Review: Hierro v4

Written by

Henry Howard

Ultra runner and certified running coach.

This expert review is written by

Henry Howard

Ultra runner and certified running coach.
Henry Howard has come a long way since a teacher called him "molasses" during a fifth-grade track and field event.

Now living and running in Indiana, he has completed more than a dozen marathons and is a regular age-grouper in shorter distances.


We usually consider 10 ounces a "medium" weight for a running shoe: less than 10 and we are entering the lightweight category and above 10 the shoes start to be heavy.

Heel-to-toe drop

Heel drop is the measurement in mm of the difference between the height of the heel and the toe of the sole.

A lower drop (0mm - 5mm) promotes running on mid-foot and fore-foot, while higher drops (8mm - 12mm) are more traditional and meant to support a heel-striking gait.
Expert score

Quick overview

Best for
Long, slow training runs, ultra distances, 50 miles and greater
Best for on dirt trails, over very rocky area, along highly technical trails
The Hierro v4 provides good traction on most types of terrains and surfaces
Lack Traction
Average Traction
Provide Traction
The Hierro v4 is maximally cushioned
Little cushioning
Medium cushioning
Highly cushioned


323 g
Heel to toe drop



Pros and cons according to our running expert

Pros and cons according to our running expert

  • Superior protection
  • Rugged and can handle all sorts of terrain
  • Colors match most trail and hide dirt
  • Time consuming to actually put on and take off
  • Bulky, feels like a hiking boot
  • Colors are ugly

Our verdict

The New Balance Hierros are built for the trail runner who seeks protection and has patience in getting his or her feet into the shoes.

The shoes are rugged, offer superior protection and the color schemes mask the natural colors of most trails. For me, the shoes represented more of a slimmed-down hiking boot that would not be among my top choices for most trail runs.

Introduction Hierro v4

The fourth version of the Hierro (8mm drop) has its share of supporters. Among them: runners who seek out debris-riddled trails, off-the-beaten-path adventures and/or significant climbs.

A reinforced toe cap complements the toughness New Balance packs into the makeup of the rest of the shoe.

Cushioning Type
The Hierro v4 is more responsive than plush:... Read more provides energy return and some shock
Cushioning Amount
The Hierro v4 is maximally cushioned
Little cushioning
Highly cushioned
The Hierro v4 is quite rigid and does not... Read more flex easily
The Hierro v4 has some inherent stability and... Read more support
Not particularly stable
Very stable

Impressions Hierro v4

New Balance’s commitment to a protective shoe also extends to the bottom. The aggressive lugs and the breathable forefoot combine to provide support and confidence for the runner.

Overall, the Hierro V4 didn’t change much from its predecessor, but it did remove some of the hypo-skin that coated the v3’s upper.

Some of that layer remains and it does a decent job of protecting the feet from water and creating a more breathable shoe.

I would expect the Hierro V4 to last hundreds of challenging miles. The built-in Vibram Megagrip provides dynamic traction on challenging trails, rocky mountains and debris-filled surfaces.

I would not recommend it for road runners. Though it would work well in virtually any type of weather.

However, I found the Hierros (11.5 ounces for men; 9.4 ounces for women) to be bulky, slower to respond and a pain to get on and off my feet.

The narrow opening for the feet does it job in keeping debris out. At the same time, it takes a significant amount of time to wrestle one’s feet into place.

That may not be a big deal when starting out on a casual training run or long day in the mountains. But on race day, or when in a hurry, it’s a significant drawback for the shoes.

While I rarely consider the color options of my running footwear, I did find the earthy, brownish tones of these shoes to be a turnoff.

Protection Hierro v4

New Balance understands the niche it is trying to fill here. The Hierros are designed from top to bottom and heel to toe to accommodate runners on technical trails.

In addition to the shoe’s aforementioned attributes, the Hierros boast a sturdy rubber in the toe bumper to handle rocks, roots, sticks and more.

Feet are secured in the Hierros, thanks to its ankle-hugging upper. In doing various trail miles, I never felt like the shoes were working against my feel.

They were secure and could traverse rocks and other obstacles with confidence.

The rock plate in the Hierro v4 provides... Read more great protection from sharp rocks on the
Not present
Solid protection
The Hierro v4 provides good traction on most... Read more types of terrains and surfaces
Lack Traction
Provide Traction
Water resistance
The Hierro v4 provides a decent protection... Read more from splashes and puddles
Water Resistant

Durability Hierro v4

The Hierros are not only built to withstand the challenges of the trail, their construction is intended to be durable.

After 50ish miles, the shoes did not seem to show any wear or tear from the pounding I gave them.

While my trail miles were not on highly technical terrain, I have no doubt that they would be able to withstand a similar pounding on more technical trails.

Responsiveness & Speed Hierro v4

Oftentimes, trail and ultra runners make a choice: single-track trails where they can push their speed, or technical trails that are great for climbing at slower paces.

For runners with the New Balance Hierros, speed is not part of the equation.

Even on single-track trails with minimal turns, trail obstacles of hills, the weight of the Hierros held me back from hitting top speeds.

But that’s not whats they are built for. Expect the Hierros to excel on highly technical terrain, just know that you won’t be able to accelerate fully with them.

Comfort and Fit Hierro v4

New Balance’s Fresh Foam offers a good amount of cushion with a sponge-like, dual-density padding underneath. I would say it’s about average when compared with other trail shoes in its class.

The cushioning contributes to the overall protection when encountering trail debris and obstacles. The outsole is Vibram and offers excellent traction.

I did find the fit of the Hierros to be tight. Even after 50 miles, the shoes never loosened up to provide comfort when running.

I would consider the fit to be tight, though others who have run in these shoes say that the fit — primarily in the toe box — is better than in previous models.

The Hierro v4 has average sizing: buy the... Read more usual size
Buy size smaller
Buy size bigger

Conclusion Hierro v4

I can see why the Hierros have their supporters, though I am not one of them.

For runners who regularly trek through trails with unrelenting debris, these shoes would bring welcome relief from hard pebbles, dirt clumps and other annoyances that don’t belong in one’s shoes.

Additionally, those who take to the mountains for their adventures would also find these shoes to their liking.

But for me, it was difficult to get past the difficult in getting the shoe on and the lack of comfort during a run.

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