ASICS S4+ Yogiri review

The ASICS S4+ Yogiri is an entry-level option in the carbon-plated category, and based on our lab testing and runs, it targets:

• Beginners or heel strikers searching for their first carbon shoe, as we found the ride stable in our runs.
• Runners who are not ready for full super shoes due to price or stability concerns.
• Those who want the feel of a carbon plate without needing top-tier energy return, which we discovered is exactly the gap this shoe fills.

From our perspective, we do not recommend the S4+ Yogiri as a primary racing shoe. In our lab tests and runs, its firm ride and modest energy return lag behind every real super shoe. ASICS’ own Metaspeed Sky Tokyo and Metaspeed Edge Tokyo deliver clearly higher performance for slightly more money. And for beginners, the Saucony Endorphin Pro 4 is a better pick.

In our opinion, it also falls short as a carbon-plated super trainer. Its limited versatility and narrow speed range make it hard to recommend, and we firmly believe there are better options available, like the Nike Zoom Fly 6. 

Shock absorption sits at an average level in both ends of the shoe, with 130 SA in the heel and 108 SA in the forefoot. It’s not a standout result for a racing shoe, and it further highlights the downsides of pairing FF Turbo+ with FlyteFoam.

For us, the biggest drawback of this shoe is energy return. With just 60.5% in the heel and 65.2% in the forefoot, the S4+ Yogiri is not very impressive for being a competition running shoe.

FF Turbo+ is PEBA-based and proved in our lab to be a top-tier foam, but FlyteFoam delivers very poor bounce. It’s hard to justify its presence in a $200 shoe, especially when we measured only 44.2% energy return in FlyteFoam-only models like the ASICS Gel Pulse 15.

The S4+ Yogiri packs a 36.9 mm heel stack, putting it very close to the 40 mm limit set by World Athletics. That said, it hardly matters, as runners chasing serious competition are far more likely to line up in the Metaspeed series instead.

The forefoot measures 28.4 mm, delivering solid cushioning without pushing into extreme heights that could hurt stability and compromise one of the shoe’s most appealing strengths.

ASICS clearly positions this model as an entry-level option for carbon-plated shoes, which explains the higher drop compared to the Metaspeed series. The S4+ Yogiri features an 8.5 mm offset that better accommodates heel strikers.

This shoe delivers a firm ride, we felt it from the first step. You really need to be comfortable with that feel, as it sits at the complete opposite end of the ultra-soft Metaspeed Ray.

Most of that firmness comes from the EVA-based FlyteFoam. We measured 22.9 HA on our durometer, and we found it neither bouncy nor comfortable. We believe FF Blast+ would have been a better option here, while FF Blast Max would have been the ideal choice.

The secondary foam layer is FF Turbo+, a PEBA-based compound with a softer 17.8 HA reading and strong energy return. Placed closer to the foot, it adds bounce, while the FlyteFoam below handles ground contact and stability.

But again, it’s disappointing that FlyteFoam dulls the ride and makes it overly firm, because this FF Turbo+ layer is genuinely very good.

The side profile of the S4+ Yogiri follows modern racing shoe norms, with a clear toe spring and minimal heel curvature. Still, thanks to the plate shape and the higher drop, heel strikers remain well supported.

The ASICS S4+ Yogiri uses a very stiff, full-length carbon plate that's inherited from the Metaspeed Edge series, featuring a slightly inclined rear and midfoot section that helps smooth transitions, especially for rearfoot strikers.

When we first tried the S4+ Yogiri, we immediately felt that the toebox design leaned much more toward pure racing than daily training.

Later, we made a gel mold of the shoe and measured a width of 93.0 mm, which is clearly narrower than the average running shoe.

Our second measurement fully confirmed what we felt in the S4+ Yogiri, dropping to just 70.5 mm in the big toe area. That’s clearly not good news for runners with wider feet.

When it comes to toebox height, the S4+ Yogiri follows the familiar ASICS approach from the past three years. 

The rounded toe cap provides enough vertical room for the toes to move comfortably.

While there’s still room for improvement in the midsole, the outsole tells a completely different story. It’s outstanding. We tested it in the lab and recorded an incredible 0.93 score, breaking the previous 0.90 barrier and making it the grippiest road shoe we’ve ever measured at the time of this writing.

So how did ASICS pull this off? It comes down to the excellent ASICSGRIP rubber. As you can see, many of the highest-ranking shoes in our traction tests use this compound, and the S4+ Yogiri packs even more of it than the Metaspeed series, resulting in superb grip on both dry and wet surfaces.

