Our verdict

84
Great
  • Cross-training/HIIT 86
  • Cardio 90
  • Weightlifting 62
The On Cloud X 5 is a versatile gym generalist with a clean silhouette that easily doubles as a day-to-day sneaker. More cushioned than the average trainer, it accommodates fitness classes and cardio sessions much better than lifting. But this time around, our lab tests showed noteworthy improvements in the X 5's stability, grip, and forefoot flexibility, making it a more functional cross-trainer than the X 4. Yet, the shoe's high price remains one of the shoe's biggest stumbling blocks.

Pros

  • Excellent cushioning for high-impact workouts
  • Great forefoot flexibility for natural foot bending
  • Reliable traction on gym surfaces
  • Improved stability and lateral support
  • Better padded interiors
  • Durable outsole rubber
  • Comfortable medium-width fit

Cons

  • Too expensive for its use case
  • Limited breathability
  • Not for serious strength training

Who should buy

In our opinion, the On Cloud X 5 could make a solid match for people who:

  • mostly focus on cardio, fitness classes, and light-to-moderate strength training
  • prioritize impact protection over stability and groundedness
  • want a sleek trainer that transitions into everyday activities

On Cloud X 5 review

Who should NOT buy

We wouldn’t choose the Cloud X 5 for a lifting-focused routine with heavy squats and deadlifts. You would need a sturdier option, such as the adidas Dropset 4 or the Nike Metcon 10.

This trainer from On is also difficult to recommend to people prioritizing great value for money. There are plenty of shoes that offer performance comparable to, or even better than, the Cloud X 5, but at a much more accessible price point. For example, the Nike Free Metcon 7.

On Cloud X 5 lab test

Cushioning

Shock absorption

Built on a taller platform, the On Cloud X 5 offers more cushioning for cardio and fitness classes than the average cross-trainer.

With a high shock absorption of 107 SA in the heel and 91 SA in the forefoot, it offers even more protection than the previous Cloud X 4, minimizing fatigue in the muscles and tendons during high-impact exercises.

On Cloud X 5 Shock absorption heel
Heel
Forefoot
Test results
Cloud X 5 107 SA
Average 83 SA
Compared to 37 training shoes
Number of shoes
12 SA
Shock absorption
133 SA

Energy return

However, the Cloud X 5 feels much flatter than its predecessor, offering virtually no springback during push-off. Our energy return test showed very low measurements of 47% in both the forefoot and the heel of this On shoe, proving that its cushioning is far from bouncy.

But in the context of training shoes, this is actually good news, as the duller ride makes the new iteration feel more planted.

Heel
Forefoot
Test results
Cloud X 5 47.3%
Average 55.5%
Compared to 37 training shoes
Number of shoes
32.0%
Energy return
80.0%

Heel stack

Much like the previous version, the Cloud X 5 stands above the average trainer with a tall heel stack of 31.0 mm.

This allows the shoe to pack more cushioning but makes it less preferred for agility drills and strength training, where a more grounded setup is typically preferred.

On Cloud X 5 Heel stack
Test results
Cloud X 5 31.0 mm
Average 24.2 mm
Compared to 48 training shoes
Number of shoes
6.9 mm
Heel stack
36.2 mm

Forefoot stack

Our caliper also showed that the X 5's forefoot stack grew by 3 mm, reaching 24.3 mm.

This created a thicker buffer under the ball of the foot and the toe joints, and is a welcome update for people who need more cushioning in this area.

On Cloud X 5 Forefoot stack
Test results
Cloud X 5 24.3 mm
Average 17.8 mm
Compared to 48 training shoes
Number of shoes
6.8 mm
Forefoot stack
25.0 mm

Drop

Assessing the difference in stack heights, we found that the new version's heel-to-toe drop came down from 8.9 mm to 6.7 mm.

Although it's not a radical change, we are glad to see a moderate offset in a training shoe, as it contributes to a more stable underfoot experience.

On Cloud X 5 Drop
Test results
Cloud X 5 6.7 mm
Average 6.4 mm
Compared to 48 training shoes
Number of shoes
0.0 mm
Drop
12.6 mm

Midsole softness

Note: Low measurement: softer. High measurement: firmer.

We couldn't help but notice that the new Cloud X 5's platform got harder. And even though the CloudTec pods create some compression, the overall experience stays on the firm side.

Our durometer measurement confirmed this observation. The new Helion foam registered 56.1 AC, which is 15% firmer compared to the average training shoe foam.

On Cloud X 5 Midsole softness
Test results
Cloud X 5 56.1 AC
Average 49.0 AC
Compared to 30 training shoes
Number of shoes
33.3 AC
Soft ←→ Firm
94.1 AC

Size and fit

Size

Owners of this shoe, how does it fit?

