On's Cloudboom Strike became the brand's first genuinely competitive carbon-plated marathon racer when it arrived in 2024, and the new Cloudboom Strike 2, released in early 2026, is the most substantive update to the line since. It keeps the headline dimensions familiar — an approximately 39.5mm heel stack, a 3.2mm offset, and a full-length carbon plate — but changes enough inside the midsole and upper to justify a fresh look, particularly for runners who found the original a touch unforgiving at the back of a long race.
The biggest change is underfoot. On has moved to a higher-Pebax-content Helion Hyperfoam compound across the full midsole, while preserving the drop-in construction that lets you lift out a thick top layer for cleaning or to inspect the plate. In practice, the new foam feels more compliant at marathon pace, particularly in the forefoot, and appears to rebound more consistently over longer durations. Early lab data from independent reviewers places forefoot energy return in the low-to-mid 70% range, comfortably inside the peer group that includes the Nike Alphafly 4, the Adidas Adizero Evo SL Exo and the Asics Metaspeed Sky Paris 2.
The upper has been rebuilt around a lighter, more breathable engineered mesh that shaves noticeable weight from the overall package. Our UK 9 test pair weighed 212g, a saving of around 15g on the first Strike without any discernible loss of hold. The lacing has been reworked to sit flatter against the instep, and the heel counter is slightly softer, which will please runners who found the original's rim a little aggressive. The outer, the primary durability concern on the original, uses a denser rubber pattern under the forefoot and the lateral heel; at 120km of testing we saw less visible shear wear than on a first-generation Strike at the same distance.
The Strike 2 is most at home at marathon pace and slightly faster. The shoe encourages a forefoot-to-midfoot landing and rewards a high cadence, but it does not punish the heel-strike style as aggressively as the original. A 30km progression run from steady to half-marathon pace revealed a smoother transition and less plate snap than the Strike 1 at the changeover point, and a 10km threshold session felt predictable rather than twitchy. It is less overtly aggressive than the Alphafly 4 and less firm than the Adidas Adizero Evo SL Exo; within the super-shoe field, it now competes on feel rather than headline numbers.
At £270, it sits squarely in the current price band for a flagship racer and is unlikely to undercut the competition on spec-sheet value. But Strike 2 does what a second-generation super shoe should: it keeps the silhouette, irons out the weaknesses of the original, and gives runners who had settled into the Cloudboom Strike a reason to keep the platform through another marathon cycle. For newcomers to On's racing line, it is also now a credible first purchase rather than a sideways bet against the established Nike and Adidas options. A good, unshowy update — and, given On's trajectory, a signal that a more radical Strike 3 is probably still two years away.