Zipp has revealed a new 454 NSW carbon clincher – featuring a distinctive ‘SawTooth’ rim shape – that it claims is its highest performing wheelset ever.
The key innovation here is the SawTooth rim architecture (a little confusing because Zipp already has ABLC SawTooth Technology that refers to a specific dimple configuration) that’s intended to reduce aerodynamic drag and side force.
“SawTooth accomplishes this with a series of patented fin-shaped HyperFoil nodes along the inner diameter of the rim that work together with our new HexFin ABLC dimples for improved airflow,” says Zipp.
That’s quite a lot of jargon already. We’ll come back to it in a sec!
“The result is Zipp’s highest performing wheelset ever realised with both aero-drag reduction and reduced side force at all wind yaw angles. This is important because higher wind yaw angles are where bike handling is most affected by the wind.”
Although clearly related to drag and stability, Zipp doesn’t say exactly how it has concluded that the 454 NSW is the ’highest performing wheelset’ in the range.
So, those terms: HyperFoil is the name Zipp gives to the individual nodes on the rim – each individual 'tooth' that's 53mm deep at the bottom and 58mm at the tip.
HexFin ABLC dimples are the hexagonally shaped depressions on each Hyperfoil.
“The angular shape of each dimple increases boundary layer mixing to help keep airflow attached to the rim for reduced aerodynamic drag and improved stability in crosswinds,” says Zipp.
“To further improve the effectiveness of the hexagonal dimples, they are arranged in fin-shaped clusters made up of variable sized dimples that work in concert with each Hyperfoil of a SawTooth rim.”
Crikey, I hope you’re keeping up! Ready for a bit more detail?
“The HyperFoils and HexFin ABLC dimples help to stabilise handling in gusting wind by increasing wind vortex shedding frequency. Lower frequency shedding produces larger, more powerful vortices.
“In cycling terms, this unstable situation is often referred to as ‘buffeting’. The higher frequency vortex shedding produced by SawTooth creates a greater number of smaller, less powerful, yet more predictable vortices leading to greater wheel stability.”
The idea is that this increases your control and saves energy, leading to faster riding.
Zipp says that the inspiration for the SawTooth design came from the irregular shape of the leading edge of humpback whale pectoral fins. No, really. This led to the testing of 36 distinct rim shapes and prototypes with different depths and numbers of HyperFoils.
The 454 NSW features Zipp’s existing Showstopper brake track – a moulded in texture with silicon carbide particles suspended in the surface resin – designed to enhance braking performance, particularly in wet conditions, and ImPress graphics which are printed directly on to the wheels so as not to compromise the effects of the dimples.
Like Zipp’s other NSW wheels, the 454 uses the brand’s Cognition hubset. This features its Axial Clutch that uses magnets rather than springs to move and engage the ratchet rings in the freehub, the idea being to reduce friction when coasting.
The wheels are built with Sapim CX-Ray spokes, 18 at the front, 24 at the rear.
The brake track width is 26.4mm and the maximum rim width is 27.8mm.
Zipp claims wheel weights of 690g (front) and 835g (rear), a total of 1,525g.
The front wheel is priced £1,550 and the rear is £1,950, a total of £3,500. You don’t need us to point out that that’s a helluva large price tag. The Zipp 202 NSW wheels that have just arrived at road.cc for review are £2,369.
Each wheel includes a skewer, rim tape, inner tube, brake pads, valve extender and wheel bag.
Mat has worked for loads of bike magazines over 20+ years, and been editor of 220 Triathlon and Cycling Plus. He's been road.cc technical editor for eight years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a past winner of the Cycling Media Award for Specialist Online Writer.