Cloudflyer 4: complete analysis of a stable and firm shoe

The fourth generation of this On model operates in a very specific space: that of daily training shoes with support, a medium-firm feel, and construction cared for down to the last detail. It is not trying to please everyone, and that is precisely part of its personality. It offers a stable ride, a wide platform, and a comfortable upper, although in return it demands accepting a certain amount of weight and a price positioned at the higher end of the market.

Its approach works well for runners who prioritize security over softness, especially at easy paces, long runs, or sessions where control matters more than explosive response. It can also work off-road, as footwear for walking or daily use, because it combines a solid base with premium-looking materials and a fit that, in general, is less restrictive than one might expect from the Swiss brand.

What this model is really offering

On has built a moderately stable shoe here with a very recognizable philosophy: pronounced geometry, a relatively firm midsole, and a rolling sensation that does not sink under the runner’s weight. The recipe is not meant to replicate the softness of other brands, but rather to offer a clean transition and a structure that supports the foot without leaving it too free. That makes it a fairly logical option for those seeking control in a stride that tends to pronate or for runners who appreciate a base that does not twist easily.

In numerical terms, the whole package sits in the middle range among training shoes, but the feel tells another story. Its midsole is not soft: rather, it conveys a tempered firmness that, in real use, provides poise and a certain sense of discipline. The 9.8 mm drop and the rocker geometry help keep the transition from feeling clumsy, although the overall behavior still remains far from the buoyancy of the maximalist models that have gained so much prominence in recent years.

That character has very clear advantages and limitations. On the plus side, the stride feels orderly, the base inspires confidence, and the shoe keeps its shape when the landing is not perfect. On the downside, you have to accept that it is not a light model nor especially forgiving if what you want is a plush, soft, highly cushioned feel. It is more of a tool than a whim, even if the presentation and finishing suggest otherwise.

Fit, last shape, and feel on foot

One of its most distinctive points is the fit. The forefoot offers enough room for the toes not to feel cramped, and that explains why many users with wide feet find it a reasonable option within On’s lineup. The toe box has a more generous shape than usual for the brand, and the overall sensation is one of controlled spaciousness, not sloppy looseness.

The important nuance is sizing. Different tests and user opinions agree that it can fit a bit short, so it is worth considering half a size up if you are between two sizes. The measured internal length in the lab is slightly shorter than usual, and that difference, while not dramatic, is noticeable when the foot needs a little extra room in front of the toes, especially on long runs or on hotter days, when the foot tends to swell.

The midfoot area can be adjusted well thanks to the lacing system, but it is not universally comfortable. It has a technical, almost visibly engineered feel that will appeal to those who enjoy fine-tuning the lockdown, although it may feel odd to those who prefer a classic, quick lacing setup. It is not a serious flaw, but it is a small friction point in a shoe that aims to feel comfortable from the very first moment.

Cushioning, feel, and running behavior

The midsole combines two ideas that rarely coexist without compromises: enough protection and a firmness that does not collapse under load. In the heel, the height and structure allow it to absorb impact correctly for daily use; in the forefoot, the secondary foam softens the toe-off a little. The result is not soft, but it is balanced, with a level of control that can be very welcome for runners who are not comfortable on overly soft platforms.

In steady movement, the shoe performs better than it might appear on paper. The curved geometry helps the step roll through without snagging, and the whole package does not become excessively stiff, despite the presence of an internal plate and the overall chassis structure. That mix of firmness, some dynamism, and a broad support base makes the experience feel more fluid than its restrained styling might suggest.

This is not a shoe for chasing fast paces with joy, and it does not try to be. Its natural territory is easy runs, active recovery sessions, and long outings where the priority is arriving at the end with the foot stable. For runners who strike on the heel or want very controlled support, the sensation can be quite convincing; for those looking for bounce and couch-like cushioning, on the other hand, the experience falls short.

Weight, breathability, and comfort over long use

Weight plays a major role in its personality. At around 308 grams in a standard men’s size, it does not fall into the lightweight category. That is noticeable when picking it up and also while running, especially if you are coming from more nimble models. It does not hold you back dramatically, but it does constantly remind you that this is not a speed-oriented design.

Breathability, while not outstanding, gets the job done. The upper lets air through properly in the forefoot, although the dual-layer construction and reinforced midfoot take away some freshness. In mild or cold conditions it is not an issue; in heat and humidity, that more enclosed structure can feel denser than a purely summer mesh. Even so, the level of breathability is above the bare minimum and avoids the oven-like feeling that some more closed models leave behind.

