ASICS Solution Speed FF 4 review

We think that the Solution Speed FF 4 may be right up your alley if:

• you need a speed-oriented tennis shoe that doesn't compromise cushioning
• you want durability and support in a lightweight package 
• you prioritise tacky grip on hard court

The added cushioning of this ASICS shoe may not appeal to shifty players who prefer to stay as close to the court as possible. You can find a much more grounded setup in the adidas Adizero Ubersonic 5.

And if you play long matches in warm weather and want to avoid sweaty feet, we'd rather go for the adidas Adizero Ubersonic 2 as a more breathable option.

Added cushioning is one of the most notable updates in the Solution Speed FF 4. Our lab test showed a 9% increase in the new version's shock absorption at 113 SA in the heel and 67 SA in the forefoot.

With its thicker and softer FlyteFoam midsole, the FF 4 shifts away from the grounded feel of the FF 3, earning a spot among the best cushioned tennis shoes in our lab!

The brand's product description also promises 'a high-energy return' with the new FlyteFoam in the FF 4.

Fact-checking that claim in our lab, we found that the shoe indeed offers 10% more energy return than its predecessor! But here is the kicker: it still falls below the category average at 44% in the heel and 42.4% in the forefoot.

Even though there is a little more life in the FF 4's midsole, it still feels relatively flat and lacks bounce compared to most other tennis shoes. Yet this translates to a more predictable and controlled ride.

But that added impact protection didn't come out of nowhere. Our calliper recorded that the FF 4's stack height increased by a few millimetres, reaching 30.9 mm in the heel.

That makes this ASICS shoe a smidge taller than average, matching the ASICS Gel Resolution X's stack height.

We also recorded an additional millimetre of foam in the shoe's forefoot. But at 19.9 mm, it remains a bit more grounded and on par with the average.

Despite the changes in its stack heights, the heel-to-toe drop of the Solution Speed FF 4 remained at 11.0 mm.

A common offset for tennis shoes, it adds cushioning in the heel and minimises strain on the Achilles and calves.

True to the brand's product description, the Solution Speed FF 4 indeed uses a softer FlyteFoam cushioning.

Pressing a durometer against it returned a lower reading of 38.6 AC, which is a good 18% softer than the FF 3's midsole!

It also happens to be one of the softest tennis shoe foams in our lab, close to the Fresh Foam in the New Balance X CT-Rally v2 (34.6 AC).

We couldn't help but notice some changes in the Solution Speed FF 4's fit.

Measuring the dimensions of its one-to-one gel cast with a calliper, we recorded an unusually wide reading of 97.5 mm in the ball-of-the-foot area. This is a major step away from the snug, one-to-one fit of the FF 3!

But on the other hand, the shoe's toebox remains tapered. Even though it got a few millimetres wider in the big toe area, it stayed on par with the category average at 69.1 mm.

However, the shoe's toebox can feel restrictive because of its shallow vertical space. At just 20.6 mm, it is one of the lowest toeboxes among tennis shoes.

This makes the Solution Speed FF 4's fit a bit unconventional and confusing for some players, but ordering half a size bigger seems to have solved the problem for most people.

Featuring the brand's premium ASICSGRIP outsole rubber, the Solution Speed FF 4 showed us what tacky really means!

With a whopping friction coefficient of 1.11, the shoe offers unmatched traction on hard cuts, push-offs, and quick stops. It is the kind of traction we can trust at full speed without hesitation!

Examining the bottom of the shoe, we found an updated basketweave Precision Sole and the familiar split-sole design as in the FF 3.

Separate heel and forefoot sections with deep flex grooves provide grip where it matters while helping the shoe stay light and flexible enough for speed and manoeuvrability.

The Solution Speed FF 4 remained just as flexible as the previous version, requiring slightly less force to bend (15.8N) than the average tennis shoe.

That pliability makes footwork feel a bit more natural in this ASICS shoe, making adjustment steps, recovery steps, and repositioning less cumbersome.

The Solution Speed FF 4 couldn't get away with adding more cushioning without also gaining weight.

But even with an extra ounce, the shoe still weighs lighter than average at 11.9 oz (337g), staying in the speed-oriented range.