1 size small ½ size small True to size ½ size large 1 size large

Internal length

Note: Our testing shows that internal length is not a great measure of fit. But, as many users have requested this specific test, we've decided to add it for those interested.
On Cloud X 5 Internal length
Test results
Cloud X 5 271.7 mm
Average 268.8 mm
Compared to 35 training shoes
Number of shoes
252.8 mm
Internal length
276.3 mm

Width / Fit

Looks like On kept the same approach to the fit and sizing of the Cloud X 5, as the new version showed nearly identical measurements to its predecessor.

After taking a solid gel cast out of the shoe and measuring it with a caliper, we recorded 95.3 mm at its widest point. This is perfectly on par with the category average and the typical medium-width fit.

On Cloud X 5 Width / Fit
Test results
Cloud X 5 95.3 mm
Average 96.2 mm
Compared to 30 training shoes
Number of shoes
90.0 mm
Width / Fit
101.4 mm

Toebox width

The shoe's toebox also aligned with the average medium width, measuring 73.7 mm. There is no aggressive tapering here.

On Cloud X 5 Toebox width
Test results
Cloud X 5 73.7 mm
Average 73.4 mm
Compared to 30 training shoes
Number of shoes
65.1 mm
Toebox width
81.0 mm

Toebox height

We didn't experience any pressure on top of the toes either, thanks to the shoe's toebox height of 25.9 mm.

Its soft, stretchy mesh also contributes to a comfortable, non-restrictive experience.

On Cloud X 5 Toebox height
Test results
Cloud X 5 25.9 mm
Average 27.2 mm
Compared to 30 training shoes
Number of shoes
22.1 mm
Toebox height
34.0 mm

Traction / Grip

Traction test

Although it's not visually apparent, the shoe's outsole rubber may also have been updated to a grippier compound. Measuring the Cloud X 5's friction coefficient, we recorded a notably higher reading of 0.33 compared with its predecessor (0.25).

On par with the training shoe average, it inspires confidence on common gym surfaces like rubber mats, hardwood floors, plywood boxes, and machine pedals.

Test results
Cloud X 5 0.33
Average 0.34
Compared to 35 training shoes
Number of shoes
0.18
Forefoot traction
0.53

Outsole design

The shoe's segmented outsole design remained unchanged, featuring separate pods to complement the CloudTec midsole.

Only the forefoot and heel pods are covered in rubber to provide grip where it's most needed, while keeping the Cloud X 5 light and pliable.

On Cloud X 5 Outsole design

Flexibility / Stiffness

Increased flexibility is one of the most noteworthy updates in the On Cloud X 5. With the Speedboard removed from its midsole and its flex grooves deepened, the shoe proved a whopping 30% more flexible than its predecessor!

On Cloud X 5 forefoot flex

Requiring only 10.2N to bend by 30 degrees instead of 14.8N, the X 5 made lunges, planks, burpees, split squats, and floor exercises feel much more natural.

On Cloud X 5 Flexibility / Stiffness
Test results
Cloud X 5 10.2N
Average 10.3N
Compared to 36 training shoes
Number of shoes
2.5N
Flexible ←→ Stiff
19.3N

Weight

True to its product specs, the Cloud X 5 weighs 10.1 oz (286g) in a men's US size 9. This is slightly heavier than the X 4 (9.5 oz/268g) but still within the category average.

The extra grams are most likely due to the shoe's increased forefoot stack, but overall, we didn't feel weighed down by this on the trainer, even during fast-paced cardio and treadmill sessions.

On Cloud X 5 Weight
Test results
Cloud X 5 10.1 oz (286g)
Average 10.7 oz (302g)
Compared to 48 training shoes
Number of shoes
7.7 oz (218g)
Weight
13.8 oz (392g)

Stability

Lateral stability test

Even though the stiff Speedboard was removed from the Cloud X 5, we found that the new version feels a bit more stable overall.

On Cloud X 4 vs X 5

The firmer foam, the raised midsole sidewalls that put the foot deeper into the cradle, and the wider platform all contributed to the shoe's increased lateral support.

But please note that even with all these updates, we still don't find the On Cloud X 5 a viable option for serious strength training. It can handle light-to-moderate exercises with dumbbells, kettlebells, and even some barbell work (up to 135–225 lb/60–100 kg), but nothing heavier.

Its cushioned and slightly rockered sole doesn't help with stability for squats and deadlifts either.

Torsional rigidity

Paradoxically, the absence of the Speedboard plate didn't make the Cloud X 5 less torsionally rigid. Given all the other updates to the shoe's construction, it even got a little harder to twist!

Measuring the torque required to twist this trainer by 10 degrees in both directions, we got a standard reading of 12.8 Nm. But it's not as sturdy and structured as the more lifting-oriented trainers like the Nike Metcon 10 (16.6 Nm).

