On Cloudmonster 3 Hyper LS Review: A Superb Super Trainer Held Back by Fit and Price

Introduction

The On Cloudmonster 3 Hyper LS sits at the very top of On’s super trainer range, and it earns that position in the most literal sense: it is the lightest, most exciting shoe in the On lineup, built to deliver a versatile and genuinely fun ride across a massive range of daily training. It is also extremely expensive, at £270 or $280, with the standard Cloudmonster 3 Hyper (still very expensive itself at £210 or $220) sitting a fair bit below it. You do get a free pair of socks with the LS to soften the financial blow a little.

So the question is simple: is the best ride On has ever produced worth this kind of money, and can you actually get the shoe on your feet? Let’s dig in.

Key Specs and First Impressions

This is a seriously light shoe for its class. In a UK size 9 (US 9.5), it weighs just 216 g or 7.6 oz, with a 6-mm heel-to-toe drop. Official stack numbers have not been published, but it measures around 45 mm at the heel and 39 mm at the forefoot, so this is a proper mega-stack shoe that is unbelievably light for its cushioning level.

That combination of huge cushioning and very low weight is the whole appeal, and it places the shoe squarely in lightweight max-cushion super trainer territory alongside shoes like the Asics Superblast 3 and Megablast.

Design and Construction

One of the main reasons this shoe is so light is the Lightspeed upper: a one-piece material sprayed onto the shoe by a robot. There are no seams and really nothing to it at all, which gives a very flexible, weightless feel on the foot. That same minimal construction, however, can create fit issues if it does not work for you out of the box, which we cover in detail below.

The midsole uses two different materials. The dominant layer is a big, chunky top layer of Helion HF, On’s Pebax foam and the best foam in the On range. It is bouncy, lightweight and a lot of fun, and in this version it now extends the full length of the shoe, whereas the original Cloudmonster Hyper only had it under the forefoot. Underneath sits a layer of On’s signature CloudTec foam, which acts as a frame to stabilize the bouncy foam.

On the outsole, rubber coverage is quite generous, covering nearly all of the pods on the bottom of the shoe. Despite the very low weight, you get a significant outsole, which is good news for daily training durability.

Fit: The Big Story

Fit is definitely the biggest story with this shoe, and it is genuinely divisive. Experiences vary widely. Some testers found the fit very good and very easy: the foot slips in, the shoe holds securely even for fast running, with only a little lateral movement, and the seam-free upper means nothing rubs or irritates the foot. For runners with narrower feet and lower arches, it worked straight out of the box.

For others, it was a different experience entirely. Some runners have struggled even to get the shoe on. The narrow entry point of the sprayed upper grabbed socks and made every wear a wrestle, and the lack of a heel pull or tongue pull made it harder. Once on, some wearers experienced pinching across the top of the foot and even some numbing, particularly runners with wide feet or high insteps. Going a full size up made the toe box too long and the shoe unwieldy, so sizing up is not a clean fix either. There have also been reports of the upper digging into the top of the foot on some runs.

The core issue is that removing traditional laces removes the ability to tailor the fit. If the sprayed upper does not suit your foot shape, there is nothing you can adjust. The practical advice: try these on in store if at all possible, and if you must order online, make sure you can return them. Do not buy blind.

On the Run: Performance

Once the fit question is settled, the ride is where this shoe shines. Across testing that included track sessions, strides, a 10-mile tempo, a threshold session on a double run day and plenty of easy running, the Cloudmonster 3 Hyper LS proved itself one of the most versatile shoes on the market. It performed well in every single run type, and excelled in several.

The ride is smooth and enjoyable, with the top layer of Helion HF being the dominant feeling underfoot. This matters because CloudTec can deaden and dull a ride when it plays too large a role, but here the Pebax foam is what you actually feel: the bounce, the fun, the energy. The CloudTec layer provides a useful stabilizing frame instead.

At easy paces, including proper recovery runs and warm-downs, the shoe feels notably stable, which is not always true of super trainers that can feel wobbly at slow speeds. When the sprayed upper fits well, it makes the shoe feel like an extension of the foot, with a weightless, connected quality that few shoes offer.

Steady and tempo running is the absolute sweet spot. The combination of comfort, stability, low weight, bounce and a fast, smooth turnover makes it ideal for ticking off the miles, and it works beautifully as a long run and tempo run shoe. On longer reps, it handled a demanding session of 5 x 2K at 3:30 per kilometer with quick 400 m floats and a 1K at 3:20 well. It is not the absolute best for short reps, losing a little propulsion compared to plated shoes, but it is genuinely fast, largely because it is so light.

Durability and Grip

The outsole has a lot of rubber, and the grip is very good. After 50 km of testing, there was minimal visible wear, even in the heel area where landing typically causes the most abrasion. For a shoe this light, the durability signal is strong, and the generous rubber coverage supports its role as a daily trainer.

Stability and Easy Miles

Stability is a genuine strength. Even as a very high-stack shoe, the foam setup makes you feel a bit lower to the ground and secure. Some testers noticed slight wobble on the sides of the shoe toward the end of some runs, but generally the platform held up well.

Legs did not feel beaten up after harder or longer efforts, and the shoe never felt overly aggressive. If there is a caveat for some feet, it is that the upper may not lend itself to really long miles for wider feet, with around an hour to an hour and a half being the comfortable limit in some cases.

How It Compares

Against the Asics Megablast, the Cloudmonster 3 Hyper LS is lighter and a bit more stable, but the Megablast has more energetic foam and is perhaps slightly better at flat-out pace, and it is a fair bit cheaper. The Asics Superblast 3 is more of an easygoing, cushioning-focused super trainer, while the On offers a higher gear and feels great across more paces, but again at a much lower price.

The Kiprun Kipstorm Tempo, less than half the price in the UK, matches it for fast workouts with very responsive foam despite being slightly heavier, making it arguably better value for the same job. The standard Cloudmonster 3 Hyper feels surprisingly different: heavier, less energetic, and not great for fast efforts, so within these two On models, the LS is clearly the better shoe, though both are expensive.

Buying Advice and Verdict

Judged on ride alone, the midsole makes this one of On’s best performance shoes to date, and it is arguably the best On running shoe tested so far. It is miles ahead of the regular Cloudmonster 3 Hyper, and it gives On a genuine max-stack super trainer that sits well with the competition.

But two things hold it back. First, the fit may simply not work for you, and if it does not, there is no way to adjust it. Second, the price is very hard to justify: £270 or $280 is top-tier race shoe money for a training shoe, and it makes shoes like the Megablast and Superblast look cheap. If you have deep pockets and the fit works for you, this is a fantastic daily trainer and more. If not, there are many excellent alternatives, or the standard version, which offers a similar (slightly heavier) experience for less money.

Conclusion

The On Cloudmonster 3 Hyper LS is a superb super trainer with one of the most versatile and enjoyable rides available, and its sprayed Lightspeed upper delivers real weight savings and a unique connected feel. Whether you should buy it comes down to two checks: can you get on with the fit, and can you stomach the price? If both answers are yes, you have potentially a really great shoe on your hands. If either answer is no, there are cheaper options that will serve you just as well.