Our verdict

We love the On Cloud X 3 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
  • Excellent ground feel
  • Stable platform
  • Flexible forefoot
  • Secure lockdown
  • Sustainable materials

Cons

  • No upper durability
  • Unreasonable price

Audience verdict

87
Great!
  • Top 11% most popular training shoes

Who should buy

In our opinion, the Cloud X 3 would be of great interest to those who:

  • want a slick and stylish gym shoe that looks more like a sneaker
  • need a lightweight trainer (the Cloud X 3 is among the lightest in our catalogue)
  • prefer firm platforms that are close to the ground

On Cloud X 3 review

Who should NOT buy

One major problem with the On Cloud X 3 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 X3 which are way more durable and tech-packed.

Another big concern is the shoe's durability. Based on our lab tests, the wear resistance of the Cloud X 3 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 3 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 3 Heel stack
Test results
Cloud X 3 25.5 mm
Average 24.7 mm
Compared to 40 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 Cloud X 3 felt quite steerable, quickly adjusting to changes in the foot position.

On Cloud X 3 Forefoot stack
Test results
Cloud X 3 16.3 mm
Average 18.4 mm
Compared to 40 training shoes
Number of shoes
10.6 mm
Forefoot stack
27.7 mm

Drop

The On Cloud X 3 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 3 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 Cloud X 3 unless you are used to a firmer ride.

And if you want softer cushioning for runs and jumps, we suggest the Nike Free Metcon 5.

Test results
Cloud X 3 9.2 mm
Average 6.3 mm
Compared to 40 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 3 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 3 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 Cloud X 3 unless you are used to a firmer ride.

And if you want softer cushioning for runs and jumps, we suggest the Nike Free Metcon 5.

Test results
Cloud X 3 32.8 HA
Average 27.7 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 40 training shoes
Number of shoes
17.4 HA
Midsole softness (soft to firm)
47.0 HA

Insole thickness

Those willing to feel even more grounded in the On Cloud X 3 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 3 Insole thickness
Test results
Cloud X 3 5.7 mm
Average 3.9 mm
Compared to 40 training shoes
Number of shoes
0.0 mm
Insole thickness
5.7 mm

Size and fit

Size

On Cloud X 3 is true to size (282 votes).

Owners of this shoe, how do you like the size?

Small True to size Large
Compared to 25 training shoes
Number of shoes
Small
True to size
Large

Toebox width - widest part

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 3 Toebox width at the widest part
Test results
Cloud X 3 100.1 mm
Average 100.3 mm
Compared to 40 training shoes
Number of shoes
90.4 mm
Toebox width - widest part
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 3 fits true to size.

On Cloud X 3 Toebox width at the big toe
Test results
Cloud X 3 78.5 mm
Average 78.4 mm
Compared to 33 training shoes
Number of shoes
65.0 mm
Toebox width - big toe
87.5 mm

Stability

Lateral stability test

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

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

Torsional rigidity

The Cloud X 3 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
Cloud X 3 3
Average 2.7
Compared to 40 training shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

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.

Based on our manual test of squeezing and pushing the collar, we rated this parameter as 3 out of 5.

This is just enough for most people but not so much for overpronators. We recommend these folks consider the Reebok Nano X3 as it has a stiffer and more padded heel collar.

Test results
Cloud X 3 3
Average 2.8
Compared to 40 training shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width - forefoot

The brand really made sure to provide the Cloud X 3 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 3 Midsole width in the forefoot
Test results
Cloud X 3 112.2 mm
Average 110.5 mm
Compared to 40 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 3 Midsole width in the heel
Test results
Cloud X 3 91.4 mm
Average 87.4 mm
Compared to 40 training shoes
Number of shoes
76.5 mm
Midsole width - heel
97.4 mm

Flexibility

Stiffness

With its low forefoot stack and separate pods, the On Cloud X 3 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
Cloud X 3 16.5N
Average 17.8N
We use an average of four tests. The video shows one of those tests.
Compared to 40 training shoes
Number of shoes
4.3N
Stiffness
37.9N

Weight

According to the brand, the On Cloud X 3 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 3 Weight
Test results
Cloud X 3 8.75 oz (248g)
Average 10.72 oz (304g)
Compared to 40 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

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

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.

Thus, the Cloud X 3 deserves a rating of 4 out of 5 for breathability.

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 3 microscope

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

On Cloud X 3 microscope upper

Test results
Cloud X 3 4
Average 3.6
Compared to 40 training shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

Unfortunately, having multiple layers of mesh didn't make the On Cloud X 3 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.

Why not add at least one protective overlay?

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
Cloud X 3 1
Average 2.6
Compared to 29 training shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

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
Cloud X 3 1
Average 2.6
Compared to 27 training shoes
Number of shoes
1
Heel padding durability
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 Cloud X 3, limit its use to gym floors and rubber mats.

On Cloud X 3 Outsole hardness
Test results
Cloud X 3 82.8 HC
Average 82.9 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 40 training shoes
Number of shoes
57.5 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 3 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 3 outsole durability test

Test results
Cloud X 3 1.1 mm
Average 1.1 mm
Compared to 25 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 3 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 3 Outsole thickness
Test results
Cloud X 3 3.0 mm
Average 3.6 mm
Compared to 40 training shoes
Number of shoes
0.0 mm
Outsole thickness
5.1 mm

Misc

Grip / Traction

Having used the Cloud X 3 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 3 Lug depth

Reflective elements

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

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

Tongue padding

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

And yet, we never experienced any lace bites or pressure points.

On Cloud X 3 Tongue padding
Test results
Cloud X 3 4.4 mm
Average 5.4 mm
Compared to 40 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 3 Tongue: gusset type
Test results
Cloud X 3 Both sides (full)

Heel tab

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

On Cloud X 3 Heel tab
Test results
Cloud X 3 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 3 Removable insole
Test results
Cloud X 3 Yes

Sustainable materials

A very welcome bonus for responsible buyers - 35% of the On Cloud X 3's materials are made up of recycled content.