On Cloudultra 2 Review

An in-depth review of the On Cloudultra 2 trail running shoe.

By on December 26, 2023 | Comments

Through the summer and fall, I was lucky enough to test the On Cloudultra 2 ($180) on my local trails in Fort Collins, Colorado.

The frequency illusion, also recognized as the Baader-Meinhof phenomenon or frequency bias, denotes a cognitive bias wherein individuals tend to encounter something more frequently subsequent to their initial discovery of it. For instance, it could involve hearing a song with greater regularity or seemingly spotting On Running shoes and apparel on everyone. This last example has been especially true at the airport of late.

But was I just noticing On more or was this brand suddenly taking off in the United States? I can’t say for certain, but I think it was the latter. This led me to a deep dive of their trail running shoes. I had to see what the hype was all about.

The On Cloudultra 2 has an actual weight of 10.2 ounces (289 grams) for a U.S. men’s size 9, and a 5-millimeter drop.

Overall the On Cloudultra 2 has small, incremental improvements from the original model in each part of the shoe. You can look back at our On Cloudultra review for more information on the original model, and read on for how we compare the two editions.

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On Cloudultra 2

The On Cloudultra 2. All photos: iRunFar/Bryon Powell

On Cloudultra 2 Upper

Crafted from partially recycled polyester in a stretchy knitted composition, the upper of the On Cloudultra 2 embraces a sock-like fit that extends just below the ankle. iRunFar testers struggled a bit with the narrow sock-like fit in the original On Cloudultra — read our On Cloudultra review for details. So, initially, I was skeptical of the sock-like fit, thinking it would be impossible to get my foot into the shoe, but I did not have that experience.

There is plenty of room to slide my foot in with ease. That being said, this design not only ensures a lightweight and airy sensation, but because of the generous stretch to the fabric around the ankle, it also simplifies the process of slipping into the shoe effortlessly. In addition to being stretchier, the fabric around the ankle is softer for improved comfort over the model’s first edition.

The Cloudultra 2 presents a smart feature — a small tab positioned at the forefront of the laces called FlipRelease. This handy feature, which was also on the original model, allows you to fine-tune the tightness of the laces without the need to pause and untie them, even in the midst of a race. This functionality allows you to adapt to changing foot conditions, seamlessly adjusting the shoe’s fit to accommodate any unexpected swelling. In essence, it’s akin to having a personal shoe tailor accompanying you on your journey.

That being said, I didn’t need to use the FlipRelease during my runs. Maybe I’m not running big enough mileage for this feature to actually warrant use? I blame that on working full-time, but that’s for a different review.

Or it could be that the Cloudultra 2 is a decently roomy shoe. At first, I didn’t like this shoe and wasn’t going to review it because the ankle/sock/heel situation felt too loose, but then, mid-run one day, I switched to using the furthest back lace eyelet, and boom, problems solved. No slipping around in the heel and plenty of room at my toes. This is the first time in all my years of running that I’ve ever used that lace eyelet — a first for everything. This experience is likely an indicator of how much the brand course corrected in this second edition from the tight, narrow fit of the original model.

The rubber that lines the seams and edges of the upper is incredibly tough. Even when I slid pretty far down a trail during a fall, my shoes were in perfect condition. I, however, was not. The double layer upper also proved to keep dirt out, but didn’t cause my feet to overheat. These are huge wins in my book.

On Cloudultra 2 - lateral view

A lateral view of the On Cloudultra 2.

On Cloudultra 2 Midsole

Like its predecessor, the On Cloudultra 2 showcases the plush Helion superfoam, designed to deliver not only a heightened sense of comfort, but also to prioritize performance. On says the Helion foam of the second version is softer than the first. The midsole also has the same TPU Speedboard of the first edition.

Of course, the now-visually-iconic midsole air channels of On shoes, what’s called CloudTec technology, are present on this shoe. The second version sports 11 air gaps, while the original edition had 13.

While I do admit these shoes are comfortable, there was a bit of a break-in period. I took a few walks in them before I went running. I was anticipating the holes in the midsole to be far more compliant than they were. This is probably a good thing — the structure of a shoe is important.

I felt like On crafted a shoe that balances comfort and structure really well. My experience was that the shoe was comfortable without being squishy. And while it didn’t have the “pop” that some other shoes have, the stiffness of the midsole provides a solid landing and taking-off platform that transferred energy well.

The shoe boasts a 5-millimeter drop. Personally, I thought this was fine, as my usual running shoes have a 6-millimeter drop. For comparison, the original On Cloudultra had an 8-millimeter drop.

On Cloudultra 2 - medial view

A medial view of the On Cloudultra 2.

On Cloudultra 2 Outsole

The defining Missiongrip outsole on the On Cloudultra 2, a true standout feature, is accompanied by an updated lug arrangement that the brand claims to amplify ground contact by 50% from the first version of this shoe. Overall, there’s one more uphill gripping lug at the toes, and the forefoot lugs are larger and thus there are less of them in this second version. There are also fewer midfoot lugs, but the heel lugs are basically unchanged.

This enhancement translates to a profound increase in traction over the prior edition, even on the most challenging and intricate trails. The outsole kept my feet feeling safe from sharp rocks or from slipping around on technical trails.

The lugs aren’t overly big, so if you find yourself running on dirt roads and pavement a decent amount, this shoe won’t be overkill.

Colorado experienced some crazy weather during my testing period, so I was able to use these in a variety of conditions. They performed really well on slick rocks — maintaining grip. They didn’t seem to accumulate a lot of mud on the outsole or in the midsole, but I wasn’t trying too hard to get into a serious bogging situation.

The outsole is still in fairly good condition, even after plenty of miles on them. In general, the whole shoe still looks really good, and it has a lot of life left in it.

On Cloudultra 2 - outsole

The outsole of the On Cloudultra 2.

On Cloudultra 2 Overall Impressions

I was sure that it was all marketing and great branding, but low and behold, I found myself excited to run in the On Cloudultra 2. I even started wearing them as casual shoes because they are one of the few trail shoes that look cool off the trails.

There is a reason I’ve been seeing On shoes everywhere: they’re really great shoes.

These shoes are perfect for mild to moderately technical trails. If you’re scrambling up rocks for an entire run, I’d get something with a bit more traction and a tighter fit. But for day-to-day use, the Cloudultra 2 is roomy without feeling sloppy, and comfortable without being plush.

I will note that I normally wear a women’s U.S. size 7.5, and this size in the Cloudultra 2 was too small for me. I went up a half size and found that the 8 fit perfectly.

Shop the Women's On Cloudultra 2Shop the Men's On Cloudultra 2

Call for Comments

  • Have you tried the On Cloudultra 2? What were your impressions?
  • Have you worn both the original On Cloudultra and this second edition? How do they compare for you?

[Editor’s Note: If you’re affiliated (i.e., an employee, ambassador, etc.) with a brand, please share your relation in each of your comments on this article. Thanks!]

Our Favorite Trail Running Shoes

Check out our Best Trail Running Shoes article to learn about our current favorite trail running shoes!

On Running Cloudultra 2 - top view

A top view of the On Cloudultra 2.

Reese Ruland

Reese Ruland enjoys spending her time exhausting herself in the mountains and desert, either on foot or by bike. She is a Pop Tart enthusiast, gear addict, science nerd, and mom to two French bulldogs, Loaf and Oatie. When she’s not out on some big adventure, she enjoys working with athletes on developing a healthy relationship with endurance sports and their bodies.