On's Redemption Song: Has the Cloudultra Pro Silenced the Sceptics?

For years, whispering in the ranks of serious runners, there's been a certain narrative about On. You’ve heard it. You might have even said it. "Great for the coffee shop run," they'd say, "but not for a real run." With their unique hollow pods, they were often dismissed as a "fashion brand for boomers," their distinctive shoes more at home on the high street than the high fells. The infamous ‘rock collector’ outsole, which seemed to hoover up every piece of gravel on the path, became a running joke. For many, the ride was just too firm, a punishing experience that left legs feeling battered rather than brilliant.

But hold that thought. Something has changed. The whispers are different now. On, the brand many wrote off as a gimmick, has just dropped the Cloudultra Pro, and it’s not just a shoe; it’s a statement. A meticulously engineered, elite-athlete-approved rebuttal to every piece of criticism ever levelled against them. It’s a shoe that has seasoned reviewers, once staunch sceptics, eating their words and admitting, "it seems they've come a long way."

This isn't just another shoe launch. This is the story of a brand's audacious play for the ultra-distance throne. It’s the culmination of years of feedback, a technological reinvention aimed squarely at the world's most demanding races. The question is, does it deliver? We’re diving deep into the tech, the feel, and the hype to see if the On Cloudultra Pro is the real deal and, just maybe, the shoe that will redefine On's place in the performance running world forever. Get ready, because this is not the On you thought you knew.

Under the Bonnet: What Makes the Cloudultra Pro Tick? ⚙️

To understand the revolution, you have to look at the engine. The Cloudultra Pro is a symphony of cutting-edge materials and design, where every component has been obsessed over to deliver a cohesive experience. Let’s pop the bonnet and see what’s driving this new contender.

The Engine Room: A Midsole Masterpiece

The soul of any running shoe is its midsole, and the Cloudultra Pro’s is a work of art. It’s a complex system designed to do two seemingly contradictory things at once: cushion the foot with plush comfort and provide a stable, dynamic platform for efficient running.

• Helion™ HF Hyperfoam: Forget everything you thought you knew about On's ride feel. The Cloudultra Pro features a dual-layer of Helion™ HF, the brand's PEBA-based "super foam". If you’re a running shoe nerd, you know PEBA is the magic stuff – the same family of foam that revolutionised road racing, known for its incredible energy return and light weight. Here, On has used two different densities. The top layer, directly under your foot, is softer, providing that immediate ‘ahhh’ feeling of comfort and soaking up the initial impact. Beneath it lies a firmer layer that provides the structure and stability, preventing that 'running in treacle' feeling that can plague some max-cushion shoes. It's the best of both worlds: soft landing, stable take-off.

• The Plastic Speedboard®: In a world gone mad for carbon plates, On has made a very deliberate and clever choice. Instead of a rigid, aggressive carbon-fibre plate, they’ve used a TPU-based plastic Speedboard®. Why? Because a 100-mile race isn’t a 10k sprint. While carbon plates offer incredible propulsion, they can be harsh, unforgiving, and unstable on winding, technical trails, especially when fatigue sets in and your form gets sloppy. This more flexible plastic plate provides a smoother, less aggressive ride. It gives the shoe the structure and propulsive 'snap' you want from a modern performance shoe, but with enough torsional flex to let your foot move naturally and adapt to roots, rocks, and off-camber terrain. Reviewers consistently note you don't feel the plate jabbing the ball of your foot, a common complaint with more aggressive setups. It’s propulsion without the punishment.

• Stack, Drop, and Rocker: Let's talk numbers. With a heel stack height of 38.5 mm and a forefoot of 32.5 mm, this shoe is firmly in the max-cushion category. It's built to shield your legs from the relentless pounding of an all-day effort. The resulting 6 mm heel-to-toe drop is a sweet spot for most runners, promoting a natural stride without over-stressing the lower legs. This high platform is sculpted into a pronounced rocker shape. Think of it like the curved runners on a rocking chair; it’s designed to encourage a smooth, efficient transition from heel-strike to toe-off, a biomechanical cheat code that becomes invaluable when you're 80 miles in and just trying to keep moving forward.

The Contact Patch: A Redesigned MissionGrip™ Outsole

If there was one Achilles' heel for On's past trail shoes, it was the outsole. The Cloudultra Pro signals a complete overhaul, driven by data, not just aesthetics.

• FEA-Driven Design: On’s engineers used Finite Element Analysis (FEA) – a powerful computer simulation tool used in Formula 1 and aerospace engineering – to digitally model and test over 200 different lug configurations. They simulated the stresses and strains of a 19-hour run to find the most efficient and effective pattern before a single physical prototype was made. This is a serious commitment to performance.

