On Cloudmonster 3 Hyper LS First Run Review: A Featherweight High-Stack Super Trainer

Introduction

On has launched two versions of its new plate-free high-stack super trainer this year: the standard Cloudmonster 3 Hyper, and the LS version tested here. The LS gets the Light Speed upper first seen on the Cloudboom Strike LS racing shoe, along with a higher stack height and a lighter overall build. It is also a lot more expensive, which makes this a shoe you buy for performance rather than value.

After a heavy first day of testing that included a fast track session and an afternoon easy run, the early picture is very promising.

Key Specs at a Glance

The Cloudmonster 3 Hyper LS weighs 216 g (7.6 oz) in a UK 9 (US 9.5), which is about as light as carbon plate racing shoes get, and lighter than any super trainer we have tested so far. That is especially impressive given the very tall stack height, sitting around 45 mm at the heel with a 6 mm drop.

The standard Cloudmonster 3 Hyper costs £210 / $220, while the LS version comes in at £270 / $280, making it the most expensive non-carbon plate shoe tested to date. A pair of socks comes in the box to soften the blow a little.

The Light Speed Upper

The headline feature is the Light Speed upper, a one-piece TPU material sprayed on by a robotic process. It is extremely thin and lightweight, with very little structure at the heel, yet it still holds the foot securely and comfortably at speed.

It also makes the shoe easier to get on than the original LS model. On even includes instructions in the box: step on the heel, slide your foot right in, then pull the heel up and around your foot. It works well.

On fit, our tester went with a normal UK 9 / US 9.5 On size. The fit feels slightly tighter than typical On shoes, with little room around the toes, but no rubbing or hot spots appeared over more than 20 miles on day one. If you are between sizes, sticking with your usual On size seems the safer bet, though trying the shoe on first is always wise with an upper this snug.

The Midsole Formula

The dual-density midsole pairs a full-length top layer of On’s PEBA-based Helion HF, its best foam, with a bottom layer of CloudTec. The firmer CloudTec base almost cradles the bouncy PEBA core, adding stability rather than extra bounce, and keeping the very thick top layer feeling springy and supportive.

The geometry has also been reshaped compared to the original Cloudmonster Hyper, particularly at the heel, where a redesigned section smooths out landings. There is a slightly more pronounced rocker too, and heel strikers running at faster paces will notice a much cleaner roll off the back of the shoe than before.

How It Rides: Two Runs, One Day

The first run was a demanding track session: five sets of 2K reps just shy of marathon pace with 400 m floats, finishing with 1K reps around half marathon pace. Coming in tired at the end of a marathon block, the shoe handled it well, feeling fast, stable, and like an extension of the foot. It turns over quickly and offers a more responsive feel than softer super trainers like the Superblast, which helps when picking up the pace.

The afternoon easy run, about five miles in thirty minutes, showed the other side of the shoe. At easier paces the bounce of the midsole comes through more, and the ride stays controlled and comfortable. One caveat: on very twisty routes and tight corners, the foot can move slightly against the slick upper, so care is needed if your routes rarely run straight.

Outsole and Durability Impressions

Despite the featherweight build, nearly every pod on the outsole is covered by a reasonably thick layer of rubber, with only limited exposed foam. Given how light the shoe is, that level of coverage is a pleasant surprise and should help it wear better than many racing-adjacent trainers.

Early Verdict and Buying Advice

The Cloudmonster 3 Hyper LS is shaping up as a genuinely versatile super trainer: light enough for speed work, stable enough for easy miles, and comfortable over big daily volume. The midsole formula works, the smooth heel transition is a clear improvement over the original, and it is a very enjoyable shoe overall.

The sticking point is price. At £270 / $280 it is not good value by any measure, and alternatives like the Megablast cost considerably less. This is a shoe to buy because you love the Light Speed upper and On’s ride, not because it makes financial sense. For everyone else, the standard Cloudmonster 3 Hyper delivers much of the same formula at a lower price.

Conclusion

On has built one of the lightest and most capable high-stack super trainers available, and possibly the most enjoyable shoe in its range so far. If the price does not put you off, the Cloudmonster 3 Hyper LS is a serious contender for everything from easy runs to marathon-pace work.