Our verdict

We found in the lab that the Cloudboom Max is On’s first true super trainer, with clearly improved energy return, a max-stack midsole, high-quality materials, and tank-like durability. Stability is also extremely high, especially for heel strikers. However, the firm ride, ultra-high price, and heavy weight turn it into a more heart-led than logic-led choice for most runners.

Pros

  • Excellent durability from top to bottom
  • Finally improved energy return
  • Stable as a table
  • High-quality materials
  • Solid traction
  • A real max-stack shoe
  • Generous rubber coverage
  • Upper mixes comfort and ventilation
  • Excellent lockdown

Cons

  • Heavier than most competitors
  • Very expensive
  • Shock absorption is lower than expected
  • Feels a bit too firm

Audience verdict

N/A
Not enough reviews yet

Who should buy

After running on it and dissecting the On Cloudboom Max in the lab, we can recommend it for:

  • On loyal runners who stick to the brand and want a super trainer with clearly improved energy return compared to the dull Cloudmonster Hyper.
  • Midfoot and forefoot strikers who prefer a flatter feel in the toe-off phase, and do not enjoy aggressive rocker designs.
  • Those looking for a premium daily trainer who don't mind paying extra for On’s design and materials.

On Cloudboom Max

Who should NOT buy

Sure, the Cloudboom Max is a super trainer, but is a heavy one. We found in the lab that this weight hurts pace changes, making it feel slow rather than lively. For a more versatile ride, the ASICS Megablast and the Saucony Endorphin Speed 5 are better picks.

We also think the high price is a serious drawback. In our view, it is hard to justify paying this much when faster-paced, budget-friendlier shoes like the Adidas Adizero EVO SL or the Brooks Hyperion Max 3 exist.

On Cloudboom Max parts

Cushioning

Shock absorption

The Cloudboom Max clearly follows a maximalist design, yet the shock absorption results from our lab were lower than expected for this category.

With 126 SA in the heel and 111 SA in the forefoot, cushioning is only decent and that gap may disappoint runners expecting top-tier numbers from a shoe with this name.

On Cloudboom Max Shock absorption heel
Heel
Forefoot
Test results
Cloudboom Max 126 SA
Average 129 SA
Compared to 303 running shoes
Number of shoes
52 SA
Shock absorption
173 SA

Energy return

Energy return has long been a weak point for many On daily trainers, as the brand often struggled to deliver a lively bounce in their training shoes. That changes with the On Cloudboom Max, which brings a noticeably more energetic and modern feel underfoot.

The shoe uses a dual-foam setup, with a top layer of PEBA-based Helion HF, the same material found in the Cloudboom Strike super shoe. In our testing, the higher amount of PEBA foam in the front of the midsole led to a clear split, with 61.9% energy return in the heel and an impressive 69.7% in the forefoot.

Heel
Forefoot
Test results
Cloudboom Max 61.4%
Average 58.5%
Compared to 300 running shoes
Number of shoes
38.0%
Energy return
83.0%

Heel stack

Adding Max to a shoe name today usually means pushing the heel stack as close as possible to 40 mm, or even beyond it. The On Cloudboom Max comes in just under that mark at 39.2 mm, but it still fits the max-stack category in our book.

That said, do not expect the extreme height or towering feel of shoes like the Nike Vomero Premium. The Cloudboom Max feels more like a slightly taller daily trainer, which for most runners is actually a much reasonable outcome.

On Cloudboom Max Heel stack
Test results
Cloudboom Max 39.2 mm
Average 34.8 mm
Compared to 495 running shoes
Number of shoes
22.5 mm
Heel stack
48.1 mm

Forefoot stack

We also measured the forefoot stack, which came in at exactly 30.0 mm. For runners who dislike strong ground feel, this offers reassurance, especially since the shoe pairs that height with a firm bottom foam layer and a plate sandwiched in between.

On Cloudboom Max Forefoot stack
Test results
Cloudboom Max 30.0 mm
Average 26.2 mm
Compared to 495 running shoes
Number of shoes
13.7 mm
Forefoot stack
38.5 mm

Drop

On lists an official drop of 8 mm, but our measurements came out slightly higher at 9.2 mm. This small difference does not change the ride, as the feel underfoot remains the same and the shoe still works well for all footstrike patterns.

On Cloudboom Max Drop
Test results
Cloudboom Max 9.2 mm
Average 8.6 mm
Compared to 495 running shoes
Number of shoes
-0.1 mm
Drop
16.1 mm

Midsole softness

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

A proper super trainer needs a premium foam, and On checks this box by using its Helion HF compound. This PEBA-based material is light and energetic, which is also expected at this price point.

When it comes to softness, we measured a moderate 18.6 HA. Even so, the ride feels noticeably firmer than that number suggests. Why?

On Cloudboom Max Midsole softness
Test results
Cloudboom Max 18.6 HA
Average 20.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 421 running shoes
Number of shoes
5.9 HA
Midsole softness (soft to firm)
36.1 HA

Secondary foam softness

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

The firm feel underfoot, which is common in many On daily trainers, comes from the secondary Helion HF foam. This bottom layer is TPEE-based and is meant to add stability and durability.

On Cloudboom Max Foam

That said, it may feel too firm for some runners. We measured it at 31.5 HA, and a bit more softness here would likely lead to a more comfortable running experience and improved shock absorption.

On Cloudboom Max Secondary foam softness
Test results
Cloudboom Max 31.5 HA
Average 22.8 HA
We use an average of four tests. The photo shows one of those tests.

Rocker

One area where On clearly separates itself from most brands is the rocker design, and it is a welcome choice. The Cloudboom Max keeps a moderate forefoot rocker despite being a max-stack shoe, preserving a more natural toe-off that many runners still prefer, instead of forcing an aggressive roll.

In contrast, the heel shows a much stronger curvature. This pronounced bevel helps heel strikers transition forward more smoothly and offsets the high stack.

On Cloudboom Max Rocker

Plate

Like most super trainers, the On Cloudboom Max uses a plate placed between two foam layers. In this case, the Speedboard is not carbon fibre but a fibreglass material, which is cheaper and noticeably more flexible.

The plate also features visible cutouts, as seen in our photo, instead of a solid sheet. This carved design allows extra bending through the midfoot and forefoot, helping the shoe feel less rigid than traditional full plates.

On Cloudboom Max Plate

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

Width / Fit

We created a detailed gel mould of the shoe’s interior, which showed a width of 94.6 mm. This sits slightly below the average of the running shoes we have tested so far.

However, we felt there was a bit more room in the forefoot, so we took a second measurement to get a clearer and more complete picture.

On Cloudboom Max Width / Fit
Test results
Cloudboom Max 94.6 mm
Average 95.1 mm
Compared to 250 running shoes
Number of shoes
88.5 mm
Width / Fit
101.1 mm

Toebox width

The toebox width measured 76.9 mm, which explains why the Cloudboom Max feels more forgiving than most other super trainers. While it is not foot-shaped like an Altra, it still provides plenty of room for natural toe splay.

On Cloudboom Max Toebox width
Test results
Cloudboom Max 76.9 mm
Average 73.2 mm
Compared to 250 running shoes
Number of shoes
66.7 mm
Toebox width
82.6 mm

Toebox height

There is also above-average vertical space in the toebox at 28.1 mm, allowing the toes to move more freely without feeling cramped.

For this reason, we see the Cloudboom Max as a solid option for runners looking for a maximalist shoe for long runs that offers generous internal volume.

On Cloudboom Max Toebox height
Test results
Cloudboom Max 28.1 mm
Average 27.1 mm
Compared to 250 running shoes
Number of shoes
22.0 mm
Toebox height
34.1 mm

Traction / Grip

Traction test

On asks a premium price for this shoe, which totally calls for high-quality materials across the board. Thankfully, the rubber delivers, as shown by our SATRA TM144 test result of 0.64, placing the shoe in the upper half of the lab and remaining reliable even on wet surfaces.

Test results
Cloudboom Max 0.64
Average 0.48
Compared to 294 running shoes
Number of shoes
0.11
Forefoot traction
0.85

Outsole design

On is not afraid to go against current trends, and the outsole of the Cloudboom Max is a clear example of that. Instead of a stripped-down layout, it uses broad rubber coverage across the heel and forefoot.

The exposed midsole is limited to a deep central channel and small carved sections that are unlikely to touch the ground on pavement. This offers strong midsole protection and durability, although the trade-off is clear, as this generous rubber layout inevitably adds weight.

On Cloudboom Max Outsole design

Flexibility / Stiffness

The high stack height of the Cloudboom Max results in a stiff ride, with a 19.1N reading in our test. This helps explain On’s choice of a fiberglass plate, as a carbon option would likely have made the shoe overly harsh for daily use.

On Cloudboom Max Flexibility / Stiffness
Test results
Cloudboom Max 19.1N
Average 15.3N
Compared to 297 running shoes
Number of shoes
3.9N
Flexibility <> Stiffness
28.5N

Weight

At 10.1 oz or 286g, weight is clearly not a strength of the Cloudboom Max. We definitely felt the shoe heavy, and it becomes noticeable when trying to increase pace, making the shoe feel sluggish and best suited for slower efforts.

On Cloudboom Max Weight
Test results
Cloudboom Max 10.1 oz (286g)
Average 9.3 oz (264g)
Compared to 496 running shoes
Number of shoes
5.3 oz (149g)
Weight
12.9 oz (366g)

Breathability

The engineered mesh of the Cloudboom Max is made from recycled polyester with TPU overlays, using ventilation holes to keep airflow consistent across the upper.

And consistency is exactly what we found. Using our smoke machine, the shoe earned a 4 out of 5 score, which feels well suited for summer runs while still offering enough protection for colder conditions. Just remember that sock choice remains critical in extreme weather.

Most of the ventilation is concentrated in the toebox and tongue, with an additional small vented section on the lateral side that we did not expect to see.

On Cloudboom Max Microscope

The material itself is not especially advanced for this price range.

On Cloudboom Max microscope mesh

While the overall quality is excellent and well executed, this is the same type of engineered mesh commonly found in shoes that cost much less.

Up front, the shoe feels less cushioned than expected given its weight, which stands out. In contrast, the heel area is very comfortable, thanks to plush foam that makes the heel counter feel soft and supportive.

Test results
Cloudboom Max 4
Average 3.7
Compared to 425 running shoes
Number of shoes
1
Breathability
5

Stability

Lateral stability test

The On Cloudboom Max felt very stable throughout our runs, and despite being a neutral shoe, it can suit runners with moderate support needs.

A wide footprint, high rigidity, the firmer Helion HF bottom layer, and the large external yellow clip wrapping the midfoot and heel all work together to keep the foot centred. It does not feel cloud-like, but the payoff is excellent control and stability.

Torsional rigidity

The fibreglass plate adds some torsional flex, scoring 4 out of 5 on our scale and avoiding the overly rigid feel common with carbon plates. This makes the shoe easier to live with during daily runs.

Test results
Cloudboom Max 4
Average 3.5
Compared to 474 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

On went all-in with heel counter stiffness, earning a 5 out of 5 in our manual test. Runners sensitive to firm counters may notice it, but the thick foam padding helps soften the feel and should work well for most users.

Test results
Cloudboom Max 5
Average 2.9
Compared to 458 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width - forefoot

Like most maximalist running shoes, the Cloudboom Max has larger dimensions than the average model.

However, the forefoot stays controlled at 117.2 mm, avoiding the oversized feel seen in shoes that push past 120 mm, which helps it avoid feeling bulky.

On Cloudboom Max Midsole width - forefoot
Test results
Cloudboom Max 117.2 mm
Average 114.4 mm
Compared to 496 running shoes
Number of shoes
102.2 mm
Midsole width - forefoot
126.9 mm

Midsole width - heel

It is at the heel where On clearly aimed for maximum stability, and it shows. A higher share of the firmer TPEE-based Helion HF, a very wide base measuring 101.5 mm, and the previously measured 5 out of 5 heel counter all work together to lock things down.

On Cloudboom Max Midsole width - heel
Test results
Cloudboom Max 101.5 mm
Average 90.7 mm
Compared to 496 running shoes
Number of shoes
70.8 mm
Midsole width - heel
106.6 mm

Durability

Toebox durability

The soft engineered mesh of the Cloudboom Max held up better than expected in our durability test thanks to the dual-layer design. A 3 out of 5 may not sound outstanding, but it still guarantees reliable durability for regular daily use.

Test results
Cloudboom Max 3
Average 2.6
Compared to 359 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

The heel padding is extremely comfortable while also delivering top-level durability. After using the Dremel, we found barely any damage at all, which justified a maximum score of 5 out of 5.

Test results
Cloudboom Max 5
Average 3.4
Compared to 353 running shoes
Number of shoes
1
Heel padding durability
5

Outsole durability

The rubber delivers both solid grip and strong durability, which is exactly the combination we want to see. After testing, we measured just 0.7 mm of rubber wear, an excellent result by any standard.

Test results
Cloudboom Max 0.7 mm
Average 1.1 mm
Compared to 337 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

With 2.7 mm of outsole thickness, the On Cloudboom Max leaves little doubt about durability.

On Cloudboom Max Rubber

While this is slightly below the average, the strong resilience of the rubber supports it, and we think On could have trimmed it even further for a lighter weight.

On Cloudboom Max Outsole thickness
Test results
Cloudboom Max 2.7 mm
Average 3.2 mm
Compared to 492 running shoes
Number of shoes
0.5 mm
Outsole thickness
6.1 mm

Misc

Insole thickness

On uses an insole similar to those found in super shoes, featuring an ultra-thin design that measures just 1.9 mm in thickness.

On Cloudboom Max Insole thickness
Test results
Cloudboom Max 1.9 mm
Average 4.5 mm
Compared to 490 running shoes
Number of shoes
1.5 mm
Insole thickness
7.8 mm

Removable insole

If you want even more stack height and cushioning, you can replace the stock insole with a thicker option. Interior volume will be reduced, but that should not be an issue for most runners given that the volume inside the toebox is generous.

On Cloudboom Max Removable insole
Test results
Cloudboom Max Yes

Midsole softness in cold (%)

By avoiding an EVA-based foam, the Cloudboom Max becomes only 6% firmer after spending 20 minutes in our freezer.

On Cloudboom Max Midsole softness in cold (%)
Test results
Cloudboom Max 6%
Average 24%
Compared to 420 running shoes
Number of shoes
0%
Midsole softness in cold
63%

Reflective elements

We found a small reflective On logo on the tongue, which earns a mention. However, we prefer the approach used in other On models like the Cloudsurfer 2, where the logo sits on the lateral side and is more visible to passing cars.

Test results
Cloudboom Max Yes

Tongue padding

The foot hold and lacing of the Cloudboom Max feel in line with its high price, using textured laces similar to those in super shoes and a hybrid eyelet chain that spreads pressure across the instep thanks to four lace loops.

On Cloudboom Max Laces

And this pressure-relieving design matters a lot because the tongue is extremely thin at 1.1 mm, following a weight-saving trend also seen in ASICS models.

On Cloudboom Max Tongue padding
Test results
Cloudboom Max 1.1 mm
Average 5.8 mm
Compared to 493 running shoes
Number of shoes
0.4 mm
Tongue padding
14.2 mm

Tongue: gusset type

As expected for a premium shoe, the tongue is fully gusseted. It is not easy to spot due to the black fabric, but it is there.

On Cloudboom Max Tongue: gusset type
Test results
Cloudboom Max Both sides (full)

Price

The On Cloudboom Max is very expensive—even by super trainer standards—and from a purely economic point of view, it is hard to justify. There are better options in terms of value or performance, so you need to be at peace with the usual premium that most On shoes carry.

Test results
Cloudboom Max $230
Compared to 496 running shoes
Number of shoes
£45
Price
£290

Heel tab

The heel design is very simple and does not include a pull tab. However, it clearly shows On’s focus on stability, with a shape that aims to keep the rearfoot well supported and centered.

On Cloudboom Max Heel tab
Test results
Cloudboom Max None