On Cloudboom Vault Review: A Firm, Fast Trainer-Racer Compared With On's Top Racing Shoes

Introduction

The On Cloudboom Vault is a new addition to the On running lineup in 2026, positioned as a more affordable carbon plate racing shoe aimed at shorter distances. It sits below the Cloudboom Strike 2 in the brand’s range, and it arrives with a rare combination: On’s top Helium HF foam, a carbon-infused speedboard, and a price that undercuts most carbon racers.

This post looks at what the Vault does well, where it falls short of the top racing shoes, and which On alternatives make more sense depending on what you want from a fast shoe.

On Cloudboom Vault: Overview

The Vault costs £190 in the UK and $200 in the US, which is already low for a carbon race shoe, particularly from On. It weighs 222 g (7.8 oz) in UK 9, which is US 9.5, and has a 5 mm heel-to-toe drop. That makes it slightly heavier than the newer Cloudboom Strike 2, which is worth knowing before you buy.

Construction is straightforward for a racer: a fairly lightweight mesh upper with light padding and a significant internal heel counter, two layers of On’s Helium HF foam in the midsole, a carbon-infused speedboard running through that foam, a slight rocker profile, and a generous outsole with good coverage around the forefoot and heel.

Visually it is one of the best-looking shoes in the category, especially in the light blue colorway, and it is one of the few On shoes that has already appeared in sales, dropping to around £130 in the UK.

Ride and Performance

The Vault has a firmer ride than most plated shoes, including the Cloudboom Strike 2. The Helium HF foam feels noticeably firmer here than in the Strike or the Cloudmonster 3 Hyper LS. If you dislike the super-soft direction most modern shoes have taken, that could be a genuine plus. It stayed comfortable even at easy paces during testing.

The ride is snappy rather than bouncy. There is limited compression underfoot, the midsole gives immediate feedback, and the rocker kicks you out quickly. Put more force into the midsole and it sinks in slightly and returns a fair bit of energy, though it is not the ultimate energy return shoe. The narrow platform keeps it nimble and precise, with plenty of ground feel, which suits a quick turnover.

Across more than 60 km of testing, including short reps, steady 10k runs and a very long stop-start half marathon, the shoe handled a wide mix of workouts. The faster the pace, the better it felt. Where it falls short is as a pure race-day shoe: it lacks the bouncy, propulsive feel of top racers, and the firmer midsole may send too much road vibration through for some runners on very long efforts.

Fit and Sizing

The fit is narrow and close across the toe knuckles, with limited length, and it needs some run-in time before it feels natural on the foot. On the move, that tightness delivers a secure, locked-in hold, and the flat padded tongue and heel counter do their job well.

One tester found the toe box too tight at regular sizing and would go half a size up for marathon-length time on feet, while another had enough toe room for long runs at speed with no concerns. The safest read: expect a classic racer fit, try your usual size first, and consider going up if you plan to race long in them.

Alternatives Within the On Lineup

If the Vault’s firmer, more measured ride is not quite what you are after, On’s own lineup offers two clear alternatives that cover the same ground from different directions.

On Cloudboom Strike 2

The Cloudboom Strike 2 is the more effective fast running and racing shoe. It uses the same top-tier Helium HF foam but delivers a bouncier, springier ride with more energy, and it is lighter than the Vault. If you want the full carbon super shoe experience for race day, this is the shoe in the range that does it best, and the LS version’s lightweight upper promises to push it further still.

On Cloudmonster 3 Hyper LS

The Cloudmonster 3 Hyper LS is one of the best super trainers on the market and arguably does the Vault’s fast-training job better, thanks to a softer version of the same foam that gives a bouncier, more fun ride. The catch is the price, at around £270, which puts it in a very different budget bracket.

Buying Advice

The Cloudboom Vault is best understood as a trainer-racer rather than a short-distance super shoe. It handles speed workouts, intervals and mixed-pace training runs well, and it can be raced, but there are shoes you would choose first on race day. Its low price for an On carbon shoe, and its early appearance in sales at around £130, make it tempting as a fast, fun training tool.

The honest caveat is that plenty of fast daily trainers now cost less, around £130 to £150, and offer more low-pace versatility. Many runners will find the Vault too firm for slower runs, and it will likely fall between the cracks of the racing and daily trainer categories. If you specifically want an old-school, firmer, snappier carbon ride for faster training, it earns its place.

Conclusion

The Cloudboom Vault is a shoe to like rather than love. It is beautiful, well built, nimble and genuinely enjoyable at pace, but its firm ride and narrow fit mean it works best as a fast training partner rather than a first-choice racer. Choose it if you want a plated shoe for speed sessions at a lower price; choose the Cloudboom Strike 2 for race day, or the Cloudmonster 3 Hyper LS for a bouncier premium super trainer.