• Strategic Lug Pattern: The result is an outsole with a lug depth of 3.5 mm around the perimeter and shallower 2.5 mm lugs in the central channel. This relatively shallow depth is a clear design choice. This shoe isn't for a boggy fell race in the Brecon Beacons. It's optimised for the hard-packed, gravelly, and mixed terrain that defines most major international ultramarathons.

• The Central Cutout: A huge channel of exposed midsole foam runs right down the middle of the shoe. This isn't just for looks. It serves two critical functions. First, it dramatically reduces weight. Second, and more importantly, it allows the high-stack shoe to flex and articulate through the midfoot. This ability to conform to the ground is a massive contributor to the shoe's surprising stability.

The Cockpit: Fit for a 100-Mile Journey

The upper is where you live for the many hours of an ultra, and it needs to be perfect. On has created a masterpiece of comfort and security.

• Zoned Leno Weave Upper: The material is a high-tech Leno weave made from a blend of TPEE and recycled polyester. It's not a uniform mesh. It’s strategically 'zoned' – reinforced in high-stress areas for durability and lockdown, and more open in others for maximum breathability and drainage. It feels light, airy, and incredibly strong.

• The Ultra-Distance Fit: This is a standout feature. The fit is intentionally roomy, with a broad and wide toe box. Any ultra-runner knows that after 10+ hours on your feet, they swell. A lot. This generous volume prevents your foot from being constricted, saving you from blisters and blackened toenails. But roomy doesn't mean sloppy. A padded tongue and clever ribbed laces that grip the eyelets allow for a fantastic midfoot lockdown, keeping you secure without being restrictive.

• Potential Niggles: No shoe is perfect for every foot. A couple of minor points have been noted by testers. The protective toe bumper, while great, was felt by one reviewer on their big toe. More commonly, some found the ankle collar sits a fraction high on the outside of the ankle. However, its soft padding meant that even testers who noticed this reported no actual rubbing or issues, even over a 108km race.

How Does It Actually Feel? From Pavement to Peak ⛰️

Specs and tech are one thing, but the only thing that truly matters is the ride. How does the Cloudultra Pro feel when the rubber meets the trail? The consensus is that it delivers a unique, sophisticated, and incredibly effective experience.

A Magic Carpet Ride? Cushioning and Comfort

The feeling underfoot is all about balance. It's been described as "dynamic yet comfortable". This isn't a super-soft, marshmallow-like shoe where you lose all sense of the ground. The dual-density Helion™ HF foam provides an initial softness, but the overall ride is more of a "planted firm" feel. It's protective and cushioned, but also responsive and connected.

This is a purpose-built character for ultra-distances. When you're running for that long, sheer softness can lead to instability and wasted energy. The Cloudultra Pro aims for leg preservation. One reviewer commented that after long, punishing climbs, their legs felt noticeably "less fatigued" than in other shoes. Another, after a gruelling 108km race, found the midsole felt just as fresh and responsive as it did at the start, with no signs of packing out. This is a shoe built to feel as good in hour 15 as it does in hour one.

The High-Stack Stability Paradox

Here’s the most surprising thing about the Cloudultra Pro: its exceptional stability. Logically, a shoe with a nearly 40mm stack height should feel like running on stilts, especially on technical, uneven ground. Yet, reviewer after reviewer has praised this shoe as being remarkably "stable and controllable for its stack height", more so than many of its key competitors.

How did On pull off this magic trick? It’s not one single feature, but a masterclass in systems engineering:

1. The Dual-Density Midsole: The firm base layer creates a wide, stable platform that resists twisting and compression.

2. The Flexible Plate: The plastic Speedboard® provides structure but allows the shoe to flex and adapt to the ground, unlike a rigid carbon plate which can feel precarious.

3. The Midsole Geometry: The central channel and pronged shape allow the shoe to articulate and bend, conforming to rocks and roots rather than fighting them.

This trifecta of design elements works in harmony to solve the high-stack stability paradox. It provides the protection of a max-cushion shoe with the confidence of something much lower to the ground. That said, it's not invincible. On the absolute gnarliest terrain – think scrambling over thick, clumpy gravel or scree fields – its height is still noticeable. It's not a fell-running shoe, but for 95% of what you'll encounter in an ultra, the stability is a game-changer.

Efficiency: The "Pro" Advantage

The Cloudultra Pro is built for efficiency. The ride isn’t about explosive, raw speed, but a smooth, rolling, and sustainable energy return designed to save your legs over the long haul. The combination of the rocker geometry, the responsive foam, and the subtle push from the Speedboard® creates a feeling that you can just "lean into" your stride and let the shoe do the work.

Testers repeatedly reported being "always surprised by my paces", running faster than their perceived effort. This is the holy grail for an ultra shoe. It's designed to promote smooth transitions and keep your legs feeling fresh deep into a race, helping you maintain good form when fatigue is screaming at you to stop. It's a tool for metabolic efficiency, where saving every last calorie and muscle fibre is more important than your pace for any single mile.

