On Cloudflow 5 review

The On Cloudflow 5 works best for:

• Runners loyal to On who want a shoe for fast workouts and occasional daily runs.
• Runners who prefer very firm midsoles and a low-to-the-ground feel, and who actively avoid soft, max-stack designs.
• Athletes training in cold climates who need a warm, durable upper with strong build quality.

The low energy return of the Cloudflow 5 is a real drawback for a shoe built around speed. We found in the lab that the ride feels flat and underpowered, and in our view there are clearly better tempo options like the Adidas Adizero EVO SL or the Saucony Endorphin Speed 5.

From our perspective, it also struggles to justify its price. We believe runners who dislike firm, brick-like foams or a weighty feel underfoot will be disappointed, and faster, cheaper and lighter choices like the Adidas Adizero Adios 9 or the PUMA Velocity Nitro 4 make way more sense.

The On Cloudflow 5 is built more for tempo sessions than for long runs, as its moderate stack height and compact shape limit how much foam sits underfoot. For that reason, we did not expect standout shock absorption numbers.

In our lab test, we measured 123 SA in the heel and 122 SA in the forefoot. Seeing nearly identical results front and back is unusual, but it can happen in dual-foam setups like this one, where the forefoot uses more PEBA and less EVA.

The biggest letdown with the On Cloudflow 5 came right at the start of our lab testing. Measuring just 46.9% energy return is disappointing for a shoe designed for fast running, and when paired with its high price, it becomes a serious concern.

With 32.8 mm under the heel, the Cloudflow 5 clearly stays away from the max-stack category. In fact, it sits below our current average and is better suited for runners who prefer a more controlled, closer-to-the-ground ride.

The forefoot stack came in higher than we expected, as On typically goes for a larger heel-to-toe offset. Here, we measured 28.7 mm of cushioning, which makes the shoe more versatile and friendlier for midfoot and forefoot strikers.

As we hinted earlier, the 4.1 mm drop is much lower than what we usually see from On. It is also lower than the brand’s stated 6 mm when measured at the official World Athletics reference points.

That said, the feel changes a lot depending on how you land. For midfoot and forefoot strikers, the shoe can feel like it has a higher drop, thanks to the pronounced rocker and the curved heel with less foam, which On likely measured slightly farther forward.

Another common trait of On shoes is a firm ride, and the Cloudflow 5 clearly follows that path. In our lab tests, the top PEBA layer (Helion HF) was the softest of the two, yet it still measured a firm 26.8 HA on our Shore A durometer. 

In our view, this shoe makes little sense for runners who prefer soft foams, as even with the CloudTec elements adding some give when the clouds compress, the ride feels far from plush.

The secondary layer uses the familiar EVA-based Helion foam that we have seen in On shoes for years.

At an even firmer 31.4 HA, it reinforces that this model suits runners who enjoy a harsh ride with low foam compression, while gaining clear benefits in stability and predictability.

The Cloudflow 5 features an huge forefoot rocker that encourages quick transitions and works best for fast running, but it can feel awkward at easier paces or for slower runners.

At the back, the aggressive heel bevel helps offset the low drop, keeping heel strikers moving forward instead of feeling stuck.

While the Speedboard is being phased out in some On models, the Cloudflow 5 keeps it to support its fast-paced focus. The plate uses a nylon and fibreglass blend, so it adds guidance without the harsh stiffness you would expect from carbon fibre.

On has released some wide-fitting shoes in the past, but the Cloudflow 5 did not feel spacious during our initial try-on. To better understand the fit, we created our standard gel mould of the interior and took precise measurements.

Our first measurement came in at just 92.7 mm, which is on the narrow side, but it also aligns well with the fast-focused intent of this shoe.

On the other hand, the toebox should work well for runners who want a bit more room for their toes, as we measured 77.2 mm. That places it somewhere in between traditional fits and truly foot-shaped designs from brands like Altra or Topo Athletic.

Our final measurement focuses on toebox height, another important part of fit, and we recorded 24.5 mm.

With such a low value, the shoe further confirms that it is better suited for short efforts rather than long runs.

The outsole performed well in our grip test. It is not outstanding, but a 0.52 score on wet concrete is enough to ensure reliable traction for most days of the year.

The outsole design will feel familiar to anyone who has seen an On shoe before, with the same segmented pods, some covered in rubber and others using reinforced foam, plus a central cutout that exposes the Speedboard plate. Deep grooves run through the heel and midfoot to help maintain flexibility.

Despite a few tweaks aimed at improving flexibility, the Cloudflow 5 still delivers a stiff ride. We confirmed this with a 20.7N result in our 30-degree bend test.

This stiffness mainly comes from the firm midsole combined with the Speedboard plate. While it avoids carbon fibre, the plate still adds noticeable resistance.

If the low-bounce foam was the biggest letdown, weight comes next on our list. A modern shoe built for tempo sessions and fast running should not tip the scale at 9.6 oz or 271g, that feels clearly excessive today.

For context, the ASICS Magic Speed 5 sits in a similar price range and also uses a moderate stack height, yet on our scale it came in at just 7.1 oz or 201g, which highlights the gap.

The upper of the On Cloudflow 5 looks and feels premium to the touch, which is something we expect from the Swiss brand. In that sense, On continues to deliver solid materials and clean execution.

That said, runners looking for strong airflow will be disappointed. In our lab testing, breathability fell short, earning only a 2 out of 5 score.

When we moved the upper over an LED light, it became clear that the toebox lacks ventilation holes, which limits airflow. The tongue helps a bit, but it cannot fully make up for it.

We then examined the material under our microscope, and the reason was obvious. The tightly closed mesh blocks air movement instead of letting it pass through.

Comfort remains good, as expected from On, but this upper shows clear limits in warm weather. For summer running, we believe that ventilation may become a real issue.

Thanks to the very firm Helion foam and the Speedboard plate, the Cloudflow 5 delivers a planted, stable ride despite its compact build. That combination is one of its standout traits, as few shoes in this size range offer a similarly controlled feel underfoot.

Despite the large flex grooves carved into the midsole, the Cloudflow 5 still scores high in torsional rigidity with a 4/5 rating. Once again, the Speedboard plate and the firm foam play the main roles in this result.

On went with a balanced setup here, using a moderately firm heel counter rated at 3/5. It preserves comfort while adding a noticeable layer of support.

The main reason the Cloudflow 5 feels fun at faster paces is its agile midsole layout. With just 107.7 mm in the forefoot, it stays very nimble and reliable when cornering at speed.

The heel is also much narrower than average, measuring just 82.2 mm with our digital calliper. Given this width and the low-drop geometry, it may not be the most sensible choice for rearfoot strikers.

If the limited ventilation was a letdown, the upper makes up for it with stronger durability. The absence of ventilation holes works in its favour here, earning the Cloudflow 5 a solid 4 out of 5 in our first durability test.

The heel padding pushes durability to a perfect 5/5, our highest rating. That is an excellent result and not an easy one to achieve.

Unfortunately, the rubber did not match the strong showing of the upper and lost 1.3 mm under our Dremel test. It is not a deal-breaker, but it is clearly less encouraging than the ones we saw earlier.

Still, 2.7 mm provides sufficient protection, especially for a shoe not meant to be a daily workhorse but rather a more specific training partner.

The insole sits right around the average in thickness, measuring 4.4 mm. These are very standard numbers and align closely with what we usually see in the lab.

If you dislike the feel of the insole or want a bit more vertical room in the toebox, you can remove it. Just note that any replacement probably should be thinner, otherwise the internal space will feel too tight.

After 20 minutes in our freezer, the Cloudflow 5 midsole became 22% firmer. That is not a bad result, although for an already firm shoe we expected a smaller change.

The upper includes some reflective details, but the shoe misses the usual large and super-cool reflective On logo. That feels like a missed opportunity.

As we tested the Cloudflow 5, the laces impressed us with their excellent quality, and the system delivered a secure, pressure-free lockdown. The hybrid setup adds several extra eyelets for fine tuning the fit.

The tongue also feels generously padded at 6.4 mm, which brings welcome comfort over the instep during fast running, an area where many lightweight shoes now feel too minimal.

The tongue is fixed to the sides, which further improves the fit and helps prevent any unwanted movement while running.

From our perspective, it is hard to justify the price of the On Cloudflow 5 unless its design truly wins you over to the point of accepting the higher weight and low energy return. Otherwise, it simply feels too expensive, even with its excellent build quality.

The heel sticks to the usual clean and simple design seen across most On road running shoes.