Our verdict

The On Cloudboom Echo 3 is the brand's first legitimate supershoe, and it doesn't disappoint in the performance department. Featuring a snappy carbon plate, bouncy Pebax foam, and a uniquely rockered design, we found this shoe is built for speed, pure and simple. Despite some downsides like its high cost and heavier weight, it's more than capable of standing its ground against the top-tier supershoes, something we've been keenly awaiting from On.

Pros

  • Well-cushioned for marathon distances
  • High-energy return from Pebax foam
  • Offers a responsive and bouncy ride
  • Exceptionally breathable upper
  • Excellent for 5K and 10K runs
  • Semi-gusseted tongue
  • A wonder for those with narrow feet
  • Made from premium-quality materials

Cons

  • Exorbitantly high price
  • Likely too narrow for most runners
  • Weight leans toward the heavier side

Audience verdict

84
Good!

Who should buy

The Cloudboom Echo 3 gets our seal of approval for:

  • Loyal On brand enthusiasts who've been eagerly awaiting the company's first true supershoe.
  • Runners with very narrow feet, looking for a performance shoe that offers a perfectly snug fit and feel.
  • Athletes in search of a high-drop marathon racer packed with world-class Pebax foam.

On Cloudboom Echo 3

Who should NOT buy

If you're mindful of your budget, it's tough to endorse the Cloudboom Echo 3. Priced at $290, it doesn't bring any distinct benefits to the table when compared to other supershoes like the Hoka Rocket X 2 or the Nike Alphafly Next% 2. Notably, we found these alternatives offer greater durability and a roomy fit.

The Echo 3 also falls short for individuals with medium to wide feet due to its exceptionally narrow design. For a more spacious fit, you'd be better off considering the Adidas Adizero Adios Pro 3. It offers similar weight characteristics, but in our view, is far more accommodating and, at least, twice as durable.

On Cloudboom Echo 3 parts

Breathability

When you're shelling out almost $300 for a racing shoe, you expect top-notch breathability, especially for those hot-weather races.

Fortunately, we found that On really delivered with the Cloudboom Echo 3—it scored a perfect 5/5 in our breathability test at the lab.

Our light test also revealed something crucial. We discovered that the airflow is not only great in the toebox but also in the midfoot.

This is a big deal for runners who sometimes have problems with the arches of their feet during hot races or long runs. Most other running shoes focus only on toebox ventilation.

On Cloudboom Echo 3 microscope

We took a closer look with our microscope and observed that On developed a thin engineered mesh with micro-ventilation holes, instead of a denser material with larger holes. This choice should improve durability.

On Cloudboom Echo 3

We also noticed that the upper of the shoe doesn't have any inner layer. Sure, this affects comfort a bit, but let's be honest, comfort isn't what we're seeking in a racing shoe. We're talking about a sports car here, not a luxury sedan!

Test results
Cloudboom Echo 3 5
Average 3.8
Compared to 234 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

We initially thought that the Cloudboom Echo 3 might not have great durability because of its thin, breathable mesh. But we at RunRepeat are all about testing shoes, not making guesses.

When we put the Cloudboom Echo 3 through its paces in a rigorous test against our Dremel, it turned in a good-enough performance!

You might think a score of 2/5 isn't great, but when you consider it in the context of all running shoes, it's actually a solid one. And given the shoe's excellent breathability, we think it's a truly commendable feat.

On Cloudboom Echo 3 Toebox durability
Test results
Cloudboom Echo 3 2
Average 2.4
Compared to 168 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

In most heel padding durability tests, competition shoes usually do well in, mainly because they often skimp on padding to save weight. But the Cloudboom Echo 3 broke that trend.

It ranks among the most comfortable marathon shoes we've evaluated, and it's this abundant heel padding that led to its below-average score. You just can't have it all!

On Cloudboom Echo 3 Heel padding durability
Test results
Cloudboom Echo 3 2
Average 3.2
Compared to 164 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

We next turned our attention to the outsole of the shoe, a critical area for many runners due to the quick wear and tear commonly seen in racing shoes.

On Cloudboom Echo 3 rubber

Compared to most other marathon shoes, the Cloudboom Echo 3 has significantly less exposed foam.

We measured the rubber hardness of this shoe at 74.9 HC using our durometer. This score is below average for running shoes in general, but it's exceptionally high for a racing shoe.

A higher score indicates a harder material, which, theoretically, should offer less grip but more durability. So, does it live up to this expectation? We're about to find out...

