CloudTec: what the holes under an On actually do
The pods are not decoration and they are not foam. They are cavities, and they cushion by collapsing rather than by being soft – which is why an On feels the way it does, and why a stone on a towpath is a real problem.
Cushioning by shape, not by softness
Most midsoles cushion because they are made of something soft. CloudTec cushions because it is made of something hollow. The pods under an On are shaped cavities that collapse under the landing and firm up as you roll forward, so the give arrives at the start of the step and has gone before the push. It is the most divisive ride in running, and most people know which side they are on inside a mile.
How it works
On calls CloudTec a structural cushioning system, and that word is the whole of it. The give does not come from the chemistry of the foam. It comes from the geometry it has been moulded into: a hollow pod has somewhere to go when it is loaded, where a solid block has only compression.
In the company’s own description the pods compress horizontally as well as vertically, and that is the part that makes the ride feel unlike a soft shoe rather than just like one. A conventional midsole squashes downwards. A cavity that can also deform sideways spreads the landing across a moment instead of a point.
Then it stops. Once the cavity has closed there is nothing left to give, and what is under the foot is material against material. That is why the same shoe can feel soft and then firm inside a single step, and why the push-off feels so direct on a shoe that cushioned a fraction of a second earlier. The two-stage feel is the signature, and it is also the thing people either love or cannot get on with.
What On does not publish
It is worth saying plainly: On publishes no figures for any of this. Their own technology pages describe the mechanism and the sensation. There is no energy-return percentage, no measured stack per pod, no laboratory comparison against a foam midsole.
That is not a criticism of the shoes, and it is not unusual. But it changes what you can do with the claim. Where a maker publishes a measurement you can argue with it, repeat it, or find out that it was measured on a slab rather than on a runner. Where nothing is published, the only available test is your own feet on a treadmill in a shop.
It is also why this page carries fewer numbers than the one about carbon plates, where there is a four per cent figure and a rulebook to argue with. The absence is the honest finding here, not an omission.
The gravel problem
The pods on the original pattern are open to the ground, and a stone is exactly the shape that fits. On tarmac this never comes up. On gravel, on a canal towpath, on a farm track – on anything loose – pebbles wedge into the cavities and stay there, and the shoe clatters until you lever them out with a key.
The brand is well aware of it. The newer road patterns and the trail models close the pods off or fill them, which solves the problem and takes a little of the original feel with it. If you are buying an On for mixed ground, which pod pattern the model uses matters more than which foam is inside it, and that is not something the name on the box tells you.
Who it suits
The ride rewards a rolling stride on a hard, even surface. It suits runners who land lightly and move through the step quickly, and anyone who wants cushioning that does not feel like sinking into the shoe.
It suits less well if you land heavily on the heel and want the softness to last all the way through the step, because that is precisely the moment the pod has run out of travel. And it is not a trail system unless the pods are closed – which, confusingly, some trail models do and some do not.
Where you’ll find it
Shoes on this site built on the pods. They are examples of what the system does in practice, not a catalogue.
Similar and competing technologies
Cushioning a landing can be done with material, with trapped gas, with a cavity, or by not needing to cushion it at all. Most shoes use more than one.
| Approach | How it works | What it trades |
|---|---|---|
| Hollow pods · CloudTec | A moulded cavity collapses on landing, then closes and goes firm. | A distinctive two-stage ride – and, on the open pattern, somewhere for stones to live. |
| Foam alone · almost everything else | The material itself compresses and recovers along the whole sole. | Simple and predictable; heavier for the same softness, and it packs down. |
| Sealed gas unit · Air and similar | A pressurised pocket does the cushioning at one point in the sole. | Very durable; it cushions where it sits rather than along the length of the shoe. |
| Rocker geometry · Meta-Rocker and similar | A curved sole moves the foot through the step instead of cushioning it. | Costs nothing in weight or load; adds no softness at the landing. |
The pods are the midsole rather than something added to it, and how a Swiss triathlete arrived at them is told in the story of the brand.