Nike Structure 25 review

We recommend the Nike Structure 25 as an excellent choice for: 

• Overpronating runners who want a comfy yet stable daily trainer that rides like a neutral shoe
• Heel strikers in the market for a responsive and well-cushioned road shoe that's versatile enough to tackle recovery runs as well as long-distance efforts.
• Broad-footed runners who need a toebox with some added internal real estate
• Runners in colder climates looking for a warm shoe that performs consistently no matter how low temperatures drop

While stated to have a 10 mm heel drop, we found the Structure 25 to have an even steeper offset of 12.1 mm. While this is conducive for heel strikers and those with lower leg issues, we recommend that those with a forefoot striking stride go for a shoe with a lower drop like like the Hoka Arahi 6. 

The Structure 25's toebox may prove to be a little too roomy for those with narrow feet. We recommend either sizing down slightly for a more snug fit or looking at a less spacious alternative like the ASICS Gel Kayano 30. 

While its Cushlon 3.0 midsole feels quite responsive underfoot, we found that the Structure 25 lacks the energy return and is a little too heavy to facilitate speedier runs. The Saucony Tempus feels snappier underfoot and is better suited for high-paced sessions. 

Although the Structure 25 does boast a fair amount of airflow, its generous padding and dense upper mesh mean that it feels quite toasty on warmer days. For a more breezy alternative that doesn't turn into a sweatbox as the mercury rises, we recommend checking out the Brooks Adrenaline GTS 23 instead. 

Using our calliper, we measured the Structure 25's stack to be 36.7 mm thick at the heel which makes the 37 mm stated by Nike quite accurate. We like to see that here in the lab. 

Having this amount of foam underfoot isn't just good for heel strikers, but is suitable in general for long distances where most runners tend to revert to heel landings as fatigue sets in. Furthermore, it really allows us to sink into and savour Nike's Cushlon 3.0 midsole foam during our test runs. 

Nike wasn't as accurate with their forefoot stack measurement of 27 mm as we found that there is actually only 24.6 mm of foam in that part of the midsole according to our calliper. 

This is still an average amount of foam at the forefoot for a road shoe and means that we enjoyed comfy forefoot landings as well while testing this shoe. 

The discrepancy with the forefoot measurement means that the Structure 25 has a heel drop of 12.1 mm as opposed to the 10 mm as stated by Nike. This isn't totally out of the norm for us here in the lab as we've come across many similar deviations while testing shoes as explored in this article. Nevertheless, this still puts the Structure 25 in the category of high-drop shoes that tend to favour runners with a heel-striking stride or those with calf or lower leg issues as it puts more load on our hips and knees.

While we believe that midfoot strikers should still get some benefit out of this shoe, this steep offset means that forefoot strikers won't be able to appreciate all the Structure 25 has to offer. For those runners, we recommend going for a shoe with a lower drop like the Saucony Tempus (8.5 mm) or the Hoka Arahi 6 (4.1 mm) instead. 

One thing we love about the Structure 25 is its comfy yet supportive ride that doesn't feel like your typical stability shoe. It pampers our feet in the right ways while subtly guiding us towards a more neutral stride. What's more, it feels great out of the box but ages like a fine wine and feels even better after a few runs. 

Pressing our durometer against the Cushlon 3.0 midsole gives us quite a plush reading of 17 HA.  When combined with the shoe's robust stack, this explains the soft and pillowy landings we enjoyed while testing the Structure 25.

However, the Air Zoom unit embedded in the forefoot means that the midsole doesn't feel as cushy in this part of the shoe, with the trade-off being a little extra pep to our toe-offs. It's not crazy springy but it was a welcome amount of energy return during our longer runs. 

We placed the Structure 25 in our freezer to observe the effects of cold conditions on the midsole. 

After twenty minutes of chilling, we pressed our durometer against the Cushlon 3.0 once more and found that it only got 17.6% firmer. This is quite consistent compared to our current lab average and, with a post-freezer reading of 20 HA, the Structure 25 should still feel comfy and forgiving underfoot no matter how cold it gets. 

At 5 mm thick according to our caliper measurements, the Structure 25's insole is ever so slightly thicker than our current lab average. This gives us a nice and soft footbed to land in before the midsole cushioning even kicks in. 

The Structure 25 boasts a roomy toebox that we measured to be 100.4 mm wide at its widest point. This makes it broader than our current lab average which means that it should provide an accommodating fit for most runners, even those with broad feet. 

On the other hand, runners with narrow feet may find that they have a little too much room in the forefoot to achieve a secure lockdown. However, since we found the Structure 25 to be a little long for a men's US size 9 compared to our lab average, we suggest that those runners try sizing down for a better fit. Alternatively, the ASICS Gel Kayano 30 comes with a more snug toebox that won't feel so spacious. 

Moving up to the area around the big toe, the Structure 25's toebox is 77.4 mm wide according to our caliper. This is on par with our current lab average and means that we had plenty of room to splay out comfortably during our test runs. However, those with certain foot shapes or very broad feet should look into the shoe's extra wide option to avoid developing hotspots or blisters. 

The Structure 25's outsole isn't as robust as our current lab average at only 2.3 mm thick according to our calliper measurements.

This, along with the decision to go for incomplete coverage of the midsole, is surely a decision made with shedding weight off the shoe. 

Incredibly for a shoe that doesn't use any rigid medial posts or shanks in its construction, the Structure 25 manages to feel incredibly stable underfoot as it gently nudges us towards a more neutral gait. We'll explore the factors that play into this steady ride over the next few tests. 

