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On Cloudflyer 4: For the On Traditionalist
By Matthew Klein

On Running has been making some big moves recently. From the increasing number of athletes being sponsored, to a true super shoe coming to market, then actually making comfortable cushioned running shoes like the On Cloudmonster and the On Cloudsurfer 7. Despite being the "cloud" company, many of On's models have been quite firm. As walking shoes, they are comfortable, hence the increasing number of people wearing them as casual shoes (especially here in Southern California). For running, they attract a specific type of runner who likes better ground feel and firmer rides. For those concerned about On becoming a soft shoe company, the On Cloudflyer 4 maintains the tradition of a firm ride. Featuring a wider, more comfortable upper and a stable neutral ride, the Cloudflyer 4 stays as a firm shoe while adding a stronger rocker to keep things moving.

On Cloudflyer 4
Price: $169.95 at Running Warehouse
Weight: 10.8 oz, 306 g (men's size 9), 9.4 oz, 266 g  (women's size 8)
Stack Height: 37.7 mm / 31.7 mm 
Drop: 6mm (11mm drop per On)
Classification: Mild Stability Daily Training Shoe


The On Cloudflyer 4 is a mild stability daily training shoe for those that want a little thicker upper and a firm rolling ride. The upper is plush with a thicker knitted liner that makes for a lower volume fit in the forefoot with a secure and slightly snug fit elsewhere. The ride is extremely firm and strongly rockered, which combined the weight makes it better for slower efforts and walking. With a combination of newer and older of stability, the On Cloudflyer is a more traditional On design for those who want to feel grounded and roll along. 

: On Cloudswift


The On Cloudflyer 4 fits me true to size in my normal men's US size 10. The upper is plush with extra padding throughout. The height feels lower because of this, especially in the forefoot and almost made the shoe feel short. This material immediately broke in and began to feel true to size. As the material compresses the fit transitions from normal to slightly wider. This creates a slightly relaxed fit with a little extra room in the heel. The knitted liner mesh is comfortable against bare skin. I have worn this shoe sockless extensively and not had any issues. The midfoot features a half gusseted tongue (front half) that is on the thicker side. The part closest to the ankle is free floating but I had not issues with slippage. The laces are thin and I had to pull them tight to get a secure fit. The midfoot fits fairly normal and transitions into a normal width heel thanks to the extra heel collar padding. The heel counter is external with plenty of internal padding.

My heels had no issues with this shoe, although I do expect the fit and pressure at the rearfoot to change as this material breaks in. The security was fair. I have had some heel slippage due to the wider heel and had to really tie the laces down. I would suggest lace locking this shoe for security especially if you are prone to heel slippage.


The On Cloudflyer 4 is a firm riding, heavier daily training shoe for slower runs and walking. The midsole features two columns of cloudtec elements with a midline groove in the heel and midfoot that transition into a full width forefoot. The full length Helion foam is quite firm and a highly curved sole design makes for a rockered ride. The 10.8 oz weight is extremely noticeable, making this a shoe only for slower efforts. The heel drop feels higher initially and On Running lists this shoe as having an 11mm drop. Once it breaks in, the rocker makes this shoe feel like a moderate drop shoe. The heel transition is fairly smooth thanks to a well rockered heel and a slightly posterior lateral heel. The midfoot transition is solid thanks to the rockered sole and the torsional stiffness of the speedboard. The forefoot has moderate flexibility for a shoe with a stiffening agent and provides a firm and smooth transition off the toes. This is not a shoe for those with limited great toe mobility as there is still a surprising amount of bend up front.

The On Cloudflyer 4 is best for slower runs and walking. Those with a higher cadence that want to roll along in a firmer shoe will enjoy this shoe most. I struggled with it due to the weight while running, but enjoyed the rocker and smoothness during walking. I have over 20 miles of running on my pair and another 15-20 of walking. There is only mild abrasion on the posterior lateral heel and the durability appears to be slightly above average. Use-wise, this shoe can only handle road. I have still gotten rocks stuck in the central groove so would not take this shoe on anything other than smooth hard surfaces.


The On Cloudflyer 4 is a mild stability shoe that uses several newer elements of stability and a partially traditional one. The platform is wider except for a mildly narrowed midfoot. There is also a large guidance line through the heel and midfoot. The medial clouds do compress less than the lateral clouds, creating a mild post/wedge like design. This is mild but noticeable as the shoe breaks in. The speedboard also adds a high level of longitudinal stiffness helping to keep things centered. For those sensitive to sidewalls, these are not present at all although the external heel counter and padding does a mild job of centering the heel. The firmer ride throughout also adds inherent stability, especially at the forefoot. These elements are all mild and are most present in the rearfoot and midfoot. 