Comfort comes more from the shape than from softness. The tongue is thick, the collar padding is generous, and the step-in feel is carefully done, although the heel and ankle may not be perfect for everyone. Some runners will appreciate the hold; others, especially if they have sensitive malleoli, may notice some rubbing in the upper collar area. It is one of those shoes worth evaluating carefully, because the overall comfort is high, but it is not free of details that may split opinions.

Stability and the type of runner it suits best

Stability is its main sporting argument. The platform is wide, the forefoot base is above average in width, and the heel stays reasonably firm without becoming excessively hard. That combination creates a solid stride, with little tendency toward lateral wobble. For runners with mild or moderate overpronation, or for those who simply prefer a constant sense of support, the result can be very satisfying.

The internal plate adds an extra degree of torsional consistency without turning it into an immovable shoe. In fact, longitudinal flexibility is friendlier than expected, which helps keep it from feeling like a plastic boot. That duality between controlled stiffness and sufficient flex is one of the reasons it works better than some isolated data might suggest: it is not a forgiving platform, but it is not a wooden plank either.

In terms of use profile, it fits runners who value routine. Anyone looking for a shoe to log miles at easy paces, walk to and from work, or use in low-intensity gym sessions will find a reasonable ally here. It may also appeal to people who need room in the toe box without giving up serious hold in the rearfoot. By contrast, runners who are very sensitive to weight or firmness will probably be more drawn to softer and lighter alternatives.

Durability, outsole, and behavior over the miles

The overall construction is above average, and that shows in the outsole and the solidity of the chassis. The external rubber is hard and durable, with a clear message: it is designed to withstand frequent use and asphalt wear. In abrasion tests, the outsole performs quite well, reinforcing the idea that this shoe is meant to last rather than impress on a single outing.

The weak spots appear on the upper. The mesh and heel reinforcements do not convey the same robustness as the outsole, which means durability is not uniform. The base may hold up well, but some softer upper areas do not seem designed to withstand the intense abuse of very demanding use. It is not an alarm, but it is an important caveat for anyone logging lots of miles each week or scuffing the shoe with less-than-clean landings.

In cold weather, the foam keeps its composure better than expected. That is noteworthy because the material family used does not usually stand out for being particularly cooperative in low temperatures. Here the feel does firm up, yes, but it never turns into an unbearable board. For those who run in winter or very early in the morning, that stable behavior helps keep the sensation fairly predictable throughout the year.

Price, comparison, and real value in the market

Price is one of the biggest entry filters. This is not a cheap shoe, and On’s positioning places it clearly in the premium segment. That forces you to compare not only performance but also expectations. If you are looking for extreme lightness, abundant cushioning, or an aggressive price-to-performance ratio, there are more convincing options. If you value construction, a roomy fit, and support, the equation changes.

Against daily trainers with support, its behavior is clearly defined: it offers more of a structured feel than many neutral models, but it does not reach the level of foam volume found in other trainers with a maximalist focus. It also weighs more than several contemporary alternatives, and that affects the perception of agility. In return, it conveys a very well-finished product presence, something that remains part of its appeal in a market where not all brands pay equal attention to detail.

Its value therefore depends on the type of runner and what they expect from it. For a user who prioritizes stability, reasonable durability, and a relatively roomy fit, the outlay can make sense. For someone measuring the purchase by lightness, softness, or modern, very plush running sensations, the outlay is harder to justify. It is a coherent shoe, but not a universal one.

A final take on its place within On’s lineup

This model represents a stage of the brand very well: clean design, visible technical focus, and an interpretation of stability that does not rely on exaggerated gimmicks, but on a well-thought-out base and moderate firmness. In a showcase where softer midsoles and ever-higher profiles abound, its proposal goes against the grain with discretion, like a car that does not shout but also does not hesitate when taking the corner.

The overall experience leaves a clear impression. It is a stable, serious shoe with very careful construction, but also heavy, somewhat firm, and expensive. That mix explains why it excites some runners and leaves others cold. It is not an automatic recommendation, but a piece with its own identity, designed for a very specific niche within daily training.

In today’s running landscape, that is something to respect. Not all shoes need to look alike or compete in the same league of sensations. Some, like this one, bet on composure, visible support, and durability that aims to justify every mile. Anyone who understands that language will find a very serious ally; anyone who does not will probably keep looking for a softer and lighter ride.