leather uppers can really come in handy.
With a hefty price tag, the Nucleos are a financial investment. Like most other boots in this price range, the Nucleos are a high-quality piece of gear. All of these boots that are at the upper end of the price range are a step above the rest regarding durability, construction, and overall support.
Overall, the La Sportiva Nucleos is a great boot. They are durable, water-resistant, and supportive. The high ankle shaft height provides protection and stability, but the boots remain flexible enough to allow for lots of foot movement while walking. This gives the boots an overall light feel, even though they are on the heavier side on the scale. In terms of comfort, the boots are super comfortable, if they fit your feet properly, they are fairly specific in their design, and if your foot doesn't fit this mold the boots will be uncomfortable. This, as well as their lack of breathability, are the Nucleos two downsides. Otherwise, these are a great boot for the price and will last a long time on the trail.