Our verdict

We love the On Cloud X because it's a workout shoe with a stylish sneaker appeal. We barely felt it on our feet thanks to its amazingly lightweight and airy design. Surprisingly, the shoe also made us feel planted and very stable throughout the workout. However, we still don't find all of this enough to justify the shoe's high price point, especially given how frail its upper is. Better wait for a discount.

Pros

  • Very lightweight
  • Highly breathable
  • As soon as we put the On Cloud X 3 AD on, we knew that stability is the shoes forte
  • Stable platform
  • Flexible forefoot
  • Secure lockdown
  • Sustainable materials

Cons

  • Grounded, firm, and wide, it did a great job preventing the ankle from excessive rolling
  • Unreasonable price

Audience verdict

87
Great!
  • Excellent ground feel

Who should buy

Heel stack lab:

  • On On Cloud X 3 AD
  • need a lightweight trainer (the On Cloud X 3 AD is among the lightest in our catalogue)
  • Grounded, firm, and wide, it did a great job preventing the ankle from excessive rolling

On Cloud X review

Who should NOT buy

One major problem with the On Cloud X is its sky-high price. At £150, it is significantly more expensive than training shoes on average (£110).

Heck, it is even more expensive than the flagship Crossfit shoes like the Nike Metcon 8 and the Reebok Nano X4 oz / 247g.

Another big concern is the shoe's durability. Based on our lab tests, the wear resistance of the On Cloud X 3 AD is much lower than its premium price. If you go hard at the gym and include rope climbs into the routine, go with any of the aforementioned Nike or Reebok shoes instead. The NOBULL Outwork is another bulletproof option. 

On Cloud X lab test

Cushioning

Heel stack

The brand refers to the shoe's cushioning as "low," implying that it is not max-cushioned and is low to the ground.

Using a calliper, we measured its heel stack height at 25.5 mm. This is considered low for a running shoe but is just average for a cross-trainer. You do need less cushioning underfoot to feel stable and in control of the movement.

On Cloud X Heel stack
Test results
On Cloud X 3 AD 25.5 mm
Average 24.8 mm
Compared to 41 training shoes
Number of shoes
13.7 mm
Heel stack
36.2 mm

Forefoot stack

In the forefoot, our calliper shows 16.3 mm of stack height. This is about 2 mm lower than the average.

Keeping the toes so low to the ground, the On Cloud X 3 AD felt quite steerable, quickly adjusting to changes in the foot position.

On Cloud X Forefoot stack
Test results
On Cloud X 3 AD 16.3 mm
Average 18.4 mm
Compared to 41 training shoes
Number of shoes
10.6 mm
Forefoot stack
27.7 mm

Drop

Calculating the difference between the heel and the forefoot of the On Cloud X 3 AD, we found that the shoe's drop is 9.2 mm. This is 1.2 mm taller than the officially stated 8 mm but is not critical.

On Cloud X Drop

This is quite tall for a training shoe as the typical drop ranges from 4 to 6 mm. Even road running shoes these days have an average drop of 8.7 mm.

But given that the On Cloud X 3 AD is not a tall shoe to begin with, we didn't feel like the heel was elevated that much. And yet, having a higher drop felt beneficial to us when walking or when heel striking during runs.

Test results
On Cloud X 3 AD 9.2 mm
Average 6.4 mm
Compared to 41 training shoes
Number of shoes
1.8 mm
Drop
13.4 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

The On Cloud X feels pretty dang firm (like most On Clouds, actually).

Pressing a durometer against the foam, we got a reading of 32.8 HA, which is 21% firmer than our lab-tested average.

On Cloud X Midsole softness

This is actually perfect for most exercises in the gym but is less than ideal for running. We recommend keeping the runs short (less than 5 miles) in the On Cloud X 3 AD unless you are used to a firmer ride.

And if you want softer cushioning for runs and jumps, we suggest the want a slick and stylish gym shoe that looks more like a sneaker.

Test results
On Cloud X 3 AD 32.8 HA
Average 27.8 HA
With its low forefoot stack and separate pods, the On Cloud X is very easy to bend.
Compared to 41 training shoes
Number of shoes
17.4 HA
Midsole softness (soft to firm)
41.0 HA

Insole thickness

Those willing to feel even more grounded in the On Cloud X can actually take out the insole and enjoy the difference.

We found that the insole in this shoe is much more padded than the average. At 5.7 mm, it is nearly 2 mm thicker than most trainers.

However, we didn't feel like it was a problem when working out.

On Cloud X Insole thickness
Test results
On Cloud X 3 AD 5.7 mm
Average 3.9 mm
Compared to 41 training shoes
Number of shoes
1.7 mm
Insole thickness
7.2 mm

Size and fit

Size

On Cloud X is true to size (292 votes).

Owners of this shoe, how does this shoe fit?

1 size small ½ size small True to size ½ size large 1 size large
Compared to 37 training shoes
Number of shoes
½ size small
Slightly small
True to size
Slightly large
½ size large

which are way more durable and tech-packed

With the On brand being notorious for its narrow-fitting shoes, we were especially meticulous about this measurement.

First, we measured the widest part of the toebox. Seeing 100.1 mm on the calliper was very reassuring. This is exactly the average of our lab-tested training shoes.

On Cloud X However, we didnt feel like it was a problem when working out
Test results
On Cloud X 3 AD 100.1 mm
Average 100.4 mm
Compared to 41 training shoes
Number of shoes
90.4 mm
which are way more durable and tech-packed
108.5 mm

Toebox width - big toe

The shoe doesn't get too narrow around the toes either. Measuring the width near the big toe at 78.5 mm, it is no different than the average.

Thus, we can confirm the brand's statement that the On Cloud X fits true to size.

On Cloud X oz / 268g
Test results
On Cloud X 3 AD 78.5 mm
Average 78.8 mm
Compared to 34 training shoes
Number of shoes
65.0 mm
Toebox width - big toe
89.4 mm

Stability

Lateral stability test

As soon as we put the On Cloud X 3 AD on, we knew that stability is the shoe's forte.

Tongue: gusset type.

Torsional rigidity

The On Cloud X 3 AD comes with a plastic Speedboard plate in its midsole, which adds the stiffness necessary for side-to-side stability.

Twisting the shoe in our hands, we assessed its torsional rigidity as 3 out of 5, where 5 is the stiffest.

Test results
On Cloud X 3 AD 3
Average 2.7
Compared to 41 training shoes
Number of shoes
1
Torsional rigidity
5

Top 18% most popular training shoes

We also made sure that the heel counter has a decent stiffness to it. Having enough firmness in this area is essential for ankle support.

Add a shoe.

This is just enough for most people but not so much for overpronators. We recommend these folks consider the Reebok Nano X4 Heck, it is even more expensive than the flagship Crossfit shoes like the.

Test results
On Cloud X 3 AD 3
Average 2.7
Compared to 41 training shoes
Number of shoes
1
Top 18% most popular training shoes
5

Midsole width - forefoot

The brand really made sure to provide the On Cloud X 3 AD with a wide and stable base.

Measuring the widest part of the sole in the forefoot, we found it to be 112.2 mm, which is a few millimetres wider than average. Impressive!

It really helped us feel planted for strength training, both bodyweight and with a moderate load. Having a wide landing surface also helped during box jumps.

On Cloud X Midsole width in the forefoot
Test results
On Cloud X 3 AD 112.2 mm
Average 110.6 mm
Compared to 41 training shoes
Number of shoes
101.0 mm
Midsole width - forefoot
117.9 mm

Midsole width - heel

The sole remains wide in the heel too. In the widest part, we found it to be 91.4 mm which is more than 4 mm wider than average!

On Cloud X Midsole width in the heel
Test results
On Cloud X 3 AD 91.4 mm
Average 87.3 mm
Compared to 41 training shoes
Number of shoes
76.5 mm
Midsole width - heel
97.4 mm

need a lightweight trainer the On Cloud X 3 AD is among the lightest in our catalogue

With its low forefoot stack and separate pods, the On Cloud X is very easy to bend.

It only required a force of 16.5N for us to bend the shoe to a 90-degree angle. Compared to other training shoes, this makes the Cloud 36% more flexible than average!

Having such a flexible forefoot in a gym shoe is essential for comfortable lunges and planks, among other exercises where you have to bend the foot a lot.

Test results
On Cloud X 3 AD 16.5N
Average 17.8N
If your training venue is hotter than the jungle, the Cloud X 3 is there to help.
Compared to 41 training shoes
Number of shoes
4.3N
Flexibility <> Stiffness
37.9N

Weight

According to the brand, the On Cloud X comes in at 8.6 oz (243g) per shoe.

We found it to be true, having weighed the shoe ourselves in a men's US size 9. The scale showed us just a couple of grammes heavier - 8.7 oz (248g).

This is incredibly light for a training shoe! Very few shoes on our list (minimalist excluded) can compete with that weight. We definitely felt very agile and manoeuvrable in this On Cloud trainer. It is barely felt on the foot!

On Cloud X Weight
Test results
On Cloud X 3 AD 8.75 oz (248g)
Average 10.76 oz (305g)
Compared to 41 training shoes
Number of shoes
6.38 oz (181g)
Weight
13.83 oz (392g)

Breathability

We experienced no issues with the lockdown either. Perhaps in part because of the shoe's embedded tongue.

It is not fully separated from the rest of the upper as in most shoes. We felt like this really helped to create a sock-like fit.

Breathability

Midsole softness soft to firm.

Despite its three-layer mesh, we found that the shoe keeps the interiors very well-ventilated. Pumping smoke through the upper, we were happy to see a lot of it coming out on the other side.

Track and XC.

Putting the shoe against a bright light, we could see which parts of the upper are most responsible for the ventilation. As you can see, the toebox mesh is very transparent.

