Zipp 858 NSW Wheels Review for Time Trials and Triathlon

Last May, Zipp unveiled the latest version of its 858 NSW, aerodynamic wheels designed for those battling the clock on the road or in triathlon. Now even lighter despite an impressive profile, they are engineered to deliver tangible performance gains in the real world. We tested them at different intensities on a time trial bike, with stunning results.

By Guillaume Judas – Photos: ©3bikes.fr

Since its inception almost 40 years ago, the Zipp brand has always invested in the pursuit of optimal aerodynamics as the primary driver of performance. And even today, the ultimate evolution of the 858 NSW and the Super-9 (which we will discuss in a few days) demonstrates how crucial the wheel profile is in the quest to shave seconds, especially when battling the clock alone, whether in a time trial race or a medium- and long-distance triathlon. But like many frame and bike brands now limited in their evolution by UCI regulations or available technologies, Zipp has recently understood the importance of working on the overall real-world efficiency of the proposed system, meaning on the road with all the variations in terrain, elevation, and road surface that one is likely to encounter. According to Zipp, this is a “balanced strategy to overcome the four barriers to gaining and maintaining speed while riding: wind resistance, gravity, rolling resistance, and vibrations.”

The American brand adopted this philosophy with the 303 S and 303 Firecrest, then the 353 NSW, and more recently with the 454 NSW and 404 Firecrest, before extending it even to the most specific wheels in the range, since they are intended exclusively for time trial efforts: the 808 Firecrest, 858 NSW, and Super-9. All these new-generation Zipp wheels are lighter and feature wider rims for mounting larger tires, are only available for disc brakes and with hookless rims, in order to best combine aerodynamics, comfort, and versatility on almost all terrains.

Faster on all terrains

The 858 NSW therefore benefit from this philosophy, even if they are very specific and intended for pure time trial and triathlon use. The very deep rim depth indeed makes them unusable in mass-start competitions, according to the new UCI regulations from January 1, 2026 (which limit rim depth to a maximum of 65 mm). Nevertheless, with an iconic sawtooth wavy shape that varies from 82 to 85 mm, the 858 NSW are designed to best combine a very aerodynamic profile with crosswind stability equivalent to shallower rims.

The 23 mm internal width and 27 mm external width, optimized for 700×28 tires, also contribute to significantly improved stability compared to the previous 858 NSW, despite a slightly shallower rim. According to Zipp, this width reduces tire deformation and decreases rolling resistance, offering an additional advantage over competing options with 23 or 25 tire widths, which are supposedly more aerodynamically efficient. Furthermore, thanks to hookless technology, the wider tire bead combined with the external rim shape provides a smoother and more aerodynamic transition between the tire sidewalls and the wheel.

According to Zipp, there is also an advantage in terms of comfort: “a wider bead interface allows for the use of a wider tire, and thus a lower pressure. This improves overall efficiency, reduces rider fatigue, and offers better grip on uneven terrain.” An essential characteristic for long-distance triathletes, who must run a half or full marathon after the cycling course.

In terms of constraints, the 858 NSW require tubeless tires compatible with hookless mounting, from a minimum of 28 mm to a maximum of 35 mm (28 mm recommended). You can find the list of compatible tires on this table provided by Zipp.

While the brand strives to optimize wheel performance in all areas, it continues to rely on aerodynamics pushed to the smallest details, such as the famous dimples on the rims (“golf ball” style) or the directly printed logos, to promote control of airflow around the wheel.

But above all, Zipp offers a particularly lightweight solution with this brand new version of the 858 NSW equipped with the new ZR1 SL hubs. With a weight of only 1500 g for the pair of wheels, the 858 prove to be particularly versatile on time trial courses with elevation.

Hubs finally up to par

While Zipp has been a generally cutting-edge wheel brand since 1988, the same cannot be said for the hubs used until these very latest generations. Play in the bearings, unreliable bearings, failing freehub bodies… problems have been numerous even on the highest-end models. These issues finally seem completely resolved with the new ZR1 SL hubs, which are lightweight, high-performance, and finally very reliable, as we have observed on a pair of 353 NSW wheels that we have been riding for several thousand kilometers in all weather conditions.

Weighing 304 g (the pair) and featuring ceramic bearings, they are lighter than the previous model, and with a freehub body offering 66 points of engagement, reactivity is immediate with the slightest acceleration. It should be noted that the spoke anchoring point is classic (20 front and rear), which allows the use of non-specific steel spokes on the 858 NSW. This is an undeniable advantage for maintenance, although we would have appreciated the use of even lighter carbon spokes, which are increasingly found among competitors for wheels in this price range.

Lighter, more versatile

On the road, the very reasonable weight of the 858 NSW compared to other very aerodynamic wheels with equivalent rim depth is surprising. On a time trial bike, you feel more lively, more at ease, when tackling false flats in a seated position, or when getting out of the saddle to climb a steeper gradient. The 858 NSW remain very stiff and deform very little under stress. But the 300 g saved compared to most competing models prove to be formidably efficient on hilly courses or with frequent accelerations. It also represents a significant energy saving on long courses.

This weight gain does not mean a decrease in inertia at high speed. Once launched, the 858 NSW allow for maintaining an excellent cruising speed, only slightly lower than that found with a disc wheel like the Zipp Super-9, which we will discuss later.

On the time trial bike, of course, you feel the high crosswind effect inherent to this type of wheel. But in terms of feel, they are very close to the Roval CLX 64 for those who know them, wheels that are no longer in the catalog but are 20 mm shallower and about a hundred grams heavier.

With a road bike, you still end up with a somewhat anachronistic setup, which is in any case no longer accepted by UCI regulations today. Although particularly light, the 858 remain relatively demanding if you stick to a casual ride at an average of 30 or 32 km/h. They are stiff and require quite precise bike handling, rather unusual with a classic bike.

In accordance with Zipp’s recommendations for hookless rims, we stayed below 5 bar of pressure throughout our test rides with the 858 NSW. That’s 2 bar less than with 25 mm tires. A world of difference. Not only was the gain in comfort and traction on poorly surfaced roads noticeable, but also, the almost perfect tire shape on the rim caused no sensation of crushing during out-of-the-saddle efforts or strong accelerations with a very large gear.

Ideal for long and challenging triathlons

For time trials of 15 to 20 km, we prefer a combination of the 858 NSW front wheel and a Super-9 rear wheel for raw performance. However, the 858 seem particularly well suited for challenging triathlons, with distance and elevation, where they stand out as arguably the most versatile aerodynamic wheels on the market thanks to their light weight and comfort. The price remains very high, although the wheels are, fortunately, guaranteed for life.

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