Short answer
The New Balance Fresh Foam X Hierro V9 represents a strategic shift toward maximalist trail-running, prioritizing a technical, snug lockdown that ensures foot stability over its massive 42 mm stack height. True to size for standard widths; wide options available; narrow-footed users may find it slightly roomy.
Runs true to size
Cross-sizing: what size to buy
Find a shoe you already own and read across to the New Balance Fresh Foam X Hierro V9 size to buy.
| Reference Shoe | US | EU | ||
|---|---|---|---|---|
| Your usual | Buy | Your usual | Buy | |
| Nike Air Force 1 | 10 | 11 | 44 | 45.5 |
| Hoka Speedgoat 7 | 10 | 10.5 | 44 | 44.5 |
| New Balance 990v6 | 10 | 10.5 | 44 | 44.5 |
| Adidas Samba | 10 | 10.5 | 44 | 44.5 |
-
Nike Air Force 1
Your usual Buy US 10 11 EU 44 45.5 -
Hoka Speedgoat 7
Your usual Buy US 10 10.5 EU 44 44.5 -
New Balance 990v6
Your usual Buy US 10 10.5 EU 44 44.5 -
Adidas Samba
Your usual Buy US 10 10.5 EU 44 44.5
Fit Notes
- Nike Air Force 1
- The Nike Air Force 1 runs notoriously large (0.5 to 1 full size), while the Hierro V9 runs approximately 0.5 size small. To maintain a functional performance fit and avoid toe strike on trails, you should size up significantly from your lifestyle AF1 size.
- Hoka Speedgoat 7
- While both models are snug maximalist competitors, the Hierro V9 features a narrower toe box taper compared to the Speedgoat. A half-size increase is recommended to accommodate the Hierro's shorter length and prevent cramping during natural foot swelling on ultra-distance runs.
- New Balance 990v6
- New Balance Made in USA models typically run longer and roomier than their performance trail counterparts. If you normally size up in length for width in standard performance shoes, you can instead return to your true performance length (+0.5 from your MiUSA size) and leverage New Balance's 2E/4E width options for specific lateral relief without the excess length.
- Adidas Samba
- The Samba is a narrow lifestyle shoe but fits true to length. The Hierro V9 provides significantly more cushioning but a tighter technical lockdown and a shorter internal length, necessitating a 0.5 size increase for a proper performance fit.
Sizing FAQ
Does the New Balance Fresh Foam X Hierro V9 run true to size?
No, the general consensus from lab testing and user surveys is that the Hierro V9 runs approximately half a size small. Most runners need to size up by 0.5 to prevent their toes from hitting the 'Toe Protect' overlay, especially during the forward-leaning gait promoted by the shoe's 4 mm drop.
Is the New Balance Fresh Foam X Hierro V9 good for wide feet?
The standard D-width is notably narrow (94.7 mm) and restrictive, making it less than ideal for wide feet in its base configuration. However, New Balance offers the Hierro V9 in 2E (Wide) and 4E (Extra-Wide) options, which are highly recommended for those who need lateral relief and more room for toe splay.
How is the arch support on the New Balance Fresh Foam X Hierro V9?
As a neutral trainer, the Hierro V9 provides natural support through its dual-density Fresh Foam X midsole, which is firmer on the bottom for stability. While it feels supportive under the arch, the high 42 mm stack height may feel unstable for runners with severe overpronation, who might require stability-specific insoles.
Specs & Sizing
| Weight | 312 g |
|---|---|
| Retail price | $135 |
| Price on Amazon | $78–$104 |
| Release year | 2024 |
| Upper | Engineered mesh with fully injected TPU overlay for structure and foot-hugging fit |
| Midsole | Dual-density Fresh Foam X foam (approx. 3% bio-based content) |
| Outsole | Vibram® Megagrip rubber compound for high-traction performance |
| Technologies | GORE-TEX waterproof membrane (select models), Dual-density Fresh Foam X cushioning, Approx. 3% bio-based content in midsole foam |
| Fit & sizing | True to size for standard widths; wide options available; narrow-footed users may find it slightly roomy |