And it is significantly lighter than the other high-performance shoes from ASICS, the Court FF 3 (14.3 oz) and the Gel Resolution X (14.7 oz).

Unfortunately, breathability took a major hit in the new Solution Speed FF. At only 53 BR, it showed one of the lowest results in the tennis shoe category.

Whether it's the new upper textile, the thicker in-shoe padding, or something else, the FF 4's materials really struggle to pull sweat away from the skin. And as a result, you end up at high risk of clammy feet and blisters, especially in warm weather.

On top of that, our lab test also showed that this ASICS shoe evaporates moisture too slowly. After keeping it on a heated footform inside a climate-controlled chamber for 3 hours, we recorded that the shoe released only 34% of the artificial sweat.

This means that on longer matches, accumulated sweat becomes an even bigger problem as trapped moisture starts leaking back into the socks.

Its added stack and softer midsole foam raised concerns about whether the ASICS Solution Speed FF 4 can provide the same level of stability we've come to expect from the series.

And to our relief, it can!

Sure, it's nowhere near as planted and supportive as the Resolution, but it packs the essentials you need in a speed shoe that 'supports fast and dynamic motions,' as the brand promised.

First of all, the FF 4 carries over the sturdy Speedtruss shank that holds the midfoot in a secure clutch, providing solid structure that resists twisting.

Our torsional rigidity test confirmed that it takes an above-average torque of 19.9 Nm to twist this ASICS shoe by 10 degrees in both directions.

The shoe's heel counter also showed some serious resistance to our manual pushing and squeezing, earning a high stiffness score of 4.

Experiencing no shifting or wobbling, we found that it cups the heel and ankle very well during intense movement.

We also noticed that the Solution Speed FF 4 received a slightly wider platform, apparently to balance out the shoe's thicker and softer midsole.

Our calliper showed that the shoe's forefoot grew by as much as 5.4 mm, reaching 111.9 mm in the broadest area.

As for the heel, it remained practically unchanged, measuring 88.6 mm at its widest point.

Remarkable durability was one of the Solution Speed FF 3's strongest points, and the same holds true for the new FF 4.

The shoe's medial side is reinforced with a tough PU toe drag guard, which proved its wear resistance in our Dremel test, earning a high score of 4 out of 5.

A piece of the same PU material also forms two eyelets at the top of the shoe's medial side. It is a small but amazingly thoughtful feature that protects laces from tearing.

But it's not just the shoe's reinforced areas that show excellent durability; its exposed textile can take a beating, too!

After applying our Dremel to the material on top of the shoe's toebox for 12 seconds, we were impressed by how minimal the damage was! That earned it a high durability score of 4 out of 5.

The mesh lining inside the shoe's collar showed no impressive wear resistance, but it didn't get destroyed either. That settled its durability score at 3 out of 5.

The AHARPLUS outsole showed unbeatable durability in the FF 3, and the new ASICSGRIP rubber on the Solution Speed FF 4 proved every bit as durable!

With barely noticeable damage of 0.5 mm, it is one of the most hard-wearing blends we've encountered!

Even the fact that its outsole is thinner than average at 3.0 mm doesn't make us doubt that this ASICS shoe can withstand some serious abuse.

The shoe's moulded Ortholite insole is adequately padded, with a thickness of 5.0 mm at the heel.

It is also easily removable in case a custom orthotic is preferred. But given the shoe's extremely low toebox height, we can't be sure if it fits most orthotics.

The padding got notably beefier in the Solution Speed FF 4, and our calliper measured its tongue thickness at an above-average 11.5 mm. This is also a few millimetres thicker than the FF 3, offering even more buffer from lace bites.

We were happy to see that the tongue received partial gussets in the Solution Speed FF 4! This is a big plus for lockdown, keeping the tongue securely in place during active side-to-side movements.

There are no finger loops to help with the on-and-off in this ASICS shoe.

With a tangible £20 price hike, the ASICS Solution Speed FF 4 lands among the premium tennis shoe options. But as a high-performance shoe with standout cushioning, traction, and durability, we believe that it justifies the price tag.