Tom's Guide Verdict
A comfortable, responsive shoe for easy running.
A good long run shoe
One of the most cushioned On running shoes
Lighter than other long-run shoes
Comes up a little small
Why you can trust Tom's Guide
I’ve never really understood the hype when it comes to On running shoes. In my years of testing the best running shoes, I’ve found them a little hard and a little flat. That said, other runners adore the CloudTec midsole, which is made of little open tubes or pockets of rubber that are designed to absorb the impact of each stride, then lock in place for an explosive toe off. The Swiss brand has quickly become one of the most popular running shoe brands on the market, so when it launched its latest innovation — the On Cloudmonster, I was keen to find out more.
Weight: 9.7oz (M), 8.1oz (W)
Widths: One width
The Cloudmonster sounds, and looks, a little silly, with its thick wedge of CloudTec. Monster by name and monster by nature, this shoe is huge, but it doesn’t feel it underfoot. Designed for easy runs and long training miles, On has gone for big energy return in its maximalist shoe. But how does it compare to other running shoes on the market? Read our On Cloudmonster review here to find out more.
On Cloudmonster review: Price and availability
The On Cloudmonster launches on April 31 online, and costs $169.99/£150. It’s available in sizes US 7-14 for men, and US 5-11 for women.
At the time of launch, the shoe comes in a navy colorway in the men’s version of the shoe, and a lilac colorway for the women’s model. It’s likely On will release more colorways in the near future.
On Cloudmonster review: Design and fit
The Cloudmonster is designed to feel cushioned underfoot with On’s latest cushioning material, called Helion. Made from a mix of two different foams (EVA and OBC), which still has a good amount of energy return. Underfoot, the shoe feels light, despite the higher stack height. Compared to similar easy running shoes, such as the Nike Invincible Run, the Cloudmonster is much lighter — weighing 9.7oz for a men’s US 8.5, compared to Nike’s 11oz.
Fit-wise, the shoe runs a little small and definitely feels shorter in the foot compared to other brands. I run in a UK 5, but buy casual shoes in a UK 4 (for the best fit, check out our guide on how to buy running shoes). Although I still had a thumb-width of room at the end of the shoe, it was tight, and if you’re between sizes, I definitely recommend going up half a size in these shoes to ensure they’re not pinching at the toe.
I tested these fresh out the box for two weeks, covering around 40 miles. I wore the shoes on a number of different training runs — from long, slow runs of around 10 miles, to speedier tempo sessions. I had no issue with the shoe rubbing or chafing.
The upper is pretty typical of On running shoes, with around 80% of the Polyester coming from recycled materials. The mesh tongue is lightweight for extra ventilation, and sits flat against the foot, without any uncomfortable bunching. The lacing system is a little like that used on the On Cloudvista — On’s newest lightweight trail running shoe, allowing for a comfortable fit across the top of the foot, without any hotspots.
As we’ve already mentioned, the midsole of On’s maximalist shoe contains On’s CloudTech pods, and more of them than ever before, to create the huge stack on the shoe. There’s also On’s Speedboard, which is a thin, snappy, thermoplastic layer, designed to help for a faster toe-off. And there’s also the Helion foam, designed to be lightweight and responsive underfoot. This all results in a good amount of energy return — the shoe feels bouncy underfoot, without feeling overly soft or plush.
Perhaps one of the most important design elements when it comes to the Cloudmonster is the rocker geometry of the shoe — something that has become more popular in running shoe designs of late. Often reserved for supershoes like those listed in our best carbon fiber running shoe roundup, it’s designed to propel you forward. On says its shoes are meant to keep your legs feeling fresh, not help you achieve a PR, and I enjoyed the sensation of the rocker, especially in the final miles of longer training runs.
One issue I often had with On running shoes is that stones would easily get stuck between the CloudTech pods, but this wasn’t an issue with the Cloudmonster. That said, they’re definitely best suited to the sidewalks, as there isn’t an awful lot of grip, and the stack height is pretty dramatic for uneven surfaces. I did test these on softer, gravel river paths as well as wet concrete and had no issue, but I definitely wouldn’t take them on trickier trails.
On Cloudmonster review: Performance
The On Cloudmonster comes into its own on long, easy miles, especially when your legs are tired after speed or strength sessions. I used these on long runs and easy runs, when I’d normally reach for my Nike Invincible Runs, or my Hoka Bondi 7’s, and found them just as comfortable, despite feeling a little firmer underfoot.
I’m a stompy runner, so often reach for shoes with a lot of foam, and was pleasantly surprised by the Cloudmonster. For the purposes of this review, I took them out for some faster tempo runs, and while they could pick up the pace when I needed them to, there’s definitely better shoes on the market for tempo sessions (I usually wear the Nike Air Zoom Tempo Next% or the New Balance FuelCell RC Elite v2 for speedier running).
I also tend to overpronate slightly at the end of my long runs, or when I’m running on tired legs, and I did find, perhaps due to the stack height, this happened more in the Coudmonster than it did in other shoes. This shouldn’t cause neutral runners much of an issue, but if you do struggle with overpronation, this might not be the shoe for you.
On Cloudmonster review: Verdict
Would I go as far as to say this is my favorite On running shoe to date? Absolutely. If you’re looking for a maximalist shoe that’ll get you through your long runs and your easy runs with a good amount of responsiveness and bounce, this is a strong contender.
That said, typical On fans, or runners who prefer a firmer, flatter, shoe, as well as those who tend to overpronate might find the heft of this shoe difficult to get along with. While it does feel stable underfoot, there isn’t any support to prevent the foot from collapsing inwards, and I’d probably opt for the Nike ZoomX Invincible Run, which is sold as more of a stability shoe.
For me, the On Cloudmonster will remain in the ‘easy ploddy miles’ side of my running shoe collection, but they were a pleasant surprise, and definitely a shoe I’ll return to often.
Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.