Thoughts as a DPT: Variations in Midsole Softness Perception with Varying Speeds and Cadence
By Matthew Klein

On Running shoes are typically firm despite the large clouds shaped cushioning devices. Although still firm, I have found them to be a little softer and better suited for me during walking. There are several reasons for this. During walking, the impact into the ground and ground reaction forces are far less than during running (Nilsson & Thorstensson, 1989). That may mean there is less compression of the midsole. A foam that is compliant may still feel firm if it compresses completely before being loaded completely. Loading a material slower may also prevent it from getting the "bottoming out" feeling where it is completely compressed. With higher impact forces, speeds of forces and ground reaction forces, running will compress a shoe's insole and midsole more and faster. A compliant and resilient foam that bounces make may provide a responsive feel especially when loaded more during running. This may create some of the variations in how a shoe feels underfoot.

We also know that biomechanical factors, like cadence, can modify the forces underfoot. A higher cadence has lower ground reaction forces compared to a lower cadence (Farina & Hahn, 2021). Higher ground reaction forces usually means more impact force per footstrike. Someone like me, who has a longer stride and lower cadence, will have greater impact forces (have you seen my posterior lateral heels?) than someone with a shorter stride and higher cadence. The sharp rocker design of the Cloudflyer 4 also feels better running with a higher cadence. This may be a combination of hitting the geometry at a better angle but also compressing the foam less and not bottoming out the shoe. Some people may really enjoy the ride of this shoe, but their mechanics will need to match its design for that. 


Farina, K. A., & Hahn, M. E. (2021). Increasing step rate affects rearfoot kinematics and ground reaction forces during running. Biology11(1), 8.

Nilsson, J., & Thorstensson, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica136(2), 217-227.


While the fit is decent, my major recommendations are focused around the midsole. The look is fine, but the cushioning and weight need to match how little midsole there is compared to other companies with full length foam midsoles. It is unacceptable for this shoe to weigh 10.8 oz (men's size 9) and have such huge spaces in the midsole. It is also way too firm (I know what I just wrote in the DPT thoughts section). The midsole material needs to have its density drastically reduced to improve compliance of the material as well as to lighten it. On needs to learn from some of the new foams they are working with in their faster shoes because the weight and firmness make this shoe uncomfortable for running for me. For a "cloud" company, these are heavy and firm.

As mentioned, the fit is fine but it is far more plush than I think it needs to be. The extra material makes the shoe feel lower volume and more snug. This may be great for those with more narrow feet but those with wider feet may have trouble until the material breaks in. This is also a source of extra weight. Given how good On Running does with its apparel, I'm sure this upper can be lighter yet still secure.


The On Cloudflyer is best for those wanting a mild stability, highly rockered, sturdy shoe with a comfortable slightly wider fitting upper for easy runs and walking. While it can certainly roll, the shoe is quite heavy. This took some adjustment to my mechanics but those who have a shorter and faster stride may enjoy this more than someone like myself who has a longer stride. The fit is slightly wider and relaxed, requiring some additional lockdown while being a great option for sockless wear. There is truly mild stability here with firmer medial clouds compared to the lateral ones combined with a speedboard and guidance line. It is biased laterally, so those looking for the rare mild stability trainer may enjoy this.

Although many people may come to this website looking for running shoe reviews, the On Cloudflyer really shines as a walking shoe. The rockered ride, mild stability and sturdy feel make it an excellent shoe for long days on your feet. Those with mobility deficits (ie stiffness or lack of motion) at the ankle will do particularly well, although the stiff flexibility at the forefoot may be better for those who have at least moderate movement at their toe joints. While I will not keep this shoe in my running rotation, it has earned a spot for walking and longer standing due to the upper comfort, mild stability and rockered ride that works far better dealing with the impact forces of walking than running.


Fit: A-/B+ (Comfortable, plush upper. Fits slightly relaxed and wider when it breaks in. Great for sockless wear but has heel slippage with socks)
C+/B- (Extremely firm and rockered ride. Better for walking than running unless you want that kind of ride)
Stability: A- [Mild Stability] (wider platform, firmer, firmer medial pods)
DPT/Footwear Science: B- (Stable ride, but unnecessarily heavy and firm for the stack height and lack of midsole)
Personal: B- (Great shoe for walking and standing all day but firmer ride and weight make it feel too heavy for running)


On Cloudflyer 4
Price: $169.95 at Running Warehouse

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Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles area, I am currently taking clients for running evaluations.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at On Running for sending us a pair.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

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Brooks Adrenaline GTS 23

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