New Balance Fresh Foam Hierro V6

The American brand New Balance, with more than 100 years of life behind it, has an important novelty for mountain runners in 2021. They are one of their most successful trail running shoes and one of the most successful among the fans of this sport. We are talking about the Hierro, a shoe with Fresh Foam technology as the cornerstone that in this sixth version receives numerous changes. Which ones? We explain them to you.

A new upper

If something has improved in this version of the New Balance Fresh Foam Hierro V6 it is the aesthetics. And in particular the upper, which has been modernised, improving the more conventional and even a bit old-fashioned look of yesteryear.

If we consider the previous version, the mesh is more resistant, more reinforced in key points where mountain runners need. From the toe to the back has been improved to offer a better fit to the feet, adapting perfectly to the shape thanks to the mesh type bootie with which we get a great support. This also makes it a more rigid shoe, but not more uncomfortable. We refer to a structural rigidity, since the Tpu thread reinforcements are located in the outermost part of the mesh that does not come into contact with our foot, making the shoe more resistant to breakage and tears.

As we have pointed out, it is a bootie type mesh, well closed and single layer that provides great comfort along with great ventilation. And this ventilation is helped by the holes in the upper of the shoe. Although at first glance we can see that it has less than in the V5, they do perform well their function of perspiration although it does not hinder the entry of water, which will be difficult to evacuate.

The tongue is attached to the mesh by a pair of semi-elastic threads that avoid the typical holes through which a stone or dust can enter, improving comfort.

In the toe cap we find the Toe Protect, a type of thermo-sealed reinforcement that prevents the mesh from breaking and our foot does not suffer from the impact of rocks, stones, roots or other objects that we can hit in the mountains.

Finally, the heel. The inner part is very well padded – even more than in the Hierro V5- which offers a high level of comfort, minimising the movement of our heel and avoiding annoying chafing after many kilometres. The outer part has a rigid reinforcement that is higher, but not annoying along with the icing on the cake: a built-in puller to better fit the shoe.

The key is in the midsole

If the New Balance Fresh Foam Hierro V6 stand out for anything, it’s for their midsole. And this is thanks to the Fresh Foam. Created in 2014 as a new formulation of an EVA foam, it has had a long trajectory until today. And it has also received numerous changes until achieving the Fresh Foam X, the foam of the latest models of the American firm. This Fresh Foam X is a one-piece. No cutting or trimming. No trick or gimmick. According to the brand itself, it has been a leap in quality in terms of feel and reactivity.

If we compare it in composition and geometry with the conventional Fresh Foam, there are certain differences that have allowed us to obtain a greater cushioning capacity as well as a better reactivity. And all this while reducing the weight of the foam.

The characteristic hexagonal shape of the Fresh Foam cells now has an asymmetrical and irregular shape similar to the microscopic foam structure. It is composed of concave and convex areas that allow better compression, thus increasing the feeling of cushioning.

A wide base shoe, a bit more than what we personally like, but thanks to this we get a better stability and a more uniform distribution of the forces when impacting against the ground. It also has a drop of 8mm – 32mm heel and 24mm forefoot- which makes it a handicap for minimalist runners.

A more dynamic, agile and easy transition is the result of the combination of the different factors that make up the midsole. A shoe with which it will not be difficult to accumulate kilometres due to its comfort, cushioning, shock absorption and reactivity. It does not require great technique to go about comfortable with them because the foam does its job very well.


If something works, why change it? That’s exactly what New Balance has done in the outsole of the Hierro V6. Continuing with the Vibram brand to offer the best grip and traction in any condition and any type of terrain we face. The Vibram Megagrip outsole is synonymous with good results.

It has a sole with different lugs, large, with little space between them and with a hexagonal shape in most of them. We say that the lugs have different shapes and dimensions because if we look at the front part, they are smaller in order to get wider lugs in the central area and in the heel area. These are just the landing and take-off zones that help us to promote traction. In addition, they have small indentations that facilitate traction in rocky areas or with elements with which we can lose grip. This arrangement and the large number of lugs means that the contact surface is more extensive, avoiding increased wear.

As a result, you get a rather soft, yet very durable and abrasion resistant outsole, with a very similar feeling to riding with an asphalt shoe on a firm and stable surface, on wide roads and tracks.

The base of the sole is not completely flat and even less so if we look at the front part. It has a honeycomb-like structure that makes it non-uniform and prevents the mud from sticking too much.

Both the forefoot and the heel have rough lugs, with a certain relief in its design with which we will gain more grip on rock and somewhat wet surfaces. On the contrary and in order not to generate more friction than necessary, the lugs in the central part are smooth as well as smaller and with irregular shapes.

Finally, at the rear it includes a kind of spoiler that protrudes from the sole. An element with which you get more grip and stability on descents thanks to a larger contact surface, but be careful if you land on your heels because you’ll wear it out before you know it while riding on the flat. But it also has another function: to make the heel squarer for better support, thus avoiding ankle sprains due to a bad impact against the ground.

Putting in the miles

When we weighed them on the scales we were amazed! The 313 grams in size 9US made us think that this would be a shoe that would be hard to move. But nothing could be further from the truth. Once you put them on and start to put some miles on them, that predefined feeling disappears. They feel light and responsive thanks to the Fresh Foam X midsole. You can go for long runs with them without suffering more than necessary.

A well cushioned shoe when landing, very pleasant when transitioning and highly reactive when leaving the ground. Cushioning throughout the entire length and width of the New Balance Fresh Foam Iron V6 is very stable and homogeneous. This is also helped by their lugs, which are quite soft and with cushioning capacity to absorb hard landings.

The last and foot support also contribute to the pleasant feel. It is a last neither narrow nor wide, very normal in terms of measures that even if you have narrow feet, thanks to the flat and resistant laces, you can tighten them as much as you want until they fit you like a glove.


For the Hierro V6, New Balance has improved the weak points of one of the most well-finished ultra-trail shoes on the market. A more modern look, with a cushioning that excels in quality and performance, that will satisfy many runners looking for a model for long distance, not very technical and that prioritise cushioning and comfort over lightness.

 For who?

The New Balance Fresh Foam Hierro V6 are for neutral, medium-heavy runners (up to 95kg) who want a neutral shoe for long distance trail training at a medium to low level and medium to slow pace.


Outsole grip and traction

Fresh Foam cushioning



Somewhat heavy

Poor breathability


Brand: New Balance

Model Fresh Foam Hierro V6

Upper: – Engineered Mesh

Midsole: Fresh Foam X

– Sole: – Vibram Megagrip

Drop: 8mm -32mm heel and 24mm forefoot-

Available sizes: From 36EU to 55EU

Weight: 313g (in size 42,5EU)

Colours available Blue/Black/Brown, Red/Grey/Brown, Blue/Lilac/Black (women’s) and Maroon/Gold (women’s)

More information here

Test: New Balance Fresh Foam Hierro V6
New Balance Fresh Foam Hierro V6 The American brand New Balance, with more than 100 years of life behind it, has an important novelty for mountain runners in 2021. They are one of their most successful trail running shoes and one of the …
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Test: New Balance Fresh Foam Hierro V6

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