Because this shoe targets newer runners and heel strikers, ASICS added more rubber across the entire outsole, especially under the heel and midfoot. We found that the extra ASICSGRIP reduces exposed foam, increasing weight slightly but clearly boosting traction and durability.

The full-length carbon plate and the firm foam work together to create a stiff ride, which we confirmed with a 20.0 N result in our 30-degree bend test.

The ASICS S4+ Yogiri is slightly heavier than most super shoes for two clear reasons. First, the EVA-based FlyteFoam layer adds more weight than PEBA or A-TPU premium foams. Second, the outsole uses more rubber, which also increases mass.

Even so, the final weight stays reasonable at 8.3 oz or 235g. It’s heavier than all top-end shoes, but considering the materials, cheaper price and design choices, the weight feels justified.

The upper uses an engineered mesh that did not look very breathable at first glance, so we decided to test it right away using our full set of lab tools.

We started by feeding smoke directly into the toebox with a custom 3D-printed adapter, allowing us to control airflow precisely. Ventilation was clearly poor, which led us to score it just 2/5.

Next, we moved the upper against a strong light source and found that the tongue was the only area letting noticeable light through. The rest of the upper is simply too thick.

We then confirmed these results under our digital microscope.

The tightly packed yarns leave very little space for air to move, making airflow highly restricted.

In our opinion, a racing shoe like the S4+ Yogiri should prioritize breathability, even if that means giving up some durability. ASICS clearly chose a different direction with this upper.

The S4+ Yogiri is far from a true stability shoe, but it stands out as one of the more stable racing models thanks to its firm foam. This reinforces ASICS’ intent to position it as an accessible entry point into the competition category.

With a full-length carbon fiber plate, it came as no surprise that torsional rigidity scored a 5 out of 5, resulting in an extremely stiff feel.

The heel counter offers more structure than a daily trainer but less than a true super shoe. This is another clear sign that ASICS aimed to add a touch of stability without going too far.

The S4+ Yogiri has compact dimensions and feels very agile, which makes it a solid option for track workouts and one of the reasons why it can be more interesting for many as a training tool than a pure racing weapon.

In the forefoot, we measured a below-average width of 110.7 mm.

The heel is clearly aggressive at just 77.3 mm, showing that the Japanese designers drew heavy inspiration from the Metaspeed series when shaping the midsole. That said, the firmer foam makes heel striking more manageable here, unlike in many other super shoes where it’s strongly discouraged.

The benefit of using a denser upper than most racing shoes is clear in durability, as it scored 3/5 instead of the usual 1/5 we often see in this category.

The heel also held up well in our Dremel test, earning a strong 4/5 score, which points to solid durability in this high-wear area.

ASICSGRIP rubber truly stands out for traction, but durability is not world class. After our Dremel test, we measured 1.4 mm of wear, which is clearly higher than average.

ASICS kept the rubber thin to save weight, which makes sense for a competition-focused shoe. We measured just 1.5 mm, clearly on the thin side, but that trade-off feels justified, as adding more rubber would only make the shoe heavier.

The insole is also quite thin, measuring just 3.1 mm.

It’s nice to see that ASICS added a few premium touches to the S4+ Yogiri, like a perforated insole that helps improve ventilation inside the shoe (which is much needed) while also shaving off some weight.

After leaving the S4+ Yogiri in our freezer for 20 minutes, we measured an 11% increase in firmness, which is a very good result.

The upper has no reflective elements, and it’s actually rare to find a competition shoe that includes them, like the Mizuno Wave Rebellion Pro 3.

Despite being a lower-priced competition shoe, ASICS added some premium touches that we noticed right away in our testing, like the textured laces borrowed from the Metaspeed series. It’s a welcome detail, especially when some much pricier shoes from other brands like Adidas or Mizuno still come with average laces.

The tongue also leans fully into performance and skips comfort. We measured just 0.7 mm of padding, paired with heavy perforations to save weight and help offset the poor breathability of the toebox.

The tongue isn’t gusseted, and while that makes sense in the Metaspeed line due to the extreme focus on weight savings, we think adding a gusset here would have been a welcome improvement.

The ASICS S4+ Yogiri sits in an awkward price spot. On one hand, you can find shoes like the Saucony Endorphin Speed 5 that are faster and cost less. On the other hand, if you specifically want a race-oriented shoe with a carbon plate, this is the cheapest option right now. Most carbon-plated shoes are either much more expensive or designed mainly as super trainers, which can make the S4+ Yogiri even look affordable.

But if we have to pick a side, we’d say it leans expensive. In a racing shoe, energy return should be a key factor, and here it falls short.

The heel closely mirrors the Metaspeed series design and skips a heel tab, but it adds a bit more structure, which results in better heel support overall.