On Running Cloudflash

  • Posted on
  • By Ed Dailey
On Running Cloudflash

On September 10th, 2017, I competed in the Ironman 70.3 World Championships in Chattanooga, TN and wore my new On Running Cloudflash shoes for the first time at a race event. Prior to this shoe, I had been racing in the On Running Cloudracer since 2013. What follows is one part comparison, one part review of the new Cloudflash.

On Running Cloudflash

On Running, as most shoe companies tend to do, decided to change up their shoes for 2017. For some athletes, those decisions work out fine but it usually seems, at least from what I hear mostly, that the change is often bad for anyone who has been racing in the same model of shoe, for years, as I had been with the Cloudracer. So, it should come as no surprise that when I heard On was changing up their shoes this year, I was a little upset and really scared for what it meant for my race season especially since the change occurred 4 weeks before Ironman Canada and coming off a podium race at Ironman 70.3 Gulf Coast. And I needed new shoes going into Canada. I went to On’s website to see what was comparable to the “Racer” but that only caused more confusion. So I called On and spoke to a customer service representative. I explained my situation and she told me that I should switch to the Cloudrush. I ordered a pair of those, and when I received them, they seemed heavy and clunky. Not at all like my Racers but nonetheless, I thought the customer service rep had to know what she was talking about so I quickly broke them in and raced Ironman Canada. I had a bad race but it wasn’t entirely because of the shoe. The shoe had almost zero to do with it but I didn’t like them anyway. On a chance encounter with our On Running in-house sales rep, I talked to her about it and she explained that what I really should be running in, given my background and goals, is the Cloudflash. So, I ordered myself a pair of those.


When they arrived I instantly liked the feel and the weight of the shoe. They reminded me so much more of the Racer that I had been running in for years. It should also be noted that the “Flash” is the same shoe worn by the Olympians who raced for On during the 2016 Olympics before it was available to the general public. The two shoes have a completely different aesthetic but once they’re on the feet, they feel almost identical. The heel-toe offset is 5mm for both shoes and in the men’s size 8.5, the Cloudflash is 10g lighter due mostly because On removed the midsole of the shoe and attached the “cloud elements” directly to the Speedboard. The Speedboard is made of a super stiff material called Pebax (pronounced “pee-becks”) and is designed to return energy to the runner. The Flash upper is made of a new material that will shed water rather than hold it in the shoe which would make the shoe heavier when it got wet.

I received my new Cloudflash shoes about two weeks before 70.3 World Championships. It should be noted that I also had a pair of my original Cloudracers, broken in with a few miles of running, on stand-by in case the Flash wasn’t my shoe. I was able to get a few shorter training runs done in the Flash prior to the race. I really liked them quite a bit. They felt so much more like the Racer than the Rush did, and I was much more comfortable in them right from the start. With the Rush, I kept telling myself it would take a few running sessions to get use to them but it never came to fruition. I was constantly running in a shoe that I didn’t feel great about.


I should say, when I’m racing, I don’t really notice my shoes unless there’s a problem that makes me take notice. There’s just too much other stuff to think about and by race day, your shoes shouldn’t be a concern. But this race was different, it was on my mind because I was in a shoe I had never raced in before so I was a bit worried and I had already been asked to write this blog review so I was trying to take mental notes while focusing on the run before me. Overall, I really, really liked this shoe. It’s comfortable and light. I did notice that the shoe never felt waterlogged like the Racer did during a long race. I pee’d in the shoe several times and I poured a lot of water onto myself and I never once felt like the shoe was completely soaked and heavy. The new wrap-around heel cup, designed to mimic the seat of a race car, held my heel firmly in place even though I never untie or tie the shoe after tying them for the first time. With mid-sole removed, there is less material between the bottom of the foot and the ground and I expected to feel each impact a little more but I didn’t. My feet never felt like I had run a half marathon barefoot. There is one really big con to this shoe: when the ground was wet, the sole was slippery on toe-off. As I was running through aid stations the bottom of the shoe would get wet and after I cleared the aid station and went back to running at race pace, the toe would slip out from under me as the shoe came up at the back of the stride. While I don’t feel like it changed anything about the race or my time, it’s unsettling to feel your shoes slip out from under you while you’re running and it would certainly concern me if I were racing in the rain and trying to take a corner. I’m hoping that once the shoe gets worn in a little and the bottoms get scuffed up a bit, it’ll add some traction.


My final thoughts, the shoe is great. I guess I’m one of the lucky ones who doesn’t get burned when a shoe company revamps their models. I’ll know more in the coming weeks as I prepare for Ironman Los Cabos and I will update here following that race.