Adidas Solarboost 5 review

We believe the fifth update of the Solarboost is a solid pick for:

• Fans of the Solarboost saga that seek a similar running experience but improved, with a lighter build and better stability.
• Runners in search of a workhorse for eating miles that prefer a firm feel underfoot.
• Heel strikers who dislike maximalist designs and prefer a moderately cushioned shoe that still guarantees protection underfoot.

After extensively running and testing the Solarboost 5 in the lab, we found that its cushioning may be too firm for those who prefer a plush midsole. If that's you, we recommend checking the ASICS Nimbus 26 or the Nike Vomero 17 instead.

We also advise against getting the SB5 if weight is a major concern. Despite being lighter than previous generations, we found it still hefty, and we recommend alternatives like the Brooks Ghost 15 or the Hoka Clifton 9.

The heel boasts a 32.9 mm stack height, positioning the Solarboost away from maximalist competitors and providing a well-cushioned experience without reaching skyscraper heights.

We believe this is sufficient because the foam isn't overly plush, ensuring that even the heaviest runners won't bottom out the Light Boost.

The forefoot feels a bit too thin for a modern long-distance shoe, which is why we recommend this model particularly for short to medium efforts up to 15K at comfortable paces. For longer distances, we believe a more cushioned option like the ASICS Novablast 4 might be a better choice.

The official drop of the Solarboost 5 is listed at 10.0 mm, but our measurements show a slight variance, clocking in at 9.8 mm. However, this precision is truly impressive.

Furthermore, like most Adidas training shoes, it suits those who prefer higher offsets, particularly heel strikers.

We've already touched on the midsole changes in this lab review, particularly the transition from Boost to Light Boost. Yet, there's more to discuss beyond just the reduction in weight.

A key aspect of Light Boost is its high density. Despite being lighter than Boost, it's still relatively heavy and provides a firm ride.

We measured it at 33.5 HA using our Shore A durometer. This indicates that the shoe may not suit every runner—it's best for those who prefer a more traditional, firm feel underfoot.

And how does the Solarboost 5 foam perform in cold temperatures? It excels, thanks to two key advantages. Firstly, it's a firm shoe; secondly, it uses Light Boost, not EVA—which tends to underperform in the cold—but TPU.

These factors combined meant that after spending 20 minutes in our freezer, the SB5 only became 1.9% firmer, showcasing its impressive resistance to cold weather.

The footbed, crafted from EVA foam, features an ample thickness measuring at 5.7 mm, providing substantial comfort underfoot.

Our initial measurement in the toebox focused on the widest part of the upper—a critical aspect for many runners, especially those with wider feet.

Fortunately, we've confirmed that this shoe accommodates broader feet exceptionally well thanks to its 100.2 mm of width.

In our second toebox measurement, we focused on the big toe area, crucial for assessing tapering.

We discovered a wider-than-average toebox, providing ample space for various toe shapes with our 80.7-mm measurement. However, individuals with narrow feet might prefer a narrower option like the Hoka Clifton 9.

From our first run, we found the Solarboost 5 to be exceptionally stable for a daily trainer. It was only when we took a closer look that we appreciated the extensive effort the German brand has invested in stability—clearly, it’s the main selling point of this model for us.

Several features contribute to the Solarboost's remarkable stability, which we'll detail in this review.

The most obvious, at least visually, is the light orange EVA structure encircling the heel and extending to the midfoot. Adidas has named this the Control Platform, which effectively guides the foot and prevents excessive lateral movement.

Another key stability feature is named the Linear Energy Push (L.E.P). Positioned between the foam and the outsole, it adds extra torsional rigidity, further enhancing stability.

We just touched on torsional rigidity, so let's dive into that. After twisting the shoe, we believe it earns a 3/5—a balanced rating for a daily trainer.

The heel counter also earned a 3/5 from us, landing squarely in the average range. It strikes a balance between stiffness and softness, indicating that Adidas aimed to enhance stability without compromising comfort.

Here we encounter another significant factor contributing to the overall stability of the Solarboost 5.

Measuring 117.0 mm across the forefoot, its dimensions are on par with many stability shoes. We discovered that it provides a wide landing platform, offering exceptional stability with every step.

Having a high drop, this shoe is perfect for heel strikers—we expected a wider platform compared to the forefoot. Our assumption was that the heel area would significantly outsize the average shoe in this aspect.

