Asics Magic Speed 4 Review

Introduction

The Asics Magic Speed 4 in its vibrant blue colourway is a carbon-plated supershoe that’s got me hooked, promising speed and cushioning that’s hard to resist. At runclever.com, we usually test shoes for a full 12 months to see how they handle every condition, from wet pavements to dry trails. But we’re bending our rules this time. Why? This is our first supershoe review, and after six months, from April 2025 to October 2025, including a marathon, I’m bursting to share my experience. What you really want to know is, how fast is this shoe? Using our RunClever Ratings ©, we’ve measured its speed, and the results are impressive. The Magic Speed 4 brought a strange new feeling, left my calves aching as I got used to it, and acted like a personal trainer, pushing me to run faster and keep up the effort. It’s the best shoe I’ve ever worn, but non-supershoes now feel like a step backwards. After 247 miles, I’m ready to explain why this shoe is a game-changer, though it has its quirks.

Key Specifications

Here’s the quick rundown on the Magic Speed 4’s specs:
• Weight: 237g (men’s), 207g (women’s)
• Drop: 8mm
• Cushioning: FlyteFoam Blast+ with FlyteFoam Turbo insert, high
• Stack Height: 43.5mm heel, 35.5mm forefoot
• Fit: True to size, snug midfoot, slightly tapered forefoot
• Price: £170 (RRP in 2024)
• Category: Road, carbon-plated supertrainer
• Target Audience: Neutral runners seeking speed for tempo runs, races up to half marathon, or marathon with sustained high effort

Design and Technology

The Magic Speed 4 blends supershoe tech with trainer durability, making it a standout. Its midsole combines FlyteFoam Blast+, a firm, stable foam, with a forefoot insert of FlyteFoam Turbo, Asics’ lively, nitrogen-infused foam. This pairing creates a bouncy, propulsive kick that feels like a spring underfoot. A full-length carbon plate, gently curved in the forefoot, adds snap to your toe-off, delivering that addictive supershoe propulsion without the harshness of elite racers. The stack is huge, 43.5mm in the heel and 35.5mm in the forefoot, packing serious cushioning, though it’s not race-legal for elites due to World Athletics’ 40mm limit. The ASICSGRIP outsole provides excellent traction, sticking like glue on wet roads with no visible wear after six months. The engineered mesh upper is lightweight and breathable, offering a secure lockdown, though the snug midfoot and tapered toe box might feel tight for wider feet. The blue colourway is bold, with Asics offering other colour options. My main issue is the snug fit, which needed breaking in, and the 237g weight, light for a supertrainer but heavier than pure supershoes. Compared to the Magic Speed 3, the 4 has a higher stack and softer Turbo insert, boosting the bounce. The meta-rocker geometry tilts you forward, enhancing propulsion but taxing your calves, as I learned early on. After 247 miles, the upper showed slight fraying at the flex points, but the outsole looked nearly new, suggesting great durability. The Turbo foam stayed energetic, though the Blast+ base felt a bit firmer after 200 miles, without losing much zip.

Performance and Testing

From April to October 2025, I logged 247 miles in the Magic Speed 4 across 56 runs, covering short intervals, tempo runs, and a marathon on roads and light gravel paths. The first runs were wild, with a strange new feeling, like running on springs. The carbon plate and FlyteFoam Turbo gave a propulsive, bouncy sensation, unlike any trainer I’d tried. It was like having a personal trainer on my feet, urging me to pick up the pace and maintain at least 90% effort. My calves ached for the first 30 miles as I adapted to the stiff plate and aggressive meta-rocker, which pushes you onto your forefoot. It felt like a tough workout, but once my legs adjusted, the shoe unlocked a new level of speed.It excels at uptempo runs, from 5K to half marathon, where the plate and Turbo foam deliver a snappy, efficient ride. I felt faster, with smoother transitions and less ground contact time, as our RunClever Ratings © confirm with strong gains in shorter distances. The ASICSGRIP outsole was flawless on wet roads, gripping tightly through sharp turns in rain. But the 237g weight made slower recovery runs feel clunky, and the narrow midsole, built for speed, reduced stability on longer runs, causing foot fatigue past 15 miles. The shoe held up well, with minimal fraying and an outsole showing little wear after 247 miles. The Turbo foam stayed lively, though the Blast+ base stiffened slightly after 200 miles. This shoe has spoiled me, as non-supershoes now feel flat and sluggish, like switching from a race car to a hatchback. It’s the best I’ve ever run in, but its demanding nature isn’t for everyone.

