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K2 Spyne 120 Heat Ski Boot Review

K2 Spyne 120 Heat Ski Boot Review

Posted On 23/01/2021

K2 Spyne 120 Heat Ski Boot Review: If you are an advanced skier and you are looking for high-quality ski boots that can also heat up your feet in extremely cold conditions while having your sports activities in the winter these K2 Spyne 120 Heat Ski Boots are worth to take into consideration. Now, let’s go and take a look at the features included in these high-quality heated ski boots.

Our Verdict

The K2 Spyne 120 Heat is a high performance heated ski boot for advanced and expert skiers with mid-stiff and versatile flex 120 backed up by a Y-shaped design at the back of the ski boot to enhance the power when forward lean and increase the performances in dynamic skiing.

This K2 Spyne 120 ski boot comes with heat-moldable shell and liner that is a result of cooperation between K2 and Thermic which results in incorporating the high-quality USB Rechargeable Thermic Heat Technology in order to heat and protect your feet from cold while skiing in extreme condition.

This Thermic Heat Technology, in low heat setting, will provide you entire 19 hours of heat while in the highest heat setting you will be provided about 6 hours heat which is really amazing.

This K2 Spyne 120 heat also incorporates a lot of advanced technological solutions such as LuxFitPro Liner, Energy Interlock System, Cuff Alignment, Adjustable Power Wedge, Power Cinch Strap and more; all that to improve your skiing enjoyment and experience on all types terrain regardless the temperature.

K2 Spyne 120 Heat Ski Boot Review


Features and Performances

Let’s take a look at some of the main features and performances that make this K2 Spyne 120 heat stand out from its competitors.


Flex Rating

Let me tell you right at the beginning. If you are a beginner these are not ski-boots for you, even if you have some experience you will have problems when skiing with these boots because they are too stiff which also indicates the flex number of these ski boots.

They have a flex rating of 120 and are designed for skiers who are advanced or have expert experience, skiers who prefer high speeds on different terrain in the mountains.



These K2 Spyne 120 heat ski boots feature a medium-grip sole. Intended to improve the grip between boots and skis or when walking with these boots, the sole is made so that in the center of the sole is used double thermoplastic urethane. This greatly contributes to increasing the usability of these K2 Spyne ski boots.


The Last

The last of these ski boots is 100mm. This means skiers who have an average foot width will be able to use these heated boots for skiing without any problem. They will feel comfortable even after a long time of skiing without any discomfort on their feet. In fact, the 100 Last of these boots means that they will work best for professional and advanced skiers who have wider or narrower feet than those with average feet.


LuxFitPro Liner

It is obvious that K2 Spyne 120 heat ski boots will come with the LuxFitPro Liner that offers a combination of performance and perfect fit of traditional PVC foam.

These moldable liners can be perfectly molded to the shape of your feet which they will perfectly fit with the interior of your ski boots. When the liners are molded in this way, they will be able to precisely transfer the energy and power from the ski boots to the skis.

The LuxFitPro liner comes with Asymmetric Tongues which also are moldable in order to reduce shin bang so that you will get better comfort and smooth, precise flex initiation that will enhance the performances when you skiing.

With this K2 Spyne 120, you will also get a Power Collar and Power Wedge that will give you a varying forward lean and also support the upper cuff that will enable you successfully skiing in challenging conditions.


Energy Interlock System

The K2 Spyne 120 heat ski boot features with an Energy Interlock System. Actually, this is a rivet-free technology that connects the cuff and shell of the boot. This is a fundamental technology in designing ski boots and it is also responsible for the control of the power and durability of the skis when you ski on different terrains regardless of your skiing style.

In fact, the way this Energy Interlocking System works is when the ski boots are flexing forward, then the interlock system stretches to deliver extra energy that reduces stress on the material of the boots and at the same time provides you with a natural, more balanced and efficient flex while skiing. So you can enjoy more dynamic skiing on different terrains in different conditions.


The Cuff Alignment

For people who have problems aligning their knees/legs, the K2 Spyne 120 heat ski boots offer an effective solution by implementing one Cuff Alignment on each side of the boot in the ankle area.

The Cuff Alignment, or so-called lateral tilt of the cuff, will allow skiers to tune the geometry of ski boots depending on the specific morphology of the legs.

The skier who is knock-kneed should adjust the cuff tilt to the inside so-called negative canting and if the skier is bow-legged he should adjust the cuff tilt to the outside so-called positive canting. The K2 Spyne 120 heat ski boot allows you to do cuff adjustment for +/- 2˚.