On Cloudboom Echo 3 Outsole hardness
Test results
Cloudboom Echo 3 74.9 HC
Average 80.5 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 285 running shoes
Number of shoes
52.1 HC
Outsole hardness
93.0 HC

Outsole durability

We put the outsole through a rigorous test with the Dremel, and the On Cloudboom Echo 3 fell short of delivering a strong performance.

The shoe's box states "Lifespan = four marathons", and our test confirms this claim. However, given the hardness of the rubber, we were surprised to measure a significant 1.3-mm indentation, which is quite a lot.

On Cloudboom Echo 3 Outsole durability
Test results
Cloudboom Echo 3 1.3 mm
Average 0.9 mm
Compared to 146 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

The outsole measures 2.4 mm, a thickness that adds extra weight and is unusually high for a racing shoe. However, this added thickness is essential for offsetting the shoe's lackluster durability.

On Cloudboom Echo 3 Outsole thickness
Test results
Cloudboom Echo 3 2.4 mm
Average 3.2 mm
Compared to 304 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

Weighing in at 7.9 oz or 225g, the Cloudboom Echo 3 isn't exactly a featherweight among the so-called supershoes.

We think On really needs to step it up in the next version. Just by opting for a better rubber on the outsole, they could shave off as much as an ounce.

On Cloudboom Echo 3 Weight
Test results
Cloudboom Echo 3 7.94 oz (225g)
Average 9.38 oz (266g)
Compared to 305 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

Probably, what most of you are keen to know is the stack height of the shoe.

On Cloudboom Echo 3 heel

Check out those strategically placed cutouts that brilliantly highlight the Echo's carbon plate.

In the case of the On Cloudboom Echo 3, it boasts a significant 38.6 mm in the heel, which is just 1.4 mm below from the maximum limit set by World Athletics (40 mm). So yes, this one is race-day legal!

On Cloudboom Echo 3 Heel stack
Test results
Cloudboom Echo 3 38.6 mm
Average 33.7 mm
Compared to 304 running shoes
Number of shoes
7.6 mm
Heel stack
45.7 mm

Forefoot stack

Next, we shifted our focus to the forefoot and took another measurement.

We gauged the stack height at this point to be 28.4 mm. It's pretty interesting to observe the spoon-like curve of the carbon plate, which is similar to what you'll find in the Nike Vaporfly Next% 2, although it can't be the same because Nike's design is patented.

On Cloudboom Echo 3 Forefoot stack
Test results
Cloudboom Echo 3 28.4 mm
Average 25.0 mm
Compared to 304 running shoes
Number of shoes
7.6 mm
Forefoot stack
36.9 mm

Drop

Racing shoes are generally trending towards lower heel-to-toe drops, like what you'll find in the ASICS Metaspeed Sky+. So it's quite intriguing to encounter a shoe with a much higher drop, like this one.

On advertises it as a shoe with a 9-mm drop, but we measured it at 10.2 mm, following official World Athletics guidelines.

This is especially good news for heel strikers who are looking for options with a higher heel-to-toe drop in a racing shoe. Up until now, the Adidas Adizero Adios Pro 2 (10.3 mm) was one of the few choices available. So for runners who prefer or require this type of shoe geometry, this option is really great.

On Cloudboom Echo 3 Drop
Test results
Cloudboom Echo 3 10.2 mm
Average 8.7 mm
Compared to 304 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

The insole is just 2.9 mm thick, a smart choice in our opinion.

Why is that? Because using a thinner insole allows for more foam in the shoe while still meeting World Athletics guidelines!

On Cloudboom Echo 3 Insole thickness
Test results
Cloudboom Echo 3 2.9 mm
Average 4.5 mm
Compared to 300 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

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

Here comes the star of the show! After much anticipation, On has finally rolled out a marathon shoe featuring its all-new Helion HF Pebax-based foam, giving you the highest energy return currently available. No more EVA, and no more big clouds!

But don't expect a super-soft experience with this racer. We measured its hardness at 23.5 HA, which is on the firmer side.

So, if you're a fan of a more solid feel underfoot, this shoe is fantastic. On the other hand, if you're in search of something extra cushy, you might want to look at other options like the Saucony Endorphin Pro 3.

On Cloudboom Echo 3 Midsole softness
Test results
Cloudboom Echo 3 23.5 HA
Average 21.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 232 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Difference in midsole softness in cold

After chilling the shoe in the freezer for 20 minutes, we ran the softness test once more. This time, we observed a slightly higher reading of 25.6 HA.

This is an astonishingly low increase of just 8.9%, which is downright impressive compared to other running shoes.

However, it's not really a shocker for us. In our advanced guide in thos topic, we've already shared how amazing Pebax foams are, especially in cold weather.

