Onemix Flash Air Review: 150 km Tested by an Ultramarathon Runner
Italian athlete Amedeo Bonfanti shares his firsthand experience with the Onemix Flash Air.
With years of running experience and a deep understanding of training and performance, Amedeo provides a detailed evaluation of the shoe’s comfort, responsiveness, and durability. His insights come from real-world use, offering an honest perspective from an experienced runner who values reliability and performance across different paces.
The Onemix Flash Air is clearly positioned as the brand’s flagship model for 2025, featuring a full-length carbon plate and a performance-oriented design. After 150 kilometers of real-world testing, including a 6-hour race, I can now share a more complete and honest evaluation of where this shoe truly stands.
As an ultramarathon athlete, my priorities differ slightly from those of short-distance racers. Beyond speed, I look for comfort, durability, and protection over long hours, especially because plated shoes are often aggressive and suitable only for a narrow group of runners. Interestingly, the Flash Air does not fall into that category.
Comfort and Fit Over Long Distances
Comfort is critical when running for five to six hours, and this is where the Flash Air performs better than expected for a carbon-plated shoe.
The heel padding is generous, the tongue is well padded, and overall foot lockdown is excellent. Despite the sizing being slightly on the snug side, I experienced no blisters, even during long runs and race conditions.
One area that could be improved is the toe cap. At the moment, it feels too stiff. A softer structure or a plastic reinforcement with more flexibility would enhance comfort, especially for long-distance runners whose feet naturally expand over time.
Breathability is difficult to judge accurately, as all testing was done during winter conditions. However, based on the upper construction, airflow should be more than adequate in warmer weather.
Weight:
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Size US 11: 247 grams
Midsole, Plate, and Ride Feel
The Flash Air uses Onemix’s Supercritical Foam Midsole midsole compound. This foam sits firmly in the moderate range, clearly different from the very soft, highly compressed foams currently popular in many “supershoes.”
This is not a shoe designed around extreme softness. Instead, the midsole offers:
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Decent responsiveness
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Reliable impact protection
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Good stability, even for heel strikers like myself
The heel-to-forefoot transition is smooth, helped by a well-designed rocker geometry.
The carbon plate runs through the entire midsole, features a cut-out in the heel, and rises along the sidewalls. This construction adds noticeable stability without making the shoe feel overly rigid or harsh underfoot.
Outsole and Durability
One of the standout features of the Flash Air is the outsole durability. After 150 km, wear is almost nonexistent. Based on the current condition, I expect the shoe to comfortably last at least 600 km, which is excellent news for runners looking for longevity in a plated model.
Performance Across Different Paces
The Flash Air proved to be extremely versatile during testing.
In a 6-hour race, I ran at:
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4:25 min/km at the start
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Slowing to 5:45 min/km later due to fatigue and physical issues
Throughout this range, the shoe consistently provided protection and comfort.
I also tested faster segments at under 4:00 min/km, where the shoe felt responsive and efficient, confirming that it can handle speed when required.
Final Thoughts
The Onemix Flash Air is not a traditional supershoe built exclusively for elite-level racing at maximum intensity. Instead, it offers something more versatile:
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A carbon-plated shoe that remains comfortable over long distances
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Suitable for both fast and slower paces
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Durable enough for high-mileage runners
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Stable and protective, even for heel strikers
For runners who want one plated shoe that can handle a wide range of paces without sacrificing comfort, the Flash Air is a surprisingly well-balanced option.
