I ran 40 miles in the New Balance Fresh Foam X Hierro v9 — here’s my verdict

The New Balance Fresh Foam X Hierro v9 is one of the best trail-running shoes I’ve tested, but it won’t suit every runner out there. Its design focuses on comfort on lighter trails, rather than speed on more technical tracks, but it excels in its intended purpose thanks to its chunky stack of midsole foam.

I’ve been using the New Balance Hierro v9 on a mix of trails during my testing and have thoroughly enjoyed running in it. In my full New Balance Fresh Foam X Hierro v9 review I’ll explain what kind of runners it will suit and compare it to other top trail options like the Hoka Speedgoat 6.

New Balance Fresh Foam X Hierro v9 review: price and availability

The New Balance Fresh Foam X Hierro v9 was announced in late January 2025 and will go on sale on 25 February, costing $155, which is a $5 price rise on the Hierro v8. The price stays the same as the older shoe in the U.K., where the Hierro v9 will cost £140.

New Balance Fresh Foam X Hierro v9 review: design and fit

New Balance has made a lot of changes to the Hierro v9 compared with its predecessor, with one of the most notable being the increase in stack height. The Hierro v9 stands 42mm tall at the heel and 38mm at the forefoot for a 4mm drop, while the Hierro v8 was 38mm at the heel and 32mm at the forefoot with a 6mm drop.

This increase in cushioning also increases the weight a little, with my US men’s 9.5 Hierro v9 weighing 10.9oz. Given the high stack and substantial outsole on the shoe, that’s actually lighter than I expected, but the weight is a factor if you’re considering the shoe for faster trail runs.

I wore the same size in the Hierro v9 as I do for New Balance road running shoes and I found that my toes were a little cramped, especially on downhills. If you’re often in between sizes I’d opt for the larger one, especially if you have very long trail runs in mind and you need room for your foot to expand.

Upper

The Hierro v9 has a mesh upper with a lot of padding on the tongue and collar of the shoe to increase its step-in comfort. There are overlays on the upper and a stiff toe bumper to protect your foot on the trails, and an internal heel counter adds more structure and support at the back of the shoe.

I found the upper to be comfortable throughout my testing, though I wasn’t really able to check its breathability in hot conditions because I was running in the winter. Given the amount of padding on the tongue, I suspect some might find it gets too warm on longer runs in the sun.

Midsole

The dual-density midsole on the Hierro v9 contains two different types of New Balance’s Fresh Foam X material. The top layer is softer to increase the comfort of the shoe, while a firmer bottom layer ensures the shoe is still stable and increases its responsiveness.

Your foot sits within the foam surrounded by sidewalls, which again increases the stability of the shoe when running on uneven ground. While the Hierro v9 is not the right trail shoe for very technical tracks, I found it stable throughout my testing on tamer trails.

Outsole

The revamped outsole on the Hierro v9 is made from Vibram Megagrip rubber and has 4.5mm lugs. These are quite broad to ensure the shoe is comfortable on flatter, harder surfaces including roads, but have enough bite for softer ground as well as long as you stay away from very deep mud.

It’s an excellent outsole for a shoe that’s designed to handle a wide range of trails, and for most runners you’ll have more than enough grip in all conditions. I found the shoe provided enough traction on the road to and from the trails as well, and don’t see any signs of wear on the lugs after 40 miles.

New Balance Fresh Foam X Hierro v9 review: running performance

I did a range of training runs in the Hierro v9 across a variety of trails, mostly running on well-groomed if muddy forest paths, but also using it on grass, gravel and for spells on the road to and from the trails.

The weather was mostly wet and occasionally icy throughout my testing, so the impressive grip of the redesigned outsole was welcome and while I wouldn’t use the Hierro for runs in very deep mud or steep hill-running on grass when I’d want a shoe with longer lugs, it can handle most terrains well.

I used the shoe for mostly easy pace daily training runs, along with my Sunday long run of around 13 miles, and the comfort of the shoe certainly helps it to stand out from most trail shoes. If you like to feel the trails beneath your feet, this isn’t the shoe for you, but if you want a lot of cushioning and protection it definitely offers that.

That comfort comes at the expense of speed and agility though. While it doesn’t feel very heavy, the Hierro v9 is not the best shoe for faster runs, and its size detracts from its agility on twisting, technical trails or steep downhills.

Stick to tamer paths, however, and it’s ideal for cruising along, and the variety of terrain it grips well on will make it perfect for runners who spread their time across different surfaces and between the road and trails.

It’s also a good hiking shoe and as long as you don’t get it too muddy, it’s a great option for holidays when you want one set of shoes for runs and general use and you’re not sure what kind of terrain you’ll be tackling.

Should you buy the New Balance Fresh Foam X Hierro v9?

The New Balance Hierro v9 is a trail shoe that will work very well for some runners, including myself, but won’t suit others at all. If you mainly run on technical mountain trails and like nimble, lightweight shoes, the Hierro is not the shoe for you.

However, if you want a comfortable shoe that grips well on a variety of terrain, that you can use as a daily trainer without fear of coming unstuck the moment you step off-road, then it’s a top option.

Other versatile shoes like the Hoka Speedgoat 6 offer better grip and agility on technical tracks but aren’t as comfortable as the Hierro v9, which does bring the feel of a cushioned road shoe to the trails while adding stability and grip.