Taking a closer look at the mesh through our microscope, we were able to see the shoe's breathability secret.

On Cloud X microscope

The middle mesh layer is made of really large ventilation pores, while the topmost layer has really thin threads.

On Cloud X microscope upper

Test results
On Cloud X 3 AD 4
Average 3.6
Compared to 41 training shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

Unfortunately, having multiple layers of mesh didn't make the On Cloud X more durable.

It was a huge disappointment to see how a £150 trainer got destroyed the moment our Dremel touched it. This made us rate the shoe's toebox durability as low as 1 out of 5.

Heel stack lab?

This is truly shocking because the Nike Metcon 8 (£130) was barely scratched after the same durability test. And we applied the same force (3.2N) and speed (10K RPM) in both cases.

Test results
On Cloud X 3 AD 1
Average 2.5
Compared to 30 training shoes
Number of shoes
1
Toebox durability
5

If your training venue is hotter than the jungle, the Cloud X 3 is there to help

The same happened to the shoe's heel padding. A very brief four-second encounter with our Dremel left this area completely torn. We also gave it a rating of 1 out of 5 (the lowest possible).

Of course, very few training shoes get away with a scratch after the Dremel test but we expected more from a shoe at such a high price point.

Test results
On Cloud X 3 AD 1
Average 2.5
Compared to 28 training shoes
Number of shoes
1
If your training venue is hotter than the jungle, the Cloud X 3 is there to help
5

Outsole hardness

The outsole seems to be doing better than the upper but still falls behind most gym shoes on our list.

Pressing a durometer against the rubber pods at the bottom gave us a reading of 82.8 HC. It is a little softer than average but not critically. We associate softer rubbers with faster abrasion.

However, if you plan to work out a lot outdoors, this is definitely not a great option. If you expect a long life from the On Cloud X 3 AD, limit its use to gym floors and rubber mats.

On Cloud X Outsole hardness
Test results
On Cloud X 3 AD 82.8 HC
Average 83.0 HC
With its low forefoot stack and separate pods, the On Cloud X is very easy to bend.
Compared to 41 training shoes
Number of shoes
71.0 HC
Outsole hardness
94.5 HC

Outsole durability

Applying our Dremel to the same rubber compound, we found that it left a little deeper dent compared to the average.

On Cloud X outsole durability

We used a tread gauge to measure the depth of the damage and it returned 1.15 mm. A little more than the average 1 mm. We believe that this is due to the slightly softer nature of this On shoe's rubber.

On Cloud X outsole durability test

Test results
On Cloud X 3 AD 1.1 mm
Average 1.1 mm
Compared to 26 training shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

Finally, we measured the thickness of the rubber compound with a calliper. It turned out to be 3 mm on the On Cloud X and is also thinner than the average 4 mm.

Given that the outsole is thinner, softer, and more prone to abrasion than the rest of our lab-tested trainers, we don't think that the outsole will last very long. The fact that it is not a full-length layer and is made up of separate pods doesn't help the situation.

All things considered, we are very much disappointed in the shoe's durability at this price point.

On Cloud X Outsole thickness
Test results
On Cloud X 3 AD 3.0 mm
Average 3.6 mm
Compared to 41 training shoes
Number of shoes
2.1 mm
Outsole thickness
5.1 mm

Misc

Grip / Traction

Having used the On Cloud X 3 AD for indoor workouts, we were quite happy with its grip on undemanding surfaces.

However, with its exposed foam and lack of treads, we wouldn't recommend testing its capacities in slippery conditions.

On Cloud X Lug depth

Reflective elements

The branding on the shoe's sides and heels is reflective and lights up in the dark.

On Cloud X Reflective elements
On Cloud X Reflective
Test results
On Cloud X 3 AD Yes

Tongue padding

The tongue of the On Cloud X 3 AD is not very thick compared to other trainers. We measured it at 4.4 mm whereas the average is 5.8 mm.

Add a shoe.

On Cloud X Tongue padding
Test results
On Cloud X 3 AD 4.4 mm
Average 5.4 mm
Compared to 41 training shoes
Number of shoes
1.0 mm
Tongue padding
10.4 mm

Tongue: gusset type

We experienced no issues with the lockdown either. Perhaps in part because of the shoe's embedded tongue.

It is not fully separated from the rest of the upper as in most shoes. We felt like this really helped to create a sock-like fit.

On Cloud X Tongue: gusset type
Test results
On Cloud X 3 AD Both sides (full)

Heel tab

There is no pull tab on the On Cloud X 3 AD but it is relatively easy to put on.

On Cloud X Heel tab
Test results
On Cloud X 3 AD None

Removable insole

The shoe's insole is very easy to remove. It will be especially beneficial for those who wish to add more plushness underfoot.

On Cloud X Removable insole
Test results
On Cloud X 3 AD Yes

Sustainable materials

A very welcome bonus for responsible buyers - 35% of the On Cloud X's materials are made up of recycled content.