Thursday, October 05, 2023

ON Cloudflow 4 Review: Simply Enjoyable!

Article by Jeremy Marie

ON Cloudflow 4 ($160 / €169.95)


The CloudFlow 4 is On’s lightweight road trainer. This category is not an easy one for a brand as try to walk a fine line between being snappy enough to handle tempo runs yet still having enough cushioning for longer runs and easy outings. 

And that’s exactly how On has marketed the CloudFlow since its inception: a lightweight do-it-all shoe leaning to faster runs, bringing top technology at a fair price point.

The Cloudflow is one of On’s trademark models, which lands here in its fourth iteration.

All the usual Swiss brand tech is here: the Helion “superfoam” (which is actually not a “super (critical) foam” as per today’s standard), the identifying Cloudtec, and a spoon-shaped Speedboard- a flexible TPU plate that has equally made or broke some On shoes in the past.

This fourth version, the lightest of the lineage, promises a tad more cushioning, and a mellower ride, while still retaining its propulsive character thanks to the rocker profile and the Speedboard plate.


  • The look!

  • Nice fit: a velvet glove with a perfect hold

  • Laces stay tied despite being thin

  • Excellent breathability

  • Ride is snappy without being harsh

  • Pared down Cloudtec limits issues with pebbles getting stuck in underside

  • A real do-it-all snappy everyday trainer.


  • MIght quickly become dirty

  • Outsole wear

  • Price increase


Weight: men's 8.28oz  / 235g (US8.5)    

Sample: men’s  9.17 oz  / 260 g (US10.5)

Stack Height: men’s 31mm heel / 23mm forefoot ( 8 mm drop spec) 

160$ / €169.95. Available October 5, 2023

First Impressions, Fit and Upper

Jeremy: I’ll sound like a broken record but first impressions with On’s shoes are always the same. Or maybe I’m just a fan of their designs. Their shoes simply stand out, with a classy, sporty flavor that definitely rings a bell in me. 

The bright upper with very light shades of yellow is emphasized by the orange inner fabric makes the Cloudflow 4 a real looker.

Talking about the upper, it’s one of the big novelties in the Cloudflow 4, using the same technique as found in the Cloudboom Echo 3 with a thin woven mesh, albeit in a slightly thicker mesh here.

The tongue is gusseted with a fine liner (using 100% recycled polyester) that runs all way to  the very front of the shoe, making for a double-layer upper that’s very soft and airy. Breathability is not compromised at all with this construction, and it does an excellent job at keeping the thin perforated tongue perfectly in place. 

There’s a minimal amount of cushioning on the tongue to get rid of pressure from the laces, and I must admit that this works perfectly well. 

The thin laces may worry some people but everything is perfectly executed here.  They stay tied, do not put excessive pressure despite their thIn profile and have a slight amount of stretch. Laces eyelets keep the same simply effective approach that seems to define the Cloudflow 4, replacing the hole with a loop at the base in order to get some more adaptability to wider foot shapes and accommodate foot swelling. 

The toe box is of very standard size, not too wide or narrow, and finalizes a very nice fit from the instep to the front of the foot.

I have a slightly wide foot with high-ish instep and find the fit of the shoe to be perfect for my foot shape. 

The ankle and heel collars are using a homogeneous amount of cushioning under the orange liner. The semi-rigid heel counter is of standard size, so rear foot hold relies solely on this cushioning to ensure a perfectly good heel hold. I’ve never experienced slippage nor discomfort on this area, be it with lightweight or midweight socks.

As a comparison with the fit of another On, the Cloudgo, we can consider the CloudFlow to be a stripped down version of On’s everyday trainer: a lighter upper, less cushioning, a more racy fit, but without losing anything in comfort.


Jeremy:The midsole uses On’s Helion foam that tends to appear in different flavors depending on the shoe. 

The Cloudflow 4 has dual density CloudTec (i.e the trademark Clouds that you see in the midsole, or the pillows, the holes…call them as you like, but they’re officially part of CloudTec, with the midsole layer itself ) that uses both the foam and the compression capabilities of those clouds to ensure the cushioning. The dual density lies in the different durometers of the foams used for the base midsole on one hand (the yellow layer on top) and the clouds themselves on the other hand (and all the white midsole layer). 

The upper layer is firmer than the base one, which contributes to the snappy feeling of the shoe. My understanding is that the Speedboard plate is located between those layers, and it doesn make things too harsh as I’ve experienced in the first CloudUltra, or even the Cloudrunner that did not work at all for me.

In the Cloudflow 4, the foam is softer than before, without turning the shoe into a soft one per se.

Despite the stack numbers being close to the previous version, with a drop that increased to 8mm from 6mm, the midsole looks more substantial, and is less firm, at least from the memories I have from the first CloudFlow. This is a clear trend in On’s lineup, that is usually described as firm despite the marketed Clouds mellowness: their shoes are less firm (some people might use “harsh”), and that’s clearly for the best.

One of the greatest differences with the previous iteration is the now filled center channel of the midsole.

In the Cloudflow 3, the Speedboard was clearly visible in this channel, and that was a lot of midsole material lacking. Now, the midsole fully covers the Speedboard, hence bringing more material to compress during the run, increasing the amount of cushioning. 

The Speedboard still plays a big role in the shoe’s snappy character, it’s sensible during toe-off, but its sometimes bad aspects (making the ride too harsh) is now tamed.

The 8mm drop…i cannot feel it. I’m not very sensitive to drop differences, especially nowadays where midsole geometry eases transition  during footstrike.

The Cloudflow 4 has a clear rocker profile but stays flexible. This works really well with my gait as a mid to forefoot striker. The CloudTec may have some detractors, but it’s a nice way of ensuring flexibility of a midsole, even with a good amount of midsole material.


Jeremy: Filling the center channel of the midsole also brings a nice advantage to the outsole: gone are the days of pebbles getting stuck there.

Other than this quite friendly improvement, the outsole stays true to On’s fashion, with rubber patches at the base of the clouds. There’s not a lot of it, as the ground contact surface is inherently minimized being only effectively on the Clouds themselves, but I didn't have an issue during my runs. 

The rubber grips well on the road, even wet, and insures good traction. 

I even tried them on light forest trails with no harm.

I might just question the rubber durability as the very light lugs on the rubber have seen some wear. But I tend to quickly eat through outsoles so…

Ride, Conclusions and Recommendations

Jeremy: Simply enjoyable. I keep going back to this impression of the Cloudflow 4. The way the shoe fits, the feeling when putting them on, and the way they run is almost refreshing. 

The trend might be towards softer, bouncy midsoles, with high (or excessive?) stack heights, but going back to a snappy, reactive and propulsive shoe with a “relatively” low 31mm heel / 23mm forefoot stack height  as in the Cloudflow 4 has been a real delight.

I tried them first on a hard session (8x2’ at VO2Max pace with 1’ recovery at LT1), and they delivered way above my expectations. They’re no supershoes, but they give back a lot of the energy you can put in your stride.

The combination of the foam which achieves a nice blend of firmness (the material) and softness (the compressive Cloudtec) and the Speedboard work seamlessly.

On pure Z2 runs, the inherent stability of the Cloudflow platform, thanks to the Speedboard, helped me maintain good form as miles pile and always with a slight touch of welcome snapiness.

I have a hard time finding faults with Cloudflow 4. Weight is lower than before and stays quite controlled at 260g for my US10.5. The fit is both comfy and secure, be it on roads or forest trails with some slopes, and most importantly it really runs “natural” and easy. I find it to work as well at my endurances paces as at my ~5k paces, while the shoe never becomes harsh under the foot even when fatigue settles in.

Actually its main issue might be the competition of some very nice shoes in this lightweight trainer category, usually with more aggressive prices. But not a lot of them (or any?) have the same quality craftsmanship, looks and tuned in fit.

Jeremy’s Score: 9.05 10



Index to all RTR reviews: HERE 

On Cloudgo (RTR Review)

Jeremy: The Cloudflow 4 is the perfect speed companion to the CloudGo. Despite the official stack height of the Cloudgo being lower, it feels more cushioned. The Cloudflow complements it on the higher end of paces, where the Cloudgo becomes duller. Keep the Cloudgo for easy days, recovery runs or even slight tempo ones, and the Cloudflow 4 for fast days and even race day.

Adidas Adios 6/8 (RTR Review Adios 8)

Jeremy: The Adios 6 I reviewed is a bit old now, but in essence the current Adios 8 is more or less the same shoe, way lighter and falls in the same category of lightweight trainer as the Cloudflow.

I really enjoyed the Adios 6 at the time, and the comparison with the Cloudflow 4 is not easy.

The Adios 6/8 is more aggressive, even more snappy, more “racier”, but it loses on the versatility front versus On’s new shoe. The Cloudflow 4 is “easier”, more cushioned, comfortable, and will work with a wider audience. The price is a big factor here, with the Adios being cheaper and usually with big discounts available.

Puma Deviate Nitro 2 (RTR Review)

Jeremy: The Deviate Nitro was a real keeper for me - and it’s actually still part of my rotation as the shoe I left at my workplace. It’s just so versatile that I know I can use it whatever the run session schedule. The Cloudflow is more refined, lighter, with a better fit relying less on padding to ensure an efficient foothold.

The Deviate might be tad snappier, as its plate and Nitro Elite foam combination works wonders, and its outsole is amongst the best in the business. The Cloudflow 4 is firmer, with a comparable amount of cushioning, but the Deviate Nitro 2 is my preference. All in all the choice might rely on the fit of the shoes, where the On takes the nod.

Tester Profile

Jeremy MARIE, French, 42y/o. Running since 2013 and quickly transitioned to trails, focused on ultras since 2015 : TDS, Maxi-Race, “100 miles du Sud”, 90 kms du Mt Blanc, GRP 120kms, Some shorter more mellow races (Saintelyon 45 kms, Ecotrail Paris 45 kms…) with always in the mix road and flat running, but not many road races. Recovery/easy runs ~4’45/km - 4’30/km. He has an un-official marathon PR of 2h54 (solo) and 10K PR of 36’25. He does few timed road races.

Cloudflow 4 available now including at our partners
Men's & Women's SHOP HERE

Men's & Women's SHOP HERE

Men's & Women's SHOP HERE
Use RTR code RTRTOP4 for 5% off all products, even sale products

Samples were provided at no charge for review purposes. RoadTrail Run has affiliate partnerships and may earn commission on products purchased via shopping links in this article. These partnerships do not influence our editorial content. The opinions herein are entirely the authors'.

Comments and Questions Welcome Below!
Please let us know mileage, paces, race distances, and current preferred shoes

Men's & Women's SHOP HERE
FREE 2 Day Shipping EASY No Sweat Returns

EUROPE Men's & Women's SHOP HERE

Europe only: use RTR code RTR5ALL for 5% off all products, even sale products 


Men's and Women's SHOP HERE
  • 10% Savings Every Day*  5% Back in Rewards Cash
  • Test Run Shoes 90 Days Worry Free
  • Crazy Fast, FREE Shipping

Men's & Women's SHOP HERE

Men's & Women's  SHOP HERE

Men's & Women's  SHOP HERE

Men's & Women's SHOP HERE
Use RTR code RTRTOP4 for 5% off all products, even sale products

Men's & Women's  SHOP HERE

Men's & Women's  SHOP HERE

Men's & Women's SHOP HERE
FREE Shipping on most orders over $40

Men's & Women's SHOP HERE

Men's & Women's SHOP HERE

Men's and Women's SHOP HERE

Shop BROOKS (click logo)


Find all RoadTrailRun reviews at our index page HERE 
Google "roadtrailrun Shoe Name" and you can be quite sure to find just about any run shoe over the last 10 years

Enjoyed this post? Never miss out on future posts by Following RoadTrailRun News Feed

Please Like and Follow RoadTrailRun
Facebook:  Instagram: @roadtrailrun
Twitter: @RoadTrailRun You Tube: @RoadTrailRun

No comments: