Nike Delivers the Alphafly 4 Ahead of Fall Marathon Season. We’ve Tested It and Have the Deets

The most exciting thing about fall marathon season for me is the new shoes that get announced. Ahead of the World Marathon Majors, Nike has just announced the Alphafly 4, which has been a long time in the making—it’s been nearly three years since the last version was released. And, while Nike was taking its time to ensure it got everything dialed in for this new model, it ultimately fast-tracked the release because Nike athletes wanted to lace it up at this weekend’s World Athletics Road Running Championships in Copenhagen. (While prototypes are generally approved for competition, they aren’t permitted in World Athletics championship races.) We got a sample of Nike’s pinnacle carbon-plated racing shoe to give you the inside scoop on what’s new and what you’re going to love. When the shoe was leaked online earlier this month, the immediate reaction by runners was that this is basically the same as the Alphafly 3. To be fair, it does look similar and it’s not a revolutionary update, but there are promising differences. Nike claims the shoe is lighter, has more energy return and—maybe most important—it runs quieter. Let’s dive in. Nike has long maintained that Air units are the most responsive and resilient cushioning system, even outperforming all the new high-tech foams. And the Alphafly is still all about that Air, as you can see it’s featured prominently in the forefoot. In this update, however, Nike changed up how it builds those plastic, gas-filled bags to make them softer and lighter. Previously, Nike used heat to “thermoform” the units, Bret Schoolmeester, VP of running footwear product, said, when he briefed us on the shoe. But now it’s using RF Zoom Air, which stands for radio frequency—they’re using vibration and frequency to do what heat did before. What you should care about is that the new process makes the units 30 percent lighter and they boost cushioning underfoot. In my early trials of the shoe, I can see the blue Air unit squeezing laterally and poking out the side of the shoe as I stomp down on the forefoot. That’s not something I’ve found with previous iterations. And, on the run, it does make the forefoot feel a smidge smoother and more comfortable. Some of that smoothness could come from a reshaping of the forefoot rocker, which starts a little farther back—under the Air unit—and you can feel yourself easily falling forward. That said, the shoes still have some pop. I didn’t get them early enough to get in a quality workout but, on some postrun strides, they brought life back to my legs after a 90-mile week that included a 20-mile long run on Sunday. The ZoomX Foam Is Lighter, Too Just as Nike is sticking with the Air, it’s keeping the same Pebax compound it’s used previously, but this, too, gets tweaked. Schoolmeester said that making the foam is a lot like baking: All the same ingredients are there, but how you bake it can change the end result. In the case of the top layer of ZoomX LT foam, the baking process yielded a material that’s said to be 17 percent lighter but with 8 percent better energy return. This, folks, is where today’s shoes are headed—make them as lightweight as possible without sacrificing energy return and cushioning, because, as we well know, a heavier shoe requires you to use more energy over the course of your race. The Plate and Knit Are Mostly the Same The same scooped, spoon-shaped plate that Nike has used in previous versions carries over, but the plate is a little bit wider to help dial up forefoot stability. If you look at the pointy toe, you might think it looks awfully like the Puma Fast-R Nitro Elite 3. But that’s not what’s happening. The plate does extend nearly to the end of the shoe, though that little pointy bit of foam and rubber protruding off the tip is flexible and most definitely not carbon fiber like the Puma. The “nets,” or the overall width of the platform under your foot, has also been widened a bit. The combination of platform and plate lets you push hard into the foam without any wobble. In my runs, I had complete confidence rounding corners without slowing down. And the upper is still an exceptionally thin, see-through knit that Nike is calling Atomknit 2.0. It’s not radically different from Alphafly 3, but the most noticeable difference I can find is vertical banding along the sides of the shoe, which provides more security between the laces and the midsole. I can’t fully comment on the comfort and fit just yet, because my test pair is a half-size too big. I can make do with them okay enough, though I want them to be a bit more snug when I hit race pace. So I’ll report back after I get a pair in my normal size. Honestly, How Loud Are They? This might be the most pressing issue you want to know about. Previous versions of the Alphafly sounded like Clydesdale horses. A sea of marathoners clip-clopping down the road really is an astonishing racket. The AF3 also developed a really annoying squeak, where the foam and Air joined in the forefoot. Nike attempted to solve this, but it’s still going to be the loudest shoe on the racecourse, I’m sorry to report. I had a creaking noise in my right shoe less than a quarter-mile into my first run. That hasn’t let up after nearly 20 miles of use. And, because of the construction of the forefoot, the shoe still sounds like you’re a shod horse. It’s quieter, true, but it’s not quiet. Some of that squeaking, by the way, seems to come from the boatload of empty space around the Air units within the midsole. In AF3, I spread some bike chain lube in that space to get a temporary reprieve, and I might have to resort to that again with the Alphafly 4. When Can You Get a Pair? In order for Nike athletes to wear the shoes in Copenhagen, the Alphafly 4 has to be publicly available for sale. Nike is doing a limited release today at nike.com. So, yeah, good luck scoring a pair. Otherwise, you’re going to have to wait until October 29 to get a pair online or at select retail locations. Buy Men’s at Nike.com | Buy Women’s at Nike.com Jeff is Runner-in-Chief for Runner’s World and the director of product testing. He has tested and reviewed running shoes, GPS watches, headphones, apparel, and more for nearly two decades. He regularly tests more than 100 pairs of shoes each year, and once had a 257-day streak running in different models. Jeff can usually be found on the roads, racing anything from the mile to a marathon, but he also enjoys racing up mountains and on snowshoes. When he’s not running, you’ll probably find him hanging from a ladder making repairs and renovations to his house (he’s also director of product testing for Popular Mechanics).