Marathon Performance

In May 2025, I ran the Leeds marathon in the Magic Speed 4s, and it was a tale of two halves. The first 13 miles or so, were incredible. The carbon plate and FlyteFoam Turbo launched me forward with a springy, almost effortless stride, like I was being propelled, especially on the downhill. My splits were faster than ever, and the shoe’s tight lockdown kept my feet secure at race pace. The cushioning absorbed impact beautifully, and the meta-rocker made every stride smooth and efficient. I couldn’t help but start thinking this was the ultimate marathon shoe. But as the miles went on, reality hit. The Magic Speed 4 isn’t designed for long distances if you can’t sustain near-max effort. By the halfway point, my calves were aching again, and the narrow midsole felt unstable as fatigue set in. The firm ride, perfect for speed, turned punishing when my form slipped. I couldn’t maintain the 90% effort the shoe thrives on, and the second half was a grind. The first 13 miles were a Half Marathon PB for me, but the second half was 40 minutes slower… and the last stretch was beyond tough. This shoe is a speed machine for runners who can hold high intensity for 26.2 miles, but for most of us, it’s better suited to 5K, 10K, or half marathons, where its propulsion shines without exposing its limits.

Fit and Sizing

The Magic Speed 4 fits true to size, but the snug midfoot and slightly tapered toe box might feel tight for wider feet. The engineered mesh upper is breathable and secure, like a race-day shoe, with no blisters or hot spots, even sockless. The semi-gusseted tongue stayed put, and the moderately padded heel prevented rubbing, though thin socks worked best due to the snug fit. It took about 20 miles to break in, as the upper was initially stiff. After 247 miles, the upper stretched slightly but held its shape. Runners with custom insoles might need a half-size up, as the forefoot is low-volume.

Pros and Cons

Pros:
• Unreal propulsion from carbon plate and FlyteFoam Turbo.
• Excellent traction with ASICSGRIP on wet roads.
• Breathable, secure upper for fast runs.
• Durable for 200–250 miles, even as a supershoe.
• Variety of colour options, with the blue standing out. Cons:
• Snug fit may pinch wider feet.
• Narrow midsole limits stability for long runs.
• Calf strain during adaptation period.
• Firm ride reduces comfort for slower runs.

Who It’s For

The Magic Speed 4 is perfect for neutral runners chasing speed in tempo runs, speed workouts, or races up to a half marathon. It’s ideal for intermediate to sub-elite runners logging 20–40 miles a week who can sustain 90% effort during races. The carbon plate and Turbo foam act like a personal trainer, pushing you to run faster, but they punish sloppy form or fading effort. Our RunClever Ratings © show it excels for 5K and 10K, with solid performance in half marathons, but it’s not suited for marathons unless you can maintain high intensity. Runners needing stability or softer cushioning should try the Asics Gel-Kayano 32 or Gel-Nimbus 27.

Pricing and Value

At £170 (RRP in 2024), the Magic Speed 4 is a great value for a carbon-plated supertrainer, undercutting elite supershoes like the Asics Metaspeed Sky Paris (£250) or Nike Vaporfly 3 (£240). After 247 miles, the outsole showed minimal wear, and the upper had slight fraying, suggesting a 200–250-mile lifespan for my 25-mile weeks. Heavier runners might get closer to 200 miles. Its durability and performance make it a worthwhile investment for speed-focused runners, though its stability issues limit its use for long races or recovery runs. Discounts at retailers like Asics UK can make it an even better deal.

Conclusion

After six months with the Asics Magic Speed 4, from April to October 2025, I’m convinced it’s the best shoe I’ve ever run in. Its carbon plate and FlyteFoam Turbo deliver a strange, springy propulsion, like a personal trainer demanding faster runs. My calves ached for weeks as I adapted, but once I did, it transformed my training, boosting performance by +17.98% in our RunClever Ratings © below. The marathon was thrilling for the first 13 miles but tough when I couldn’t sustain 90% effort, proving it’s not built for long distances unless you’re at peak intensity. Non-supershoes now feel sluggish, like I’ve been spoiled by a rocket. Despite its snug fit and stability quirks, its value and durability make it a standout for speed-focused runners.

Distance	Number	Performance vs. Expected PRR
Short Distance Runs (e.g., 5K)	20	+21.62%
Middle Distance Runs (e.g., 10K)	19	+18.47%
Long Distance Runs (e.g., Half Marathon)	17	+12.84%
Total Runs	56	+17.98%