ASICS Magic Speed 4 review

We've tested the Magic Speed 4 in the lab and here's why we highly recommend it:

• It's an ideal choice for those seeking the dynamic feel of a carbon-plated shoe without the high cost, delivering excellent value.
• It's a resilient training partner to the more expensive Metaspeed series from ASICS, combining durability with performance.
• Provides superior cushioning for heavyweight heel strikers that run with a neutral footstrike.

While the Magic Speed 4 incorporates a carbon plate, its lack of a full-length superfoam and a lighter construction significantly diminish its appeal for those seeking top-tier performance. Instead, we suggest the ASICS Metaspeed Sky Paris, which, though considerably more expensive, it provides superior speed, lightness, and energy return, leading to faster finish times.

Additionally, we think the Magic Speed 4's less-than-ideal support could pose challenges for runners who prefer a stable ride. From our testing experience, we found that both the Hoka Mach X and the ASICS Superblast 2 offer superior stability, exceptional cushioning, and impressive energy return, making them much better choices in the supertrainer category.

In our humble opinion, ASICS is excelling with their latest upper designs, introducing asymmetrical patterns to enhance airflow while achieving exceptional breathability.

The Magic Speed 4 shines as a prime example, earning a perfect 5-out-of-5 score in our smoke test for its superbly ventilated toebox area.

With a light, we pinpointed the thinnest areas of the engineered mesh upper—not just in the toebox but also along the sides, enhancing breathability, though this slightly reduces stability, as we will show later in this lab review.

We then examined the upper under a microscope and noted that ASICS employs a classic engineered mesh with tiny openings, backed by a secondary thin fabric layer.

The upper is notably stretchy, comfortable, and aesthetically pleasing too! We also found that it's mostly seamless in critical areas, suggesting that it could comfortably be worn without socks—a definite improvement over its predecessor.

After confirming fantastic airflow in the toebox area, we next evaluated the upper's durability—essential for a shoe priced well over 150 bucks.

We were pleased to find it exceptionally durable at 4/5 in our books—the asymmetrical design we discussed earlier really shines here. ASICS intelligently placed numerous ventilation holes on the outer side while keeping the inner side denser to enhance durability and prevent damage from the big toe.

There's always some concern about the durability of speed training shoes, particularly in areas like the heel collar. However, our fierce testing with a Dremel tool alleviated these worries.

We found that the heel collar is well padded and durable, earning a solid 4 out of 5 here in the lab. This fantastic score provides reassurance that the shoe will withstand wear without any issues.

Having been thoroughly impressed with our initial lab tests, we now turn our attention to the outsole of the Magic Speed 4, which appears promising, sporting the same elite ASICSGRIP compound found in ASICS' premier shoes.

Upon applying our Shore C durometer to the rubber, it registered a softer-than-average reading of 71.5 HC. This explains the exceptional grip we experienced, although it raises concerns about potential durability trade-offs. We're eager to see how it holds up when facing our Dremel.

We conducted our durability test on the outsole of the Magic Speed 4 by setting our Dremel to 10K RPM to replicate extreme wear conditions.

Remarkably, the damage was minimal, with only a 0.9 mm indentation measured with our tread depth gauge. Though other supertrainers have exhibited superior durability, this wear on such a soft rubber compound is truly impressive!

To ensure robustness, ASICS opted for a 2.4 mm thickness in the outsole of the MS4, surpassing the standard for most supershoes.

This positions the Magic Speed 4 as a superb choice for those wanting the stiff ride of a carbon plate-enhanced shoe without the ultra-high cost, and with added durability in the outsole.

While the Magic Speed 3 was celebrated for its featherweight design at just 7.4 oz or 211g, the Magic Speed 4 unfortunately sees a weight increase, tipping the scales at 8.4 oz or 237g. Though still within the lightweight category, we understand that this increase could be a disappointment for some. 

The added ounce primarily results from the boosted stack height—an acceptable trade-off for many runners. Now, let's delve into the cushioning details.