We found the Structure 25 to be quite difficult to bend and twist manually, leading us to give it a subjective torsional rigidity score of 4 out of 5. As such, the shoe is able to maintain a nice and level landing surface by resisting any excessive lateral movements of our foot. 

The heel counter is also quite stiff, earning another score of 4 out of 5 in our manual assessment.

This strong structure in combination with the generous amount of padding back there presents a good balance of stability and comfort as it locks our rearfoot in place and mitigates rolling without putting too much on our heels or tendons. 

Another big factor in the Structure 25's well-balanced ride is its broad base. Using our caliper, we measured its midsole to be 116.4 mm wide at the forefoot which is quite a bit wider than average. 

At 95.3 mm wide according to our caliper measurements, the midsole is even wider at the heel when compared to our lab average. This gives heel strikers a robust landing platform that will surely keep them feeling surefooted with every stride. 

Despite its relatively high level of torsional rigidity, we discovered that the Structure 25 is quite pliable in a longitudinal sense. After securing it to our workbench by the forefoot, we used a force gauge to bend the shoe and found that 22.1N of force is required to get it to 90 degrees. 

This result makes the Structure 25 more flexible than the average road shoe and means that it's able to conform to the flexion of our foot with relative ease. 

We also repeated our flex test after leaving the shoe in the freezer for twenty minutes and found that it only became 16.7% stiffer when exposed to the cold. This not only makes the Structure 25 much more consistent than the average shoe under similar conditions but, with only 25.8N of force needed to bend the shoe to the desired point, it's more flexible than most shoes at room temperature! Taking this into consideration along with the midsole's post-freezer performance and the shoe's toasty upper, we conclude that the Structure 25 will make a great year-round companion no matter how frosty it gets in the winter. 

In spite of the aforementioned weight-saving measure, the Structure 25 still tips our scale at a heavier-than-average 10.7 oz (302g). However, this is still on par with the average stability shoes and doesn't feel overly burdensome underfoot, especially when it comes to easier paces. 

To test the breathability of the shoe, we pumped the Structure 25 full of smoke to see how easily it vents through the upper. As the footage demonstrates, it takes quite a long while before any smoke is able to filter out of the shoe. Eventually, a light haze emerges and flows steadily, albeit in rather thin wisps, throughout the shoe. This leads us to give the Structure a middle-of-the-road score of 3 out of 5 for breathability. This is, no doubt, thanks in part to the generous amount of thick padding throughout the shoe which does feel quite warm as we take the shoe for test runs. 

The Saucony Triumph 20, on the other hand, blew out billows of smoke that earns it a perfect score in this test. 

However, how easily the light shines through a backlit cross-section of the shoe's upper over a backlight would lead us to believe otherwise as we've found that this is usually an indicator of good breathability. 

Our microscope lays our questions to rest as it reveals how densely woven the Structure 25's multi-layered upper mesh is. We only see very small visible gaps in between the braids that go all the way through and promote some level of airflow. This explains the smoke's delayed ability to start filtering out of the shoe in our first assessment. 

To simulate extreme wear and tear, we fired up our Dremel to 5K RPM and set it against the Structure 25's toebox with 3.2N of force. 

After four seconds of grinding, we found that our tool had an insignificant effect on the shoe's mesh as the damage left behind is barely noticeable. This stellar performance leads us to give the Structure 25 a toebox durability of 5 out of 5. 

The heel collar proved to be almost as hardy as the toebox in its face off against our Dremel. 

While our tool was able to menace the lining to a certain extent, it wasn't able to pierce through it and reach the soft padding within. As such, we give the Structure 25 a heel padding durability score of 4 out of 5. This is excellent for a daily trainer and means that no amount of heel rubbing, even when going sockless, will significantly compromise the shoe's comfort or lockdown at the rearfoot. 

Pressing our durometer against the Structure 25's outsole yields a reading of 88.5 HC. This is quite a bit harder than our current lab average which bodes well regarding the outsole's longevity.  

Now spinning at 10K RPM, we set our Dremel against the outsole for a grand total of twenty-two seconds of abrasive force. 

Afterward, we used a tyre tread gauge to measure the indentation left behind in the wake of the test and found that 0.8 mm of rubber had been worn away. This isn't quite as durable as we had anticipated based on the hardness of the rubber but still puts the Structure 25 on par with our current lab average. We therefore expect this shoe to last the expected shelf life of 400 to 500 miles before any significant signs of wear and tear appear. 

The Structure 25's outsole isn't as robust as our current lab average at only 2.3 mm thick according to our calliper measurements.

This, along with the decision to go for incomplete coverage of the midsole, is surely a decision made with shedding weight off the shoe. 

We had no complaints with the outsole grip while testing the Structure 25 over the normal surface we expect to come across when road running. Even a smattering of rain that left the asphalt wet was no cause for hesitation during our runs in this shoe. 

The Structure 25 features a small reflective streak at the heel that provides some, albeit minimal, nighttime visibility. We still recommend using additional high-vis gear whenever taking this shoe out for a nocturnal romp. 

At 11.8 mm thick according to our caliper measurements, the Structure 25's tongue is much beefier than our current lab average. As such, we experienced an incredibly luxurious lockdown once we were laced up and ready to go, with the laces themselves sinking into the pillowy tongue and virtually disappearing from our consciousness. 

Despite being non-gusseted, we didn't experience any issues with the tongue slipping from side to side as we tested the Structure 25.

This is thanks to its chunky nature and the long central lace loop that helps mitigate slippage.

The Structure 25's insole is easily removed so it can easily be replaced with an after-market alternative or a custom orthotic for added arch support if necessary.