On Cloud X 5 Torsional rigidity
Test results
Cloud X 5 12.8 Nm
Average 13.7 Nm
Compared to 19 training shoes
Number of shoes
5.1 Nm
Flexible ←→ Rigid
18.8 Nm

Heel counter stiffness

We also found the shoe's heel counter more substantial than that of the X 4's and rated its stiffness a higher 4 out of 5. And a thicker collar padding further strengthened the shoe's heel hold.

Test results
Cloud X 5 4
Average 2.8
Compared to 48 training shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width - forefoot

With a much broader forefoot width of 116.9 mm, the Cloud X 5 offers more extended contact points with the floor than the X 4. What's more, it is also one of the widest midsoles in the category.

On Cloud X 5 Midsole width - forefoot
Test results
Cloud X 5 116.9 mm
Average 112.1 mm
Compared to 48 training shoes
Number of shoes
103.8 mm
Midsole width - forefoot
117.9 mm

Midsole width - heel

The shoe's heel also inspires plenty of confidence, showing an above-average reading of 90.6 mm at its widest area.

On Cloud X 5 Midsole width - heel
Test results
Cloud X 5 90.6 mm
Average 86.9 mm
Compared to 48 training shoes
Number of shoes
71.1 mm
Midsole width - heel
95.9 mm

Durability

Toebox durability

We are pleased to see an improvement in the upper durability of the Cloud X 5, but we still couldn't rate it any higher than 3 out of 5 given the visible damage left by our Dremel.

Test results
Cloud X 5 3
Average 2.7
Compared to 43 training shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

The textile lining inside the shoe also demonstrated decent wear resistance, keeping the heel padding durability score at 3 out of 5. But the good news is that it is significantly better than the interior lining of the X 4!

Test results
Cloud X 5 3
Average 3
Compared to 41 training shoes
Number of shoes
1
Heel padding durability
5

Outsole durability

We also observed a tangible improvement in the shoe's outsole durability! The new rubber didn't allow our Dremel to dig any deeper than 0.7 mm, proving the compound to be more hard-wearing than both the X 4 and the category average.

Test results
Cloud X 5 0.7 mm
Average 1.1 mm
Compared to 39 training shoes
Number of shoes
0.0 mm
Outsole wear (Good ←→ Bad)
2.0 mm

Outsole thickness

Given the impressive durability result above, we aren't concerned that the shoe's rubber layer is a little thinner than average at 2.8 mm.

On Cloud X 5 Outsole thickness
Test results
Cloud X 5 2.8 mm
Average 3.5 mm
Compared to 48 training shoes
Number of shoes
0.0 mm
Outsole thickness
5.1 mm

Comfort

Breathability

With its reconfigured open mesh upper, the Cloud X 5 lost some of the previous model's insane ventilation.

It still does a decent job of keeping the foot aerated, but not quite as effectively, lowering our breathability score to only 2 out of 5. Because of this, it wouldn't be our first choice for breaking sweat on a hot summer day.

On Cloud X 5 mesh under microscope

Test results
Cloud X 5 2
Average 3.5
Compared to 48 training shoes
Number of shoes
1
Breathability
5

Tongue padding

As promised by the shoe's product description, the Cloud X 5 features more padding in both its collar and tongue. The latter doubled in thickness, going from only 4.1 mm to 8.1 mm. This made the shoe's step-in feel cozier and the fit more secure.

On Cloud X 5 Tongue padding
Test results
Cloud X 5 8.1 mm
Average 6.0 mm
Compared to 48 training shoes
Number of shoes
1.2 mm
Tongue padding
15.2 mm

Tongue: gusset type

The shoe's tongue remains gusseted, which not only prevents it from shifting and sliding during movement but also contributes to a secure lockdown.

On Cloud X 5 Tongue: gusset type
Test results
Cloud X 5 Both sides (full)

Insole thickness

The insole remained moderately padded, measuring 4.5 mm at the heel. It offers a touch of padding on top of the Cloud X 5's otherwise firm midsole.

On Cloud X 5 Insole thickness
Test results
Cloud X 5 4.5 mm
Average 4.0 mm
Compared to 48 training shoes
Number of shoes
0.0 mm
Insole thickness
7.2 mm

Removable insole

For those who need more targeted underfoot support or cushioning, the shoe's removable insole can be swapped for an alternative insert.

On Cloud X 5 Removable insole
Test results
Cloud X 5 Yes

Heel tab

There are no pull tabs to assist with the on-and-off in this On trainer.

On Cloud X 5 Heel tab
Test results
Cloud X 5 None

Misc

Reflective elements

All of the On logos on the Cloud X 5 proved to be reflective in our dark room test.

Test results
Cloud X 5 Yes

Price

As one of the most expensive training shoes in our catalog, we doubt the On Cloud X 5 offers equally good value for money. It is a comfortable and functional trainer indeed, but its functionality is too limited considering the competition.

On Cloud X 5 Price
Test results
Cloud X 5 $160
Compared to 48 training shoes
Number of shoes
£65
Price
£180