You don’t need to spend long looking at the new Zipp 454 NSW to realise what the brains in Indianapolis have spent their time working on to develop the company’s latest wheelset.
Called ‘HyperFoils’ (the first of many trademarked names associated with these wheels), the brains at Zipp say that this unique saw-tooth profile increases stability under crosswinds, allowing riders to run a deeper rim without the risk of losing