Mammut Sapuen High GTX Boots – My Review

The Mammut Sapuen High GTX Boots are very advanced with their Flextron II steel sheet Vibram sole, and memory foam padding, and they offer an excellent ankle support.

Key features & benefits

What is in the name

The title above shows the official name of the boots, but the word ‘High’ in the name is not really appropriate. In fact, these are mid-cut boots.

When I measure the height from the outside, it gives 6.89 inches (17.5 cm). Compare this with my Lowa Renegade boots with their 7.3 inches (18.5 cm) height, and they are known as mid-cut boots. 

The meaning of the letters GTX should be obvious, this is about their waterproof GORE-TEX membrane that is supposed to make the boots waterproof. But is this really so? You will find out below.

One interesting detail is ‘Elastic GORE-TEX Tongue Construction’ mentioned in specifications. The picture below shows what they mean, there is a stretch piece that connect the tongue with the upper shaft, and yet it does not allow water to pass.

The lacing is what they describe as ‘Standard lacing’, and this implies three pairs of loops and three pairs of hooks. The picture shows the details. 

Note that the first hook (the third from the top) is of a locking type. In practical terms, this means that you can independently adjust (tighten) the lower part where you see those three loops, and the upper part with the two remaining hooks. I have a good experience with such a design from my previous Salomon boots.

Materials and construction

There is a lot of technical details here, the boots are a marvelous piece of engineering. To start from the bottom, the soles are Vibram XS TREK.

So what is Vibram XS TREK? On their site is described as a technical compound for great overall outdoor and multisport performance, with principal characteristics being flexibility and wet traction.

But there is also the term Vibram Flextron II. From their description it is about ‘support of the natural rolling movement of the foot for a more efficient use of energy’. 

After watching their videos on YouTube, I realize that this is related to a steel shank on the all length of the sole, it is more or less of the size of the inner sole. You can see a part of it in the picture below, observe the orange element deep inside of the sole, this is it:

So this is a steel piece, and it is added for torsional stability of the feet, for flexibility, and also to protect the feet from the ground. The central area of the steel plate is flat, but the two ends are corrugated.

In the video below you should see more, but note this is Flextron, while these Sapuen High GTX boots have Flextron II, so most likely this is an improved variant.

But I must confess, they lost me with the statement I found in their description: ‘sole design that supports self-cleaning’!?

The picture below shows the boots after my first walk with them in the woods. Now you may know why my wife complains every time when I get back from such walks.

The point is, if you walk in the mud, you will bring it home, this is guaranteed, so I do not think that these great boots need such a useless statement.

But let’s move on. The upper and inner is again with terminology that is somewhat hard to understand; Georganic 3D technology, and a 3D Memo Foam.

In reality, the padding feels quite hard, definitely less soft than in any other boots I used in the recent years, and it is also not very thick. But it is supposed to adjust to your feet contours.

However, there is more here, the Achilles area is with a deep U-shaped cut to allow movement of the leg, you can see this in the picture below. This is a great detail, I could feel its positive impact immediately when I started walking in these boots.

And here, they have also added a separate but fixed piece of cushion, a 3D Memo Foam pad shown in the picture:

Note that this Achilles area is not very deep, only around 9 cm from the inner sole to the top. The mentioned pad is higher, so the total inner height with this cushion is around 12 cm.

Now, would you describe this boot as ‘high’? Indeed, these are mid-cut boots as I mentioned above. I really love the orange inner color:

The upper is a combination of several materials. Most of it is made of what looks like a suede leather. There are large rubber overlays combined with some synthetic material, plus a knitted upper on the top front and in the laces area introduced to improve breathability.

In simple terms, everything is anatomically shaped and it all looks advanced and well-made, craftsmanship here is at the highest level.

Flex index A6. What is this?

In the specifications of these boots you will see this term mentioned. So, what is flex rating on boots? More or less this is about rigidity and responsiveness. For hiking boots and shoes of this A type, Mammut has its own flex rating in the range A4-A9, where A4 means a soft flex and high cushioning.

