On LightSpray Cloudboom Strike 2 review

After testing the On LightSpray Cloudboom Strike 2, we find it ideal for runners that:

• Enjoy trying the latest tech and want to experience the incredible LightSpray upper.
• Prefer a super shoe with full-length rubber coverage instead of the usual less-protected designs.
• Run marathons and strike with the forefoot, as our testing shows this shoe is fully tailored for that.
• Love On as a brand and simply want their best racer, no matter the price.

The LightSpray upper can deliver an incredible, seamless fit, but it simply doesn't work for everyone. Unlike traditional shoes, there's no way to fine-tune the fit. For a more classic upper, the ASICS Metaspeed Edge Tokyo or New Balance SuperComp Elite v6 are excellent options.

We also think heel strikers will find limited support, as this shoe is tailored more toward runners who land on the front half of the foot. Instead, check out the Nike Alphafly 3.

The On LightSpray Cloudboom Strike 2 has been designed to perform in the world's biggest marathons with On's elite athletes like Hellen Obiri, so it really needs to deliver when it comes to shock absorption.

And it does! We measured 157 SA in the heel and 136 SA in the forefoot, both of which are marathon-proof results by all means.

As On's top-tier competition shoe, it also gets the brand's best foam. We found an updated formula of Helion HF, the PEBA-based midsole foam that has powered On's super shoes for a while now.

The bounce is pretty good too at 76.0%, although it falls slightly short of the current best performers. It's a tiny difference, but one that may sting a little when you're paying such a high price. Maybe it's time to start thinking about aliphatic TPU...

What we all want from a competition shoe nowadays is to maximize the stack height while staying within the 40 mm limit, and the On LightSpray Cloudboom Strike 2 does this well. It doesn't max out the limit, but at 36.1 mm, we believe there's plenty of foam underfoot.

That's especially true after seeing its outstanding shock absorption results earlier. In our opinion, more foam isn't always better, and this shoe is a great example of why.

The forefoot also packs plenty of foam, with a final stack height of 33.4 mm.

Having that much foam in the front of the shoe results in a low drop of just 2.7 mm. This is the first indicator that the shoe is much better suited to forefoot strikers, and it won't be the last...

The On LightSpray Cloudboom Strike 2 has a soft feel and a very interesting midsole design, with a softer lower layer measuring 30.3 AC beneath the carbon plate and a removable drop-in insole also made from Helion HF that is slightly firmer at 36.0 AC on top of the plate. There's no conventional insole like in 99.9% of running shoes.

We then put the shoe in the freezer for 20 minutes and tested its softness again. It became just 1% firmer, which is an outstanding result and shows the amazing consistency from PEBA in cold conditions.

The On LightSpray Cloudboom Strike 2 features an aggressive, forward-rolling rocker that promotes fast, efficient transitions. In our experience, it creates a highly-assisted ride that feels noticeably different from a traditional racing shoe.

For this reason, it won't be the best choice for runners who prefer a more classic, natural ride.

We found a very interesting carbon-fiber Speedboard plate. After removing all the foam to expose the plate and reveal its true shape, we noticed that it's slightly narrower than usual. However, the familiar spoon-shaped transition from the midfoot into the forefoot is still there.

This narrower design contributes to less torsional rigidity, as we noticed during our runs. It's also fun to see that this plate feels like the complete opposite of the Energy Rim used in the ultra-light adidas Adizero Adios Pro Evo 3.

It was clear that the old CloudTec design wasn't a great fit for super shoes, so here we found a completely different approach with CloudTec Sphere that feels a bit like having Nike's Air Pods from the Alphafly, but made entirely from foam.

This design allows the forefoot foam to deform and spring back more effectively, or at least that's the theory. Either way, we love seeing brands experiment, take risks, and push footwear technology forward.

The LightSpray upper can't be fine-tuned with laces, so it's easy to see why On opted for a snug, sock-like fit. A loose fit would be a terrible match for this type of upper.

Our gel-based method is perfect for this construction, and we found that it immediately leans toward the narrower side, measuring just 91.5 mm in our first reading.

It's definitely super snug, measuring just 69.0 mm in the toebox. However, there's a big catch: the LightSpray material is ultra-minimal and doesn't create much pressure. Instead, it conforms to your foot, so runners who enjoy a secure fit will love it.

That said, this is the kind of upper that either works perfectly or doesn't work at all, with very little in between. And if it doesn't work for you, there's no way to fix the fit with an alternative lacing technique or other adjustments.

The toebox height is exceptionally generous at 33.1 mm, providing plenty of vertical space for the toes.

Therefore, marathoners can run long distances without worrying about a cramped toebox.

