Review: On Running Cloudboom Strike LS

Many people swear by barefoot running, and look, there is a bunch of evidence that says maybe they’re right. But I am not one of those people, mostly because I lack the discipline to attune my body to its natural affinity for moving quickly on bare feet. No, I want a big ol’ sole that feels nice and squishy. I want shoes I can sink into and that add a bounce to my step.

“If you start buying shoes based on comfort instead of style, that means you’re old now,” a friend told me recently. Fine, that’s part of it. But also when I was a kid I watched an episode of the cartoon Arthur where the animal/human hybrid children get moon boots that let them bounce around everywhere. That’s all I’ve ever wanted shoes to do for me since.

Enter On Running’s new shoe.

Foam Party

Usually, shoes with big fat soles feel clunky on your feet. To gain all that squishiness beneath your heels, there is a trade-off in the extra weight that comes with pushin’ that cushion. On Running wants to cut out every bit of that excess weight with an innovation it calls LightSpray technology. This is a 3D printing technique in which a robot arm creates an entire shoe upper by spraying out a steady stream of foamy plastics. The whole process takes roughly three minutes, which you can watch in the company’s incredibly satisfying video.

Photograph: On Running

The robot arm carefully crafts the “computer-optimized outsole” by using a material that the company calls Double Helion™ HF hyper foam. On says the foam is made up of over 40 percent bio-based plastics. It works like this: The robot arm sprays the foam onto a mold. The material congeals and retains the shape of the shoe, all in one solid piece. Then you can slip it on. The final shape stretches to accommodate your foot—no lacing required, no added weight up top.

The first shoe to utilize this ethereal spray-on technology is the CloudBoom Strike LS. It is modeled after On’s CloudBoom Strike marathon shoes and is meant for high performers and elite marathon runners. One Strike LS weighs 170 grams (6 ounces), which is about an ounce lighter than comparable shoes like the Nike Vapourfly ($260). They feel very light indeed, but they also cost $70 more and aren't available yet. On says there will be a limited release later this year.

More Bounces for Less Ounces

If you like springy cushions on your shoes, running in these feels wonderful. I’ve taken them across pavement, trails, and sandy beaches, and every time they hold up well and feel great while providing a sublime feeling of a bounce in your step. The tightish seal around the ankles even does a stellar job at keeping dirt and sand out of the toe box. They’re weirdly breathable too, and the toe box doesn’t feel overly grippy or clingy. I have had no trouble keeping them on, either. Even sans laces, they fit snug. Though it may look and be built quite different, it still feels like a very good running shoe.

Photograph: Boone Ashworth

Shoes from On have a very particular look—some might call it “unapologetically garish” or “proudly goofy.” The CloudBoom Strike LS follows that eccentric lineage, though to an even greater extent. With their single-piece upper toe box, they look very different than just about any other shoe. Fashion-wise, they wind up looking like whatever socks you’re wearing, because the upper box is translucent when it wraps around your foot. (Wear the shoes without socks and everyone will see your steamy digits wriggling around in there.)

You should wear socks, particularly long ones. When I wear shorter socks that don’t go up past the ankle, the edge of the hole in the upper shoebox can chafe against my fibula—aka the outer lower leg bone that ends in a roundish nub at the ankle. (No, I didn’t have to Google that. You had to Google that.) It wasn’t horrible, except during one run in shorter socks when it rubbed a raw spot in my skin. Just wear longer socks and that problem goes away.

The tricky part is putting them on your feet in the first place. The sprayed-on upper sits at the top of the shoe in one complete piece, with a narrow hole you’re meant to stuff your feet into. The stretchiness of that opening is tighter than something like elastic, so it can take a bit to actually get your whole foot through. The membrane feels very thin but holds together, for the most part. Except, of course, if you are in a hurry and try to get your foot in there too quickly.

Photograph: Boone Ashworth

I tore the top of the Strike LS because I was wearing a slightly thicker pair of socks than normal and was struggling to put them on. I had my toes in, and in the attempt to get the rest of my foot in there, I pushed a little too hard while holding the sprayed-on membrane. The bit I was holding tore. It was the fourth time I’d ever put them on. Oops.

It is generally not a good sign when a product breaks after four uses, especially not when that product costs more than $330. (That’s roughly $82 per run.) But I should note that even after that, I have run in the CloudBoom Strikes for about two months and put more than 100 cumulative miles on them. In all that time and wear, that little tear is basically the exact same size. The bioplastic holds its form and hasn’t ripped further or affected the fit when I run in them. A rip isn’t ideal, and perhaps something bigger might have caused real problems, but in my experience On’s material holds. It just means I felt the need to be a lot more careful putting them on than with normie shoes.

Companies have certainly been pushing this laceless shoe thing. For instance, Nike’s $350 self-lacing Adapt BB could be controlled by an app that has since been shut down. The question, really, is whether the extra 15 seconds you save every day by not tying your laces warrants the extra cost and careful attention.

Elite Athletes Only

The CloudBoom Strike LS are very, very good shoes. They are cool, comfy, and also technical marvels, and all that visionary scientific endeavor is laudable. (Go watch that video again. It’s neat!) Their potential environmental impact is worth remarking on, too. You can probably find more environmentally friendly running shoes, like those made from algae, but On’s additive process for constructing these kicks has the potential to be much more efficient than standard shoe manufacturing—no leftover fabric scraps to toss in the trash.

Photograph: Boone Ashworth

Running in the CloudBoom Strikes is magnificent. They’re lighter than any shoe I’ve worn before, even many barefoot shoes, and they feel so squishy that I can almost fool myself into thinking I’m bouncing in my moon boots. But you know what else makes me feel like that? Other On shoes, and ones that cost considerably less money. If you're not an elite marathoner for whom every ounce counts, you get just as much squishiness out of On’s Cloud Monster, which, at $180, are nearly half the price of the sprayed-Ons. As a bonus, you don't have to treat them like delicate sponge cakes when you're shoving them on to head out on your run.

But boy, if you aren’t worried about the cost, you’ll enjoy these lightweight future shoes. They’re the lightest shoe you’re going to get with the amount of cushion they offer. Once you get them wiggled on, you’re going to have a hard time wanting to ever take them off.