While the MS3 served well as a speed training companion, it lacked the stack height to earn our "supertrainer" endorsement. The Magic Speed 4, however, boasts a colossal heel stack of 42.5 mm.

Yet, it's not without compromises—particularly in weight and stability. On the upside, the superior heel cushioning makes the MS4 a far better choice for heavier runners or those using it for long runs.

Additionally, its 42.5 mm stack height surpasses the World Athletics' road race limit of 40 mm. However, this shouldn't concern most runners, as those adhering to these regulations will likely opt for god-tier race-day-legal shoes like the Nike Alphafly 3 or the Hoka Rocket X 2, rather than a speed training model like this.

The forefoot features substantial cushioning at 32.9 mm, comfortably surpassing the 30-mm mark.

Coupled with the addition of FF Turbo and the carbon plate, we can highly recommend this shoe for midfoot and forefoot strikers alike.

Our two previous measurements uncovered that the Magic Speed 4 boasts a heel-to-toe drop of 9.6 mm, slightly above the 8 mm ASICS advertises.

This discrepancy is minor—only 1.5 mm, which is hardly noticeable.

The insole is noticeably thinner than what we typically encounter in our lab tests, and we like it. Given the shoe's towering height, adding even more millimeters with the insole doesn't seem like a good choice.

ASICS has designed a complex midsole featuring three different foams—two layers of FF Blast+ and one insert of FF Turbo. We'll examine each component, starting with the top layer situated above the carbon plate.

This top foam is the same FF Blast+ used in many of ASICS' most popular daily trainers, such as the Nimbus 26. We tested its plushness by pressing our durometer against it, registering a 14.9 HA. This layer provides significant comfort, effectively balancing the plate's inherent rigidity.

Should you expect massive energy return from FF Blast+? Not really. It's a mid-tier foam, providing a responsive ride but not on par with PEBA-based foams like ZoomX or PWRRUN PB. However, this aligns with our expectations, as this model isn't ASICS' premier running shoe.

The secondary foam, positioned below the plate, is not FF Turbo but another layer of FF Blast+.

This layer is considerably denser, engineered for enhanced stability and durability. In fact, we measured its hardness at 18.1 HA, a difference that's definitely noticeable with every ground strike during a run.

This setup mirrors the classic dual-density configuration seen in supershoes like the Vaporfly since 2017—so, really, there’s nothing groundbreaking here.

For the first time in the Magic Speed series, ASICS has integrated FF Turbo foam. Finally!

The only way to determine the amount of FF Turbo in the midsole is by slicing the shoe in half, which is exactly what we did here in the lab.

This piece of nylon-based foam is positioned under the plate in the forefoot, offering an enhanced bounce over FF Blast+ that is especially noticeable for forefoot strikers.

FF Turbo comprises only a small portion of the midsole, yet it's advertised here as if it were full-length. Not fair at all.

Does this mark a significant change? Not really. This slab (17.0 HA) is too small to revolutionize the shoe, and we're hopeful that ASICS will incorporate a full-length layer of FF Turbo (or even FF Turbo+ if they don't mind) in future versions of the Magic Speed. For now, though, it's an improvement over previous models.

FF Blast+, though based on EVA, is enhanced with Olefin Block Co-Polymers (OBC) which boost its performance, particularly in cold temperatures. Impressively, we noted only a 15.8% variance in softness between our standard room-temperature test and after chilling the shoe for 20 minutes in the freezer. Amazing!

As we've previously noted, this supertrainer incorporates a carbon-fiber plate similar to those used in many of the world’s top marathon shoes. However, there’s a subtle twist—we discovered that ASICS adjusted it slightly for training, making it gentler on the calf muscles.

Indeed, it occupies a middle ground, more curved than the flat plate found in the Metaspeed Sky Paris but less so than the spoon-shaped plate in the Nike Vaporfly 3. It's distinctly curved in the forefoot, yet moderately so.

We discovered that the ASICS Magic Speed 4 boasts a significant meta-rocker, helping with turnover for midfoot and forefoot strikers.

While its heel isn't as rockered as the Hoka Cielo X1, it strikes a balanced approach, optimizing it for faster paces where most runners naturally land more on their forefoot.