On Cloudboom Echo 3 Midsole softness in cold
Test results
Cloudboom Echo 3 8.9%
Average 25.5%
Compared to 231 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Stability

Lateral stability test

When it comes to stability, don't get your hopes up. This is a racing shoe that doesn't offer much in that department, except for the carbon plate.

If you're a neutral runner, you'll likely feel comfortable in these. But if you have issues with pronation or supination, you might want to look at a different type of shoe, like the ASICS Superblast.

Torsional rigidity

With an extremely rigid carbon plate, we fully expected a perfect score of 5/5 in this test, and that's exactly what the Cloudboom Echo 3 gave us. It took a lot of force for us to twist it.

Test results
Cloudboom Echo 3 5
Average 3.2
Compared to 283 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The heel counter is somewhat structured, which is uncommon for racing shoes.

This makes it a solid pick for folks who need extra heel support. After our tests, we gave it a 2/5.

Test results
Cloudboom Echo 3 2
Average 2.8
Compared to 267 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

The first thing that really catched our attention when we picked up the Echo 3 was its narrow design. Even the forefoot, which is typically wider in racing shoes, measures only 107.0 mm.

On Cloudboom Echo 3 Midsole width in the forefoot
Test results
Cloudboom Echo 3 107.0 mm
Average 113.7 mm
Compared to 305 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

What's truly astonishing is the heel width. Measuring just 78.1 mm, this shoe is virtually off-limits for heel strikers with stability issues.

We suspect that On initially intended for this shoe to be wider but had to slim down the design to keep the weight low.

On Cloudboom Echo 3 Midsole width in the heel
Test results
Cloudboom Echo 3 78.1 mm
Average 90.5 mm
Compared to 305 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

Just like in the torsional test, a shoe with a carbon plate consistently scores high in the 90-degree bend test.

We had to exert significant effort, applying 48.5N of force to bend the shoe to the desired angle.

Test results
Cloudboom Echo 3 48.5N
Average 29.2N
We use an average of four tests. The video shows one of those tests.
Compared to 287 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

After another 20-minute siesta in the freezer, we ran the same test again. This time, we had to apply 57.1N of force to bend the shoe to the same measurement point.

This 17.8% increase is pretty amazing and just goes to show how awesome Pebax foams perform in cold weather. In comparison, the average EVA midsole's score would be at least twice as high.

Test results
Cloudboom Echo 3 17.8%
Average 35.9%
Compared to 287 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Toebox width at the widest part

The slim design of the midsole hinted at a narrow upper, but we confirmed it with exact measurements.

Our tests revealed a width of 94.7 mm, solidifying our initial impression. This shoe is decidedly not crafted for those with wide feet.

On Cloudboom Echo 3 Toebox width at the widest part
Test results
Cloudboom Echo 3 94.7 mm
Average 98.4 mm
Compared to 305 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

The same issue applies to the big toe area, measuring just 73.5 mm wide.

For anyone without narrow feet, this shoe is likely to cause blisters in races. We don't think that even going up a size would fix this problem.

On Cloudboom Echo 3 Toebox width at the big toe
Test results
Cloudboom Echo 3 73.5 mm
Average 78.2 mm
Compared to 179 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

The tongue is semi-gusseted, something we truly appreciate and one that not all racing shoes provide. This feature helps prevent unwanted movement, especially crucial when you're running at top speed.

On Cloudboom Echo 3 Tongue: gusset type
Test results
Cloudboom Echo 3 One side (semi)

Comfort

Tongue padding

The tongue is a surprisingly plush 2.3 mm thick.

On Cloudboom Echo 3 laces

The laces are one of the thinnest we've ever seen

Though this might seem low compared to most running shoes, it's actually quite generous when stacked up against its direct competitors:

On Cloudboom Echo 3 Tongue padding
Test results
Cloudboom Echo 3 2.3 mm
Average 5.6 mm
Compared to 302 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

On chose to skip the heel tab on the Cloudboom Echo 3, a smart move aimed at shaving off extra weight wherever possible!

On Cloudboom Echo 3 Heel tab
Test results
Cloudboom Echo 3 None

Removable insole

The insole isn't glued down, a definite plus. While some brands choose to glue the insole to prevent shifting, this design offers more flexibility, although you'll need custom orthotics—forget about OTC—given the narrow design of this shoe.

On Cloudboom Echo 3 Removable insole
Test results
Cloudboom Echo 3 Yes

Misc

Reflective elements

The Echo 3 doesn't feature any reflective elements, but let's be honest—those are seldom missed in a racing shoe, aren't they?

On Cloudboom Echo 3 Reflective elements
Test results
Cloudboom Echo 3 No