ShoesNew BalanceFresh Foam X Hierro v9

New Balance

New Balance Fresh Foam X Hierro v9

New Balance Fresh Foam X Hierro v9. 37.3mm stack, 309g. Retailer specs verified on Running Warehouse.

PR Run Verified
Soft trailsLong ultrasDaily training

PR Run scores

Grip2/5
Cushion5/5
Protection3/5
Durability4/5
Versatility3/5

PR Run derived fit scores

89Elite

100-miler readiness

Will this shoe survive a hundred-mile night? 37.3 mm stack, cushion 5/5

100Elite

Descent tolerance

Does it save your toenails on long descents? 33.1 mm forefoot, heel counter 3/5

100Elite

Swelling room

Room to grow when your feet swell? 26.7 mm toebox height

93Elite

Grit resistance

Does dust stay outside the shoe? 3 BR breathability

22Weak

Hot-day comfort

How well does it breathe in heat? 3 BR / ?% drying

81Elite

Achilles-friendly

Kind to a cranky achilles? 4.2 mm drop, heel counter 3/5

Full specs

Drop

4.2 mm

Heel stack

37.3 mm

Forefoot stack

33.1 mm

Weight

309 g

Lug depth

3.3 mm

Plate

No

Waterproof

No

Lab measurements

MeasurementValue
Breathability3 BR
Flexibility18.2 N
Heel counter3/5
Energy return61.9 %
Shock absorption131 SA
Midsole softness29.7 HA
Outsole thickness2.4 mm
Tongue padding7.2 mm
Insole removableYes
Insole thickness4.5 mm
Reflective elementsNo

Lab numbers from RunRepeat. Sources.

Fit intelligence

Toebox width

Narrow toebox (73.4 mm vs 96 mm median)

Toebox height

Slightly tall (26.7 mm vs 25 mm median)

Runs small. Consider a half size up.

Fit numbers from the lab. Swell guidance: foot care.

Questions before you race

Is the New Balance Fresh Foam X Hierro v9 good for 100-mile races?

Elite. 37.3 mm stack, cushion 5/5. 100-miler readiness score 89/100.

Does the New Balance Fresh Foam X Hierro v9 fit wide feet?

No. Toebox is 73.4 mm which is narrow. Look elsewhere if you need width.

What is the drop on the New Balance Fresh Foam X Hierro v9?

4.2 mm, with a 37.3 mm heel stack and 33.1 mm forefoot.

Is the New Balance Fresh Foam X Hierro v9 good on wet rock?

Lab traction has not been measured for this model yet.

Manufacturer specs · Retailer listing

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Image: Running Warehouse product photo

Specs: retailer. Verified Sep 2, 2026.

Report inaccurate data: hi@pr.run. Data sources.

New Balance Fresh Foam X Hierro v9 Review, Specs, and Fit (2026) | PR Run