We once again used our digital callipers and discovered that the heel measures at 98.3mm. This measurement is indeed quite wide, easily surpassing most daily trainers by a noticeable margin. From our perspective, this broad base provides substantial stability and support.

One of our initial concerns about the Solarboost 5 was its potential stiffness because of its torsion enhancement system and the firm foam used. However, during our first run, we were pleasantly surprised. We quickly discovered that the Solarboost 5 was not stiff at all, but rather quite the opposite!

After testing it on the roads, we conducted the 90-degree bend test to confirm our initial impression. We fixed the shoe and bent it to the specified angle. The result was a force measurement of 21.3N, indicating that the shoe is indeed very flexible.

Just like with the midsole softness, our subsequent cold-weather test delivered world-class results. After spending another 20 minutes in the freezer, the shoe only became 4% stiffer—this is truly remarkable!

The Solarboost series has consistently been on the heavier side, primarily because—as we detailed in our ultimate guide on running shoe foams—Boost is really heavy.

However, the v5 has made a significant shift to Light Boost, a newer version of the original that retains the same cushioning qualities while cutting down 30% of the weight. This change brings the Solarboost 5 down to a more manageable 10.3 oz or 293g.

While this weight is not excessively heavy, it's still a bit hefty for its size, and needs further improvements.

Our initial impressions of the Solarboost 5 were underwhelming—our smoke test showed limited breathability, earning the mesh upper a mere 2/5 rating.

We used a powerful light to explore the upper's structure and discovered some interesting features. It's evident that Adidas focused on comfort and stability, as the medial zones are well-built. However, the toebox, despite being thin, lacks sufficient breathability.

To further investigate the toebox, we utilised a microscope, which proved ideal for this analysis.

We discovered that, although there are ventilation spots, the multi-layer design restricts air flow. Additionally, we noted that Adidas reinforced the mesh to enhance durability—a feature we'll challenge in our upcoming test.

Overall, the shoe offers excellent comfort, but this comes at the expense of ventilation.

Therefore, we do not recommend the Solarboost 5 for summer use—it's better suited for cooler seasons.

We previously hinted that we were gearing up to test the upper's durability, and now we're here, setting up the Dremel for that very task.

From our tests, it's clear that Adidas's strategy has really paid off. While it may not be the most breathable upper we've ever seen, the toebox certainly exhibits better-than-average durability at 3/5.

We've already established that the toebox offers impressive durability, but we also wanted to examine the heel padding—an area that concerns many runners.

For the second time, we revved up the Dremel and really pushed the Solarboost 5 to its limits. We found that the resilience in this area is simply outstanding, easily earning a perfect score of 5/5 from our team in the lab.

Adidas is well-known for crafting outsoles that provide excellent grip, even when using hard compounds, and this shoe is no exception—it clings like claws. We measured the outsole at 88.6 HC, but there's more to its performance and design.

In this model, Adidas has opted for a main material known as Crystal Rubber, which features dozens of mini-lugs that enhance grip. Additionally, it's boosted by a small strip of Continental rubber in the forefoot. Although we might have preferred a fully Continental outsole, we discovered that the current configuration also offers outstanding traction.

The Crystal Rubber outsole may grip like sandpaper, but is it built to last? To answer this, we fired up the Dremel for a third and final test in our lab review.

After examining the results, we were taken aback by a significant issue. Typically, outsoles with mini-lugs suffer in durability due to their configuration—our findings confirmed our concerns.

We discovered a 2.5-mm indentation, which suggests that outsole durability could be a major problem with this shoe, particularly for heavier runners.

Our final assessment of the outsole involved measuring its thickness with our vernier callipers, which showed just 2.0 mm. However, it's important to consider that this measurement doesn't include the mini-lugs.

Adidas is notorious in our lab for neglecting reflective features, and sadly, the Solarboost 5 follows suit.

The tongue boasts exceptional padding—a main pillow-like foam flanked by two thinner layers.

Altogether, we measured it at 10.2 mm of thickness, ideal for those prioritising instep comfort!

The fully gusseted tongue is a delightful surprise, especially since mid-tier running shoes often lack this feature. It's a generous touch from Adidas—making the Solarboost 5 even more appealing to us.

While the Solarboost 5 lacks a heel tab like the Adizero series' flap in the Adios Pro 3, we discovered an extended heel collar. It eases Achilles tendon pressure and aids slipping feet into the shoe.

The insole easily removes—it's not glued—giving flexibility for custom footbeds. Plus, it's a 100% standard shape, so you can pair Solarboost with any third-party option.