With this canting adjustment, the skier gets a more natural stance on his skis, and he can easily engage or disengage from the ski edges.


The Power Cinch Strap

The K2 Spyne 120 heat ski boot features with 40mm PowerCinch Strap. This belt is designed to provide a very snug fit of your leg along with the rear spine of the ski boot shaft. Actually, with the PowerCinch Strap, you will reduce the space between the calf muscle of your leg and the rear spine of the ski boot.

K2 Spyne 120 Power Cinch Strap 


Adjustable Power Wedge

Also, K2 Spyne 120 heat ski boots come with a power wedge spoiler. This spoiler is designed to accommodate skiers with different calf shapes by adjusting the forward lean angle. The power wedge in these ski boots allows you to increase the forward lean angle from 12 to 14 degrees.


Replaceable GripWalk Outsoles with Padded Mid-Grip

A great feature of these K2 Spyne 120 heat ski boots is that their GripWalk outsoles are replaceable. This is another of the many positive features of these boots. If the soles in these ski boots are worn out you will simply be able to replace them with new ones.

This is very important as you do not need to replace your ski boots with new ones if the existing soles in these ski boots are damaged. Simply put, these K2 Spyne 120 heat ski boots feature saves you money in addition to skiing pleasure.

Also, these GripWalk soles allow you a better grip and additional comfort whether you are walking or standing, and at the same time, there is no compromising of the power transmission and release function between the ski boot and the binding during skiing.


Micro-Adjustable Buckles

Like most high-quality ski boots, these feature durable high-quality aluminum buckles. In total there are 4 aluminum micro buckles whose main task is to allow you to easily adjust these ski boots to the size of your feet.


Easy to Pull Tongue

There is one small but very useful feature in these K2 Spyne 120 heat ski boots that is the ability to pull the tongue. The top of the tongue on these ski boots has a fabric loop that allows you to easily pull the tongue forward and to the side, so you can easily fit your foot into the ski boot.


PowerFuse SpYne Technology

One feature that I really like about these K2 Spyne 120 heat ski boots is Powerfuse Spyne Technology. Actually, this is a Y shaped rear design, that gives the Energy Interlock system extra strength and power. Also, this PowerFuse SpYne technology enhances the efficiency and stiffness of the rear and front flexes, thus improving the performance and responsiveness when you ski on different types of terrain.

K2 Spyne 120 PowerFuse SpYne Design 


USB Rechargeable Thermic Heat Technology

One of the main and perhaps the main reason why we buy these ski boots is the built-in heating system. These boots have an integrated heating system from the well-known brand Thermic.

The heating system in these boots consists of high-quality thermal heaters that are also connected to a high-quality lithium-ion battery with high durability that enables thermal heaters to heat your feet for a fantastic 19 hours continuously without interruption.

The lithium-ion batteries can be recharged via a micro USB plug that is embedded in the boots’ foam liner. You can easily adjust the temperature of your feet with the flat, large and easily visible buttons located on the upper side of the ski boots. Thermal heaters cover the entire shell area in the area of ​​your feet without creating unnecessary, uncomfortable foot pressure.

I think this is one of the most desirable features that skiers want to have in their ski boots. Thanks to this heating system you will be able to fully dedicate and enjoy skiing regardless of the outside temperature.



If you are an expert skier and you love dynamic skiing but you have a problem with cold feet and you are expecting extreme conditions when skiing then you really need to consider top performance heated ski boots like K2 Spyne 120 Heat Ski boot.

These are one of the best combo heated ski boots that offer great comfort, stiffness, an incredible balance of power, and precise control when skiing and what is more important at the same time they can provide optimum heating to your feet. But you need to know that all those high performances come with a really high price.

The only disadvantage of these heated ski boots is their high price. I really hope that my K2 Spyne 120 Heat Ski Boot review gave you enough info about this top performance product.

For those who already have ski boots without a heating system, I would strongly suggest to don’t invest in new heated ski boots that have an integrated heating system. There is another alternative solution to heat your feet in your ski boots while skiing in winter, which is buying a ski boot heater.

You can take a look at our top selection of the best ski boot heaters that exist today. By buying a ski boot heater instead of new heated ski boots, you will save a lot of money.

Any of the ski boot heaters can be easily installed inside your current ski boots by yourself or the installation can be done at your local ski retailer. As well, I recommend you to read our full review for one of the most popular ski boot heater Hotronic S4 boot heater here.

Written by Miki Ristovski

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