So in these Mammut Sapuen High GTX boots you are right in the middle. Now you can perhaps understand better the sentence on Amazon where they describe them as ‘the right choice on all kinds of terrain’.

Note again that this is their own rating. From what you can find online, there are no clear standards in this industry, so different brands use different ratings.

PFC-free DWR, what is the meaning?

This is about perfluorinated compounds (PFCs) that are practically non-biodegradable, some bad stuff indeed. They write that Mammut is committed to replacing such non-biodegradable fabric treatments with more sustainable high-performance alternatives. 

Are Mammut Sapuen High GTX Boots waterproof?

I tested the boots in my usual way, by simply putting them in the water as shown in the picture below. This was after a number of walks as you realize from the mud in the water, that came stuck in the lugs.

I did this with each of the boots separately and kept them in water for 5 minutes, they were submerged up to the second hook.

So the front with the mentioned fabric area, and a big part of tongue were submerged. I was curious about the stretch piece that connects the tongue to the shaft. It was in water, but there were no leaks inside. My conclusion was that the boots were indeed waterproof. 

However, two weeks later, see what I had after getting back from a one-hour walk in the rain:

As you can see, my socks were wet in the area with the mentioned stretch section of the tongue. But observe also the wet areas on the front. 

Weight

The boots weigh 2.566 pounds (1164 grams) per pair (or 582 grams per boot), and this is my own measurement for the size UK 8.5 (US 9.5, or EU 42 2/3). Note that the official weight is 530 grams per boot, but it is not clear which size this is for.

Now, is this heavy or light? The boots feel very light when you keep them in hands. But indeed the only way to understand the weight is to compare with some other top brands in this industry.

Luckily, I have used them many, so my Salomon Men’s Quest Prime GTX weigh 1140 grams per pair. On the other hand, my previous Lowa Renegade boots measured 1130 grams.

As you realize, these Mammut Sapuen High GTX boots are in the same weight group, and I would describe them as lightweight hiking boots.

Size & comfort

Regarding the size, I am using a pair that is a bit too long for me, but a smaller size would be too narrow. So in my view, the boots run narrow in the mid-foot area, bear this in mind if you have wide feet.

Out-of-the-box comfort?

I have seen such statements before traying the boots, and I was quite skeptical. Namely, these boots feel hard, and the padding is not really thick.

After my first 10 walks of 3-4 kilometers each, I did not feel any serious pressure spots. I have been using various types of socks, some thick and some thin, and I was pleasantly surprised.

But…

Who are these Sapuen High GTX Boots for

Regarding the best use, wait to see this: on Amazon these boots are under the name Mammut Men’s Jogging Trail Running Shoe! Clearly, somebody has made a serious mistake there. 

This aside, on their site you will find them described as boots for hiking and mountains, and this is indeed so. These boots offer an excellent ankle support, and the bottom is a quality Vibram design with optimal feet protection.

You have seen the details about their sole, so there is lots of technology there, and this makes the boots suitable for hikers and backpackers on a variety of terrains and for day and multi-day tours.

But wait for a couple of months, I plan to take them to the Dolomites, and I shall have a chance to test them properly on various tours in a high Alpine environment.

Regarding the price, these boots compare well with some other top brands’ boots mentioned above. No surprise here, the quality is at the highest level, and this comes at a price. 

However, if you are on a budget, you can check something much cheaper, the NORTIV 8 Men’s Ankle High Waterproof Hiking Boots. But their official name given here is misleading, they are not waterproof.

Please see more in my video review:

Addition:

Here is my report 10 months later, after testing these boots on many tours in the Alps:

Final thoughts & rating

Below you can see how I rate the boots against my usual rating criteria so that you can easily compare it with other items of this type:

Mammut Sapuen High GTX Boots

9.2

Weight

8.8/10

Comfort

9.5/10

Features

9.0/10

Design & Style

9.6/10

Pros

• Advanced designed.
• High level craftsmanship.
• Optimal ankle support.
• Lightweight.

Cons

• Expensive.
• Not waterproof.

BEST PLACEs TO BUY

Mammut

Amazon-US

Amazon-UK

Go Outdoors

For more options, please check under the category Men’s Footwear. 

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