On Cloudspike Amplius 2 review

After testing it both on the track and in the lab, we believe the On Cloudspike Amplius 2 is a great match for:

• Track athletes with wide feet who struggle to find enough room in most elite spikes.
• Runners who find traditional spikes too narrow or unstable and prefer a broader platform underfoot.
• Fans of On super shoes who want a similar experience for track racing with the same Helion HF foam.

We know that many athletes prefer the propulsive feel of a full-length carbon plate, but On chose a different approach with the Cloudspike Amplius 2. If that's a must-have feature for you, we recommend looking at options such as the New Balance FuelCell SuperComp LD-X v3 or the Nike Dragonfly 2 Elite.

We also found that the Amplius 2 offers a roomier fit than most elite spikes. Therefore, runners who prefer an especially snug fit may be better served by the ASICS Metaspeed LD 2.

The Cloudspike Amplius 2 was designed primarily for elite athletes competing in events such as the 5,000m and 10,000m, so we weren't surprised to find a stack height approaching the World Athletics limit.

Since 2024, the maximum allowed stack has been 20 mm, and On pushed close to that threshold with an 18.2 mm measurement.

The forefoot comes in at 18.8 mm, moving even closer to the current race limit. This result aligns perfectly with our expectations and places the Amplius 2 alongside other premium long-distance spikes that maximize cushioning within the regulations.

The On Cloudspike Amplius 2 delivers a classic long-distance spike ride with a nearly flat geometry and a measured drop of -0.6 mm.

However, as we often point out with track spikes, the classic heel-to-toe drop matters less than in road shoes since most athletes land on the midfoot or forefoot rather than the heel.

What we found here is particularly interesting. Most brands tend to use firmer foams in their track spikes than in their road shoes, but On has taken the opposite approach.

While the company is known for using relatively firm midsoles across much of its road running lineup, the Cloudspike Amplius 2 surprised us with a notably soft foam for a spike, measuring just 37.0 AC on our Asker C durometer.

We also found that On didn't cut corners with the midsole compound. The shoe features Helion HF, the brand's flagship foam and the same high-performance material found in premium super shoes such as the On Cloudboom Strike.

On opted for a more forgiving approach by incorporating a midfoot shank that enhances stability and arch support, following a concept similar to the one adidas used in the Adizero EVO SL.

As a result, we believe the Amplius 2 stands out as an appealing option for runners who prefer to avoid the ultra-rigid sensation often associated with full-length carbon plates.

To compare the fit of the Cloudspike Amplius 2 against its competitors, we followed our standard testing protocol: filling the toebox with a special gel, allowing it to set in the fridge, and then taking three separate measurements.

The first measurement confirmed exactly what we noticed during our test runs. At 92.7 mm, the Cloudspike Amplius 2 offers a noticeably roomier fit than most of its direct rivals, delivering more space through the forefoot than is common in the track spike category.

The second measurement, taken at the widest part of the toebox, also came in above average at 72.9 mm. Based on our findings, we believe the Cloudspike Amplius 2 is one of the best elite-level spikes currently available for runners with wide feet.

We found an excellent balance in terms of toebox height.

At 25.6 mm, it provides enough vertical space to avoid feeling restrictive while still delivering the secure foothold and confidence that runners expect for track racing.

As we mentioned earlier, the Cloudspike Amplius 2 skips a full-length carbon plate, allowing for a more flexible ride than many competing spikes. This was reflected in our 30-degree bend test, where it required just 12.7N of force.

At 5.7 oz or 162g, the Cloudspike Amplius 2 delivers a competitive weight that never feels like a drawback on the track. However, based on what we've seen from other brands, we believe there's still room for On to trim 10% or even 15% in the next iteration.

Many spikes achieve strong airflow by using extremely delicate fabrics, but the Cloudspike Amplius 2 feels more substantial and refined, giving the upper a premium look and feel.

The mesh features a thin mesh through the forefoot, allowing air to move. Based on both our visual inspection and real-world testing, we found that this area does an excellent job of preventing excessive heat buildup during hard track sessions.

The engineered upper impressed us with its premium appearance, but this is not new for On shoes.

Under the microscope, we found a carefully constructed zoned mesh that balances lightweight performance with durability, avoiding the paper-thin feel often seen in elite track spikes.

We awarded its breathability a strong 4/5 rating. The zoned mesh delivers excellent ventilation through the forefoot and midfoot, although it falls just short of the most open and airy uppers we've ever tested.

The midfoot shank likely contributed to this result, as we measured a torsional rigidity of 11.3 Nm, placing the Cloudspike Amplius 2 almost exactly in line with the current lab average.

The heel counter of the Amplius 2 incorporates some structure rather than the ultra-flexible designs we've encountered in some competing spikes. We rated it at 2/5.

In our view, this will appeal to runners who appreciate a touch of rearfoot support and comfort without sacrificing the lightweight feel expected from a racing model.

Stability is one of the standout traits of the Cloudspike Amplius 2, and much of that comes from its remarkably broad forefoot platform.

Our calipers measured 102.3 mm in this area, an exceptionally high figure for a track spike that creates a large and confidence-inspiring landing zone.

The heel is also noticeably wider than what we typically see in track spikes, measuring 68.8 mm in our lab.

Most track spikes feature highly delicate uppers, but the Cloudspike Amplius 2 once again showcases On's commitment to material quality. In our durability test, it achieved an impressive 4/5 score, a standout result for such a lightweight spike.

The heel padding earned a solid 4/5 in our durability test, giving us confidence that it should hold up well over time without causing any significant concerns.

The Amplius 2 features a generously thick 3.2 mm outsole, giving it a slight advantage over many of its key competitors in this area.

We were unable to remove the insole from the Cloudspike Amplius 2, making it impossible to replace with an aftermarket option. Our measurements also revealed a thickness of exactly 3.0 mm.

On has built a strong reputation for delivering high-quality uppers and secure fits, and the Cloudspike Amplius 2 continues that trend. While we would have welcomed textured laces like those found on some competing spikes, the lacing system still provides reliable lockdown without any notable issues.

We were also pleased to find a lightly padded tongue that reaches up to 2.5 mm in thickness. In contrast, many rival spikes use ultra-minimal tongues that prioritize weight savings above all else and can feel less comfortable during longer events such as the 10000m.

The heel skips a traditional pull tab but stands out with an unusual asymmetrical seam that runs diagonally across the rear of the upper, a distinctive design detail that we rarely see in running shoes.

For an On shoe, the Cloudspike Amplius 2 is reasonably priced especially when compared to its main competitors. However, it's clearly inside the premium segment of the track spike market.

The On Cloudspike Amplius 2 features a rare 5-pin configuration, as most track spikes typically use either four or six pins. On includes a spike wrench in the box, making pin replacement quick and hassle-free.