Grip and Versatility: The Strategic Compromise

The MissionGrip™ outsole has been a point of discussion, but a clear picture has emerged. It performs brilliantly on the terrain it was designed for: dry and rocky singletrack, hard-packed dirt, gravel fire roads, and even pavement. For these conditions, which make up the bulk of most major ultramarathons, the grip is confidence-inspiring.

The acknowledged weakness, a direct result of the 3.5mm lugs, is its performance in the soft stuff. It is decisively "not a soft ground shoe by any means". This isn't a flaw; it's a deliberate compromise. On has optimised this shoe for versatility on the runnable trails of iconic races like UTMB or Western States. If your running life is a constant battle with British mud, you'll need a shoe with deeper, more aggressive lugs. But for its intended purpose as a 'hybrid' ultra racer, the traction is more than up to the task.

Clash of the Titans: Cloudultra Pro vs. The Rivals ⚔️

No shoe exists in a vacuum, especially not one with a £240 price tag. The critical question for any discerning athlete is how the Cloudultra Pro stacks up against the other super shoes vying for the top spot on the podium.

Head-to-Head Analysis: Choosing Your Weapon

The choice between these titans comes down to your priorities, running style, and target race.

• vs. Hoka Tecton X 3: This is the most direct rival. Both are max-cushion ultra-racers. The key difference is the engine. The Hoka's parallel carbon plates give it a more aggressive, poppy, and propulsive feel. The On's plastic plate delivers a smoother, more forgiving, and ultimately more stable ride. For elite athletes pushing the pace, the Tecton X 3 might offer a slight edge in raw speed. But for many runners, especially those in the mid-pack or concerned about stability, the Cloudultra Pro's controlled efficiency will be the smarter choice for a 100-mile journey. It’s the controlled cruise missile versus the aggressive fighter jet.

• vs. Saucony Endorphin Edge: The Endorphin Edge is a different beast altogether. It’s built for one thing: speed. It’s significantly lighter and uses a stiff Carbitex carbon plate for a furiously fast and fun ride. However, that focus on speed can make it feel 'tippy' and less secure on technical terrain. The Endorphin Edge is a pure race-day weapon for faster runners on smoother trails. The Cloudultra Pro, while no slouch, is the more versatile workhorse, prioritising leg preservation and stability, which are arguably more critical for finishing a truly long and gruelling ultra.

The Cloudultra Pro carves out a brilliant niche. It sits perfectly between the non-plated super-cushioned shoes and the aggressively plated racers. It offers a dose of modern propulsion from its Speedboard® without the instability or harshness of a full carbon plate, making it a hugely appealing option for a vast range of ultra-distance athletes.

The Final Word: Is the Cloudultra Pro Your Next Ultra Shoe? 🏆

After deconstructing the tech, synthesising the reviews, and placing it in the competitive landscape, the On Cloudultra Pro emerges as a triumph. It’s a sophisticated, purpose-built machine that absolutely delivers on its promise to be a top-tier contender for the ultra-distance crown.

Who Should Buy It?

• The dedicated ultra-runner: This shoe is built for you. If you're training for and racing events from 50k to 100 miles, its blend of efficiency, protection, and stability is hard to beat.

• The mid-pack hero: While elites will love its performance, the shoe’s forgiving and stable nature makes it an exceptional choice for runners who will be on their feet for 15, 20, or even 30+ hours.

• The efficiency seeker: If you prioritise leg preservation and a smooth, rolling ride that helps you maintain form when you're deep in the pain cave, this shoe is your new best friend.

Who Should Avoid It?

• The mountain goat: If your runs consist primarily of scrambling up extremely technical, rocky peaks, a lower-profile shoe will offer better ground feel.

• The mud-lover: If you live and run in a place where trails are perpetually soft and boggy, the 3.5mm lugs won't provide the bite you need.

• The budget-conscious runner: Let's be blunt. At £240, this is a huge investment. It's a premium product with a premium price tag.

Is It Worth the Money?

For the serious ultra-runner, the consensus is a resounding yes. The performance, comfort, and efficiency it provides over such extreme distances are a tangible return on investment. It's an investment in fresher legs, better race experiences, and potentially, a new PB. When a shoe is this good, the price becomes less of an obstacle and more of a justification.

The bottom line is this: the On Cloudultra Pro is an unqualified success. It is not just a great shoe; it is a brand-defining moment. With one product, On has silenced the doubters, systematically addressed years of valid criticism, and proven it belongs at the very top of the performance running world. This is more than a shoe; it's a new beginning. The king of the ultra-distance trail may have a new contender for its crown.