On Cloud X Review
Cons: Outsole picks up rocks and gravel, toebox can be too flexible, tongue can rub
Manufacturer: On Footwear
Our Analysis and Test Results
Speedy and fly, the Cloud X is among the latest offerings from On's Performance selection. On notes in its description of the model that the comfort is not apparent on first look, but they're right in asserting that it can be felt. It's all in the sculpted form-fit, smooth lining, and firm foam padding along the collar. Their new tongue is seamless, drastically improving on the models from its popular active selection. The sockliner covers the entirety of the shoe, offering a layer of cushion throughout, making for a much more comfortable ride. They combine a narrow neck and low profile to cradle the foot for support and control without sacrificing speed and agility. Read on to see how they do against other top models in each of our measures.
On hit upon a solution to racing flat responsiveness that is unique in the running shoe industry. Responsiveness typically requires a good deal of foam or another firm, springy material. However, this can compromise the flexibility and quick feel characteristic of racing flats, not to mention add weight and bulk. To balance this out, On developed their CloudTec midsole, made up of hollow EVA cuboids, which are called Cloud Elements.
The Cloud X uses a stronger speed board in its sole, which peps up its responsiveness enough to noticeably reduce the sink on strike and add a little more return at toe-off. This excellent give and return tops the baseline Cloud model whose Cloud Element midsole also delivered excellent response, but didn't quite have the same stiffness to charge as hard as the X. The X's innovative Cloud Element midsole, stiff speed board, and gripping fit turn out a racing flat with superior responsiveness.
Landing comfort is an area where these shoes perform really well, at the very top of our fleet. This is due, in large part, to the CloudTec midsole with its EVA Cloud Elements. At first, the articulation of the pods under the forefoot and toes of the Cloud X can distract or feel unstable, but after a few minutes, that dissipates, and you adjust to the unique landing and come to appreciate what it's doing for your stride. What's remarkable about these trainers is that they don't sacrifice responsiveness by offering their high degree of landing comfort. That's largely owed to their use of a new, more rigid speed board that helps provide the return and the tough, reflexive pods whose hollowness allows for a natural-feeling compression and kick-back.
These come in at 17.8 ounces in men's 11, slightly more than their Cloud cousins in the Active lineup. This is owed to a little more padding in the upper, the added speed board, and a full-length sockliner. Despite the extra weight, they are still objectively very light, and on a slightly less objective note, they still feel fast. This is another area where their crazy design is also surprisingly functional. The sole kicks out a good deal of responsiveness and lays out perfect cushion without needing to throw in slabs of foam.
The high performance X improves on some of the other popular On models by removing damage liabilities like the decorative heel strap and narrowing the openings around its Cloud Elements, improving the longevity of the shoe. It still has the vulnerabilities you would expect in any lightweight, high-performance racing flat; its mesh is thin and might wear down faster than clunkier models, its light outsole might wear faster with its accurate placement of tough carbon rubber, and its finer features like the smooth sockliner and padding could break down faster than is desirable.
Durability isn't typically a category dominated by lightweight racing flats, so the X didn't score particularly high here. The models that excel in this metric are the tank-like designs with tons of tough rubber on their outsole, coarse upper mesh, and reinforced superstructures. They top out the measure and might last for years and withstand all sorts of physical abuse, but they aren't going to be speedy or flashy.
Our favorite feature of the Cloud X is the smooth, seamless sockliner throughout the upper. This makes a huge difference after the endorphins wear off from the first few miles, and the rubbing and chafe starts to set in. The toe box is nice and roomy, but the laces also lockdown for a snug ride if so desired. The sleek vamp (front and sides) and streamlined quarter (heel cup area) feel more like a velvety, reinforced canvas, allowing more freedom of movement than might be seen in sturdier models.
Balancing comfort with breathability can be difficult, but this shoe navigates it well. Comfort often comes in the form of padding and sockliners, and breathability often comes in the form of limited padding and thinner sockliners with less coverage. The Cloud X uses firm foam padding that allows the heel to air out without hugging too tightly and overheating or holding moisture. The liner along the vamp tends to hold a bit more moisture than is ideal, but the wide gauged upper mesh does help wick away some of the excess heat and damp collected by the felt-like liner.
These come at a bit of a premium, but we think their price is a fair ask. They superbly balance response, comfort, and weight to create a fantastically unique product that many runners will be delighted to own.
The Cloud X earns one of the highest scores for a reason. The theme we have to keep returning to is balance. The X is a masterpiece of balance. It offers the right mix of cushioning, breathability, style, weight, stability, and speedy-feel to keep us reaching for them when it came time to go out for the elective runs. Keep in mind this is a high-performance model, and you're paying for that quality. If you're looking for something to beat up and take out in the rain and mixed terrain, you might want to move down the spectrum a bit and keep these on the top shelf for race day and lead-up training.
— Ryan Baham