The On Cloudboom is firm, fast, slim and airy.

A very distinctive shoe with the aim of helping you to PB over half marathon to marathon

A firm, fast shoe for slim footed runners over short-middle distances

  • Weight 225g (M) 185g (W)
  • Heel-To-Toe-Drop: 9mm
  • Type: Road

Price: $299.95A firm, fast shoe for slim footed runners over short-middle distances

  • Helion superfoam gives much needed bounce
  • Carbon-infused plate for speed but a little over-firm
  • Very breathable mesh with large ventilation holes.

In general we’re all in favour of shoe brands sticking their neck out and trying something new. This is a very distinctive shoe with a specific aim (albeit one that seems to be the theme of 2020 in Shoe World): to enable to you PB from half marathon to marathon distance. That’s a bit of a balancing act since such a shoe needs to be quick enough for the half but cushioned enough for the 26.2. Our testers had mixed feelings about whether the Cloudboom hits the bullseye in this regard with the quick summary being: you might be able to do that in this shoe, but only if you’re a fast, light, experienced club runner.

Very firm feel

For this shoe On has changed the composition of its Speedboard: essentially a plastic platform that the outsole cloud pods are attached to. The Speedboard here has carbon infused into it to create a plate that aims to give better energy return. The overwhelming feedback from everyone apart from the fastest runners was that it’s too firm and aggressive to be a long run shoe, although some thrilling outings were reported over shorter distances up to 10 miles.

More Bounce Per Ounce

The carbon Speedboard has been sandwiched in between two layers of Helion superfoam, On’s highest spec midsole foam. It was launched just before the advent of carbon plates and at the time was heralded as one of the springiest materials on the market. The bounce from the shoe was very good indeed, and accentuated by the pronounced toe spring (the upwards ‘Aladdin’s slipper’ curve at the front of the shoe) which enabled you to pop off your toes nicely. Downhill running was a particularly lovely experience.

Could be more responsive

One irritation, though, is the strange clumpiness in the midfoot. A shoe as ‘racy’ as this looks and feels in the hand should roll through effortlessly from heel to toe but our testers found that, while there was adequate shock attenuation in the heel and the aforementioned spring from the forefoot, the shoe felt almost resistant and excessively stiff in the middle part of the heel-toe roll-through. Perhaps this is a consequence of trying to make the Cloudboom robust enough for marathons.

Slim fit

If you’re a fan of On shoes and find that their models pretty much run to the same size for your feet, hold up: the Cloudboom are different. They’re demonstrably a slimmer – and even slightly shorter – fit than the usual On outline, so it’s advisable to try before you buy. As a final small point: the upper also features some of the largest ventilation holes (around the outside of the lacing area) that we’ve seen in a while, which makes for outstanding breathability but does limit the shoes to dry weather only.


An interesting innovation and a more than competent shoe that many runners will love if you ignore its intended purpose. Lighter athletes with slim feet: buy this for 5K to half marathon if you’re looking for a ‘marginal gains’ model.

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