While the Magic Speed 3 wasn't exactly known for superior stability, the fourth iteration has taken an even steeper dive in this department—a more significant downgrade than even its weight.

The Magic Speed 4 is taller and retains its narrow build and pliable heel counter, resulting in reduced stability, making it suitable only for neutral runners. Thus, we strongly advise anyone needing support to steer clear of the MS4!

With the Magic Speed 4 featuring a carbon plate rather than the nylon plate found in other supertrainers, we anticipated a max score in our manual assessment—and it earned a 5/5.

However, its extremely stiff underfoot feel makes it less than ideal for easy runs. Clearly, while maybe it's not entirely magical, the shoe is built for speed.

We discovered that ASICS added extra padding to the heel counter of the Magic Speed 4, aiming to boost comfort beyond that of a typical competition shoe. However, the heel remains exceptionally pliable, offering minimal resistance to pressure and scoring just 1 out of 5 in our tests.

Further proof of the Magic Speed 4's lack of support can be seen in the dimensions of its midsole—our measurements showed only 109.6 mm in the forefoot.

This is notably narrower compared to most supertrainers, reinforcing that this model is really only suitable for runners with a perfect neutral stride.

The same issues affect heel strikers with the MS4, as it proves to be slightly narrower than most running shoes at 87.4 mm. While this isn't a major concern and does enhance its agility, we think that for training purposes, a bit more width in this area would be beneficial, especially for long run workouts.

Equipped with a carbon plate, we expected a sky-high performance in this test. However, ASICS has moderated the plate's stiffness—it only required 38.5N to flex it to 90 degrees in our lab.

We think this adjustment is wise, as an overly stiff plate might slightly improve running economy, but it significantly compromises comfort and can lead to fascia issues for many runners. And once more, this is designed as a performance-oriented training shoe, not solely as a competition speedster.

During our performance evaluation comparing mild to cold temperatures, the Magic Speed 4 performed exceptionally well for the second consecutive time. It showed only a 21.8% increase in stiffness, demonstrating its consistent performance even in freezing conditions.

The midsole is notably narrow for its category, and the upper is similarly snug. We experienced a fit akin to racing shoes—tightly embracing our feet and providing an exceptionally secure lockdown, though it offers little space too.

For those who prefer more spacious uppers, the MS4 will disappoint. Measuring just 95.0 mm at its widest, it presents a decidedly narrow fit, take it or leave it. And sizing up won't remedy this; we think it's better to opt for a wider option, like the On Cloudmonster Hyper.

Fortunately, we discovered that ASICS' designers generously shaped the toe cap of the Magic Speed 4, which is decently rounded at 78.7 mm. This design is great for toe splay, and it also underscores the value of taking two measurements in the toebox area as we do.

Another nice feature of the Magic Speed 4's upper is its high vertical volume, which, like most recent ASICS shoes, we found to be quite satisfactory. We hope other brands will adopt this design, as a low-volume upper can truly detract from an otherwise excellent shoe.

This was definitely a delightful surprise—a subtle hint from ASICS suggesting that they still view the Magic Speed 4 more as a training shoe than a racing option. We think this because the Japanese brand typically reserves semi-gusseted tongues for their training shoes, and they've used this design in the Magic Speed 4.

The Magic Speed 4's tongue is exceptionally thin, equipped with just 1.0 mm of padding—offering minimal protection across the instep and aligning with the lightest competition shoes on the market.

It clear to us that ASICS, in an effort to reduce weight elsewhere due to the added cushioning in the midsole, significantly minimized the tongue's bulk from v3 (2.9 mm), which noticeably impacted comfort.

We discovered that ASICS opted to mirror the heel design of the Metaspeed series, meaning it completely lacks a finger-loop tab.

Our tests revealed that ASICS designed this insole without gluing them to the last, a feature that offers flexibility for those who prefer or need custom footbeds.

Despite this, we recommend keeping the stock insole—it's a premium one with perforations that enhance heat dissipation.

The Magic Speed 4 lacks any reflective elements on the entire upper.