Zipp 353 NSW wheelset review: is comfort the new aero?

Zipp 353 NSW wheelset review: is comfort the new aero?

The high-end road wheel world is going through a transition period. While in recent years the industry has obsessed over watts of drag saved and yaw angles, the talk is noticeably shifting to what’s actually faster in the real world. 

Zipp is a name synonymous with aero. The brand played a large role in the creation of the aero wheel market and progressed it further than most. However even Zipp is beginning to change its tune, and the marketing for its latest range of 40-ish-millimetre-deep wheels waxes lyrical about almost every performance attribute except aerodynamic superiority. Personally, I find this an interesting transition and one that’s on its way to becoming more widespread in the industry. 

And it’s this transition that makes Zipp’s 353 NSW – its new flagship do-it-all road or gravel race wheel – quite an interesting product to cover. At US$4,000 for a pair, this tubeless-only and disc-only wheelset is almost priced to be a conversation starter. And having spent some time on them I can see that while these are exceptionally nice wheels to ride, I’m left questioning the value proposition. 

There are obviously a whole lot of interesting tech and design decisions behind these pricey wheels, and so I decided I best write a word for every dollar they cost (just joking … but also not). 

Story Highlights

  • What: Zipp’s top-tier disc-brake do-it-all road wheelset.
  • Weight: 1,294 g, including tubeless tape and valves.
  • Price: US$4,000 / AU$6,027 (pair)
  • Highs: Undeniably smooth and controlled ride, stable, great warranty, impressively light, easy repair and service.
  • Lows: Price, no good for skinnier rubber, must use tubeless tyres, not for the aero lovers, a rare smidge of rotor rub at the front, price.

No skinny rubber here

Intended to be a pinnacle product, the wavy-shaped 353 NSW (New Speed Weaponry) offers an effective 45 mm-deep rim and sits in Zipp’s wheel line-up as the do-it-all performance road wheel. It’s effectively the price-no-object halo version of the 5 mm shallower 303 Firecrest (US$1,939), a wheel that itself sits at a premium over Zipp’s base-level 303 S (US$1,327). All three are pitched as versatile and modern wheels for use across road and gravel riding. 

Like the mid-tier 303 Firecrest, the 353 NSW features a 25 mm internal width hookless (TSS) rim design that demands the use of compatible tubeless tyres. With such a wide rim, Zipp says those tyres must have at least a 28 mm printed width and be run at no more than 72.5 psi. In reality, most 28 mm tyres will sit beyond a measured 30 mm width on these rims. For example, Schwalbe’s Pro Ones in a 28 mm measure at an actual 31.3 mm, while Continental’s new GP5000 S TL in a 30 mm width come in at an actual 32.5 mm. 

A rim this wide is going to make the tyre wider than its printed size.

Those wanting to run 40-50 mm wide gravel tyres on these rims can do so with no issue, but I suspect most keen on such a premium wheel will be predominately looking to keep them away from pointed rocks. 

With such voluminous rubber matched with lower running pressures, the 353 NSW aims to offer lower rolling resistance, increased ride comfort, and better grip – and this is the basis for many of the performance claims related to these wheels. Of course, the lower tyre pressures (60 psi on average, according to Zipp) achieve much of that, but Zipp is confident that its wider rim provides better tyre support than a narrower rim at such low pressures.

Zipp claims these are the most efficient wheels for general riding on mixed road surfaces and perhaps with a little dirt thrown in. And interestingly, the 353 NSW and 303 Firecrest share these benefits. 

A wide internal rim width and a hookless rim wall are not necessarily related. In a recent CyclingTips Nerd Alert podcast, we sat down with Zipp’s product manager Bastien Donzé to talk about all things hookless rims and why Zipp has decided to trade-in the option of open tyre compatibility. In short, Zipp believes that hookless is the answer to creating a carbon rim that defies the old rule that things can’t be stronger, lighter, and cheaper. It could be argued that the 303 S and 303 Firecrest achieve all three, but ‘cheaper’ isn’t a feature to be seen with the 353 NSW. 

Hookless rims are otherwise known as Tubeless Straight Side (TSS).

Hookless rims certainly offer benefits but they also carry two obvious downsides. Firstly, you must run a compatible tubeless tyre (but you can run a tube within). The second is that the industry is currently in a transition period to making hookless-compatible tubeless road tyres. Thankfully signs are that this is a temporary transition. For example, Continental just updated its GP5000 tubeless tyre to be compatible. No, not all popular tyre options can currently be used with these rims but I believe this situation will wholly improve in the near future.  

Aero things 

The 353 NSW is an easy one to spot from a distance as it features Zipp’s ‘Sawtooth’ rim profile that sees the 353’s rim depth flow between 42.7 and 46.5 mm. 

First introduced with the original (and deeper) 454 NSW, the wavy shape was initially released with talk of biomimicry research and the role of the tubercles found on humpback whales. The general idea was that the undulating shape produced a wheel that simulated the aero efficiency of a deeper rim with the crosswind stability of a shallower one. Zipp has since stopped talking about whales, and I was surprised to hear Donzé state that the shape only offers a marginal aerodynamic advantage on a rim of this depth.   

“We actually think our Sawtooth profile only provides a small stability benefit on the 353,” he said. “The reason is simple: Sawtooth provides the most aero and stability benefits on deep profile rims, which is the reason it came out initially on 454 and 858. As the rim becomes shallower, the aerobalance benefits also become smaller.“ So why use the Sawtooth profile at all? I’ll get to that in the next section. 

Other details on the rim include Zipp’s intricate ‘Hyperfoil’ nodes and ‘Hexfin’ dimples that are the successor to the golf ball-like dimpling. According to Donzé, these do assist with keeping the airflow attached to the rim for longer and reduce the chance of stalling. And while no specific figures were shared, Donzé said “they do play a role in drag reduction and stability.“ 

A closer look reveals plenty of fine details in the rim surface.

Identical front and back, the 353’s rims are covered in unique little aero details but perhaps miss the big picture. Compare those measured tyre widths above to the 30.65 mm exterior width of the rim, and straight away, you can see that these wheels don’t meet the often referenced 105% rule and are therefore not going to please the aero-obsessed. In fact, according to Donzé, the 353 NSW did not spend design time in a wind tunnel. 

Those after a Zipp-branded, aero, optimised road wheel for use on smoother surfaces should look to the 404 Firecrest and 454 NSW wheels. These wheels feature a 2 mm narrower internal rim width that allows the use of a 25 mm tyre and therefore can hit the 105% rule. And when set up with their respective narrowest allowed tyres, the 454 NSW is said to sit at about 1.5-2 watts faster (at 45 km/h) when compared to the 353 NSW. No data was shared for how the 353 NSW compares to the 303 Firecrest. And of course, Donzé points out that the 353 NSW’s wider rim and wider required tyre will win back time on rougher surfaces. 

Even a 28 mm (printed) tyre is wide enough to break the 105% rule.

Clearly, Zipp is no longer solely focused on aerodynamic excellence, especially when it comes to a mid-depth wheel like the 353 NSW. A sceptical view of this scenario is that advanced aerodynamic design is not the golden ticket to sales it once was. The potential for aerodynamic advantage has dwindled in recent years as brands have figured out the low hanging fruit and are now often playing within the margin of error of a wind tunnel. The days of selling solely on one’s wind-cheating merit started decaying when generic wheel brands began copying such proven profiles. 

An optimistic view (and the side of the fence I mostly sit on) is that the market is maturing, and many of the big names are now clearly looking beyond the wind tunnel and are finally recognising that people ride bikes outdoors. Brands are now addressing the obvious issues of handling and stability in blustery conditions and are perhaps recognising that designing for a wind tunnel isn’t the best path for many riders. 

Zipp has partnered with aerodynamic test machinery experts AeroLab to perform outdoor aerodynamic and rolling resistance testing to take the place of indoor testing. This real-world testing is helping to provide more relevant data and is informing (and confirming) new areas for performance gains. Still, it’s early days for this tech and in the case of the 353 NSW, the company’s previous test resulted in corrupted and unusable data. The test involving the 353 NSW is yet to be repeated.  

“Aero is not everything – it is only one component of speed, contrary to what the bike industry (and Zipp too, in all fairness) has been saying for many years,” said Donzé. “There are conditions in the real world where it’s faster to be less aero, as long as you have higher rolling efficiency and vibration damping. As a result, there’s no point in saying which of 353 or 454 is faster – it all depends on your ride style and the type of rides you are doing.

“For high-speed rides on flat to undulating terrain and clean roads, 454 is probably the ticket. For longer rides, on rougher roads and with bigger elevation change; 353 is the better option.”

And we’re back to focussing on weight

Wider tyres and the advent of disc brakes have seen road bike weights trend upward, and it sure seems that wheel brands are once again pursuing the goal of fewer grams. 

The 303 Firecrest dropped a whopping 300 grams from its predecessor, and at about 1,400 grams with tubeless tape and valves it’s now by no means a heavy option. The 353 NSW manages to shave a further 100 grams while offering a deeper rim profile and marginally higher lateral stiffness. 

My front and rear sample wheels tipped the scales at 596 g and 698 g respectively (1,294 g for the pair with XDR driver body), including the pre-installed tubeless rim tape and the alloy tubeless valves. Now those weights aren’t the very lowest out, but they’re certainly pretty minuscule for a disc brake wheelset that features 24 Sapim CX-Ray steel bladed spokes front and rear and that maintains a decent rim depth and a wide internal width.

A large contributor to the fewer grams comes from the Sawtooth rim profile, something that also allows the use of slightly shorter spokes, too. “The reason we’re using this profile on a 303 depth is that Sawtooth provides structural benefits for the rim: thanks to that shape, the rim becomes stronger and stiffer at a lighter weight”, explained Donzé, who later went on to summarise the design as offering the best combination of aero and lightweight. A 353 NSW rim weighs just 341 g.

Low wheelset weight is always the sum of all parts, but certainly, the rims play the main role here.

Of course, such a detailed rim design carries an increased cost. “Sawtooth rims are more labour-intensive than Firecrest wheels – their profiles require significantly more time to layup and cure,” said Donzé. Both the 353 and 303 Firecrest rims are produced in-house within the USA.

Also more expensive are the graphics which get printed directly onto the rim surface. Unlike the decals used on Zipp’s more affordable wheels, these are said to be lighter, fade-free, and won’t peel. 

A look inside the hub 

Zipp’s new Cognition V2 hubs also shave off a few grams and are designed to roll more freely than the ZR1 DB found in the Firecrest wheels. How much more freely do you ask? I have no idea, but the wheels spin for a hell of a long time. 

Zipp’s previous generation Cognition hub featured an intricate array of magnets and magic to provide engagement, and if things went wrong then no fun was had. By comparison, the Cognition V2 is vastly simpler in its design, it now offers a faster pick up (54T), is said to have lower friction, and of course, improved durability. With two drive rings that mesh with each other, the design isn’t all that different to being a vastly oversized version of DT Swiss’ EXP hub design. 

Those “Axial Clutch” drive rings offer an intricate shape made with metal injection moulding. Pushing them together is a rather unique Sylomer spring assembly, or put more simply, the spring is made of lightweight foam and yet functions like a metal wave washer. That foam isn’t the stuff used in your couch, but rather is commonly found as a damper in power tools or in the medical imagery field, and is said to hold its mechanical properties over time. 

The ratchet rings are lubricated with oil, not grease, and are kept shielded by a large seal that’s pressed into the hub shell (take care when removing this). Zipp suggests cleaning and re-oiling the drive mechanism every 100 hours of use. It’s a process that should only take a couple of minutes and doesn’t even require the cassette to be removed from the freehub – just yank on the cassette with the wheel out of the bike and you’ll gain access. The Sylomer spring does soak up some of the lubricant, and while I had assumed that was intentionally done to act as a lubricating oil reservoir for the drive rings, that is apparently not the design intent. 

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