The On Cloudboom Strike 2 comes in two variants, with or without the LightSpray upper.

This is the defining feature of the shoe. LightSpray is an ultra-impressive technology where On sprays approximately 1.5 km of specialized filament using a robotic arm, creating the entire upper in one piece. It's very similar to adidas' Strung technology, but lighter and more race-oriented.

On states that this reduces a conventional upper's manufacturing process from around 200 steps to a single automated step. However, we have to be fair and point out that the cost also skyrockets, so we'll have to see whether this is a sustainable technology that can become more widely available over time.

With a 0.76 result in our traction test on wet concrete, the On LightSpray Cloudboom Strike 2 puts any doubts to rest and makes it clear that it's ready for rainy race days too.

We were really surprised to find such generous rubber coverage on a super shoe. Here in the lab, we're used to seeing very little rubber on most racing models, but On has managed to provide heel-to-toe coverage while keeping the shoe impressively lightweight.

It's also worth noting the massive central channel running from heel to toe, which helps keep the shoe centered while also shaving off some weight.

The carbon-fiber Speedboard creates a very stiff ride that works wonders for racing, but it may limit the shoe's potential for tempo training if you're thinking of using it for both purposes.

It's definitely more of a raw, race-focused super shoe.

The LightSpray version of the Cloudboom Strike 2 is around 15% lighter than the regular version.

And we have to say that clocking 5.9 oz (167g) is truly impressive considering the huge amount of foam in the midsole and the full-length rubber coverage, highlighting just how much the upper contributes to the overall weight of any running shoe.

This shoe is particularly interesting when it comes to stability, as it largely depends on where you land. For heel and early-midfoot strikers, we can only recommend it to runners with a perfectly neutral technique.

However, for those landing on the forefoot or just behind it, it's a completely different story, and you'll soon see why.

Given the carbon plate, it should come as no surprise that the Cloudboom Strike 2 is difficult to twist. However, it's not as rigid as some other super shoes, as we needed 14.6 Nm of torque to complete our test.

As expected from its minimalist construction, the LightSpray upper collapses under the slightest force and provides virtually no lateral support. It scores just 1/5 on our scale.

One of the features that sets the Cloudboom Strike 2 apart from most competitors in the super shoe arena is its massive forefoot, which we measured at 120.5 mm.

In this regard, it reminded us a lot of the Nike Alphafly 3, particularly in terms of the impressive stability it provides for forefoot strikers.

The heel is quite the opposite, measuring just 76.4 mm, while the midfoot area also features a brutal taper from the forefoot. Therefore, don't expect much stability in the rear of the shoe because it's simply not there.

We didn't predict the LightSpray upper to be particularly tough against our Dremel, and it certainly failed the test. With a score of just 1/5, the result still hurts a little, even if it was expected.

This excellent result (5/5) in the heel area was the ultimate confirmation that the LightSpray upper is far more durable on the inside than on the outside.

Super shoes sometimes use softer outsole rubber that wears down quickly, but that's not the case with the On LightSpray Cloudboom Strike 2. In our testing, it showed excellent resilience, with just 0.5 mm of wear!

With a thickness of 1.8 mm, we believe On has been quite generous with the Cloudboom Strike 2.

Other super shoe rivals come with thinner outsoles, so this should contribute to better durability.

The LightSpray upper doesn't glow at night, but here's an idea for you guys at On: what if you used reflective thread for the next LightSpray upper? That would look absolutely incredible at night.

The lack of laces brings simplicity and weight savings, but it also means you can't fine-tune the lockdown like you can with the regular Cloudboom Strike 2. Therefore, the LS is more dependent on getting the perfect size and having a foot shape that works well with this unique upper.

We measured the tongue (well, not really a tongue, but still...) at just 0.6 mm, which further highlights the extreme thinness of the LightSpray upper and shows just how incredible this technology is.

This is a sock-like upper that adapts to the shape of your foot, eliminating any chance of tongue sliding. It's perfect for runners who love the snug, foot-hugging fit popularized by the Alphafly from its very first version launched back in 2020.

The LightSpray technology is super cool, but we're not convinced it's capable of creating a functional finger-loop heel tab.

The On LightSpray Cloudboom Strike 2 comes with a noticeable price increase over the regular model, which is already an expensive running shoe. That said, it's actually cheaper than its predecessor, something that's increasingly rare nowadays. We believe this may be partly due to the cost of producing each LightSpray upper going down.

It's also worth noting that the build quality meets On's very high standards. Furthermore, the pair we purchased with our own money was manufactured in Switzerland, which sounds crazy nowadays and, in our view, adds extra value.