On Cloudultra 2 Review: Corrected 27/21mm Trail Geometry

On Cloudultra 2 Review: Corrected 27/21mm Trail Geometry

Disclosure: TrainingPlan has not hands-on tested this exact model. This research-based review uses On's launch technical sheet and two independent exact-model evaluations. No Amazon US listing is currently verified for publication.

Quick Verdict

The On Cloudultra 2 is a neutral trail shoe aimed at sustained running on mixed, generally runnable terrain. Its construction combines Helion superfoam, articulated CloudTec geometry, a flexible TPU Speedboard, a close sock-like upper, and Missiongrip rubber. On's June 2023 launch technical sheet specifies 27mm at the heel, 21mm at the forefoot, a 6mm drop, and reference weights of 295g for a men's US 8.5 and 265g for a women's US 7. Those convert to approximately 10.4 and 9.3 ounces. Launch price was MSRP: $179.

This is not a tall, marshmallow-soft ultra shoe. The relatively modest brand stack, firm Helion feel, low-profile outsole, and flexible build make it more coherent on dirt roads, buffed singletrack, gravel, hiking routes, and mixed road-to-trail outings. Cloudultra 3 now supersedes it, so version 2 needs the right fit and a meaningful discount.

Key Specifications

What Changed

The prior catalog listed 34/28mm, an 8.8-ounce women's reference, and copy that treated “ultra” as proof of abundant cushion. The exact launch document instead supports 27/21mm and 265g, or 9.3 ounces, for the women's reference size. The runtime record and article now use those source-backed values.

The previous Amazon destination also lacked a dated exact-generation title match in the affiliate audit. It is removed from both the live catalog and the dormant update map. That does not mean the model has never appeared on Amazon; it means we cannot responsibly label that ASIN as Cloudultra 2 inventory today.

The Important Measurement Conflict

RunRepeat's laboratory review measured 30.2mm at the heel, 20.0mm at the forefoot, and a 10.2mm drop. Its sample weight was 296g, almost identical to On's 295g reference, but the measured geometry is materially different from On's 27/21mm and 6mm launch specification.

Those values should not be averaged. Stack measurements can vary with size, reference points, compression, and method. Following our catalog policy, the specification table retains the brand launch geometry while this review presents the laboratory result where it can affect a purchase decision. Runners sensitive to drop should try the actual pair rather than treating either number as a guarantee of on-foot feel.

Ride and Intended Use

The articulated platform bends more freely than a carbon-plated racing shoe. Helion and the Speedboard create a controlled transition, but independent testing characterizes the foam as firm rather than plush. The shoe can roll smoothly once loaded, especially on forgiving surfaces, yet its modest forefoot stack leaves more terrain feedback than the product name suggests.

The Missiongrip outsole emphasizes ground contact and durability. RunRepeat measured 2.5mm lugs, below the norm for aggressive trail shoes. That makes the Cloudultra 2 a better fit for dry hardpack, forest roads, gravel, and moderate singletrack than deep mud, loose off-camber slopes, or terrain where tall directional lugs are essential. Read the trail shoe guide for more specialized options.

Fit and Sizing

The knitted, sock-like upper wraps the midfoot and helps exclude small debris. On describes the fit as snug, and the standard-width platform does not provide a labeled wide option. The FlipRelease forefoot element can create a little more space when feet swell, but it cannot change the last or turn a narrow match into a true wide fit.

Start at normal running-shoe size and verify heel hold, toe clearance, and midfoot pressure on an incline. Do not size up solely to gain width if the extra length compromises control. Our running-shoe fit guide explains the difference.

What Works Well

The upper is breathable, the outsole coverage is durable, and the flexible platform is useful beyond running. Independent testing found the shoe comfortable for walking and hiking as well as moderate trail mileage. The design also stays stable without a broad maximal footprint, which can appeal to runners who dislike towering trail platforms.

Tradeoffs

Weight is high relative to the 27/21mm brand stack. Forefoot protection is modest, the shallow lugs are not mud-specific, and the standard-only fit limits accessibility. The MSRP: $179 launch price was also ambitious for an EVA/OBC-based foam and non-carbon plate. No fixed mileage lifespan is promised; track rubber, foam, upper security, and comfort using the replacement guide.

Who Should Consider This Shoe

Consider it if you want a firm, flexible standard-width shoe for dry hardpack, gravel, hiking, or moderate long trail runs and have confirmed the close upper fit.

Who Should Look Elsewhere

Look elsewhere for deep-mud lugs, a roomy wide fit, low weight relative to stack, or genuinely plush maximal cushioning.

Cross-Brand Comparison

The Salomon Ultra Glide 2 offers a similarly smooth long-distance purpose with deeper 3.5mm lugs and a roomier-feeling upper. The Altra Olympus 6 is much heavier but adds a 33mm zero-drop platform and Vibram Megagrip. The HOKA Speedgoat 6 is a more conventional technical-trail reference.

Same-Brand Comparison

Within On, the Cloudvista 2 targets mixed and road-to-trail running, while Cloudultra 3 is the direct successor. Do not assume the successor has identical fit, geometry, or ride.

Value

The MSRP: $179 launch price was demanding; as a superseded model, Cloudultra 2 makes the strongest case when the exact fit works and the discount is substantial.

Final Verdict

Cloudultra 2 is best understood as a secure, firm, flexible trail shoe for moderate long-distance terrain. Its audited launch specification is 27/21mm with a 6mm drop—not 34/28mm—and its shallow outsole and substantial weight are important limitations. Buy it only when the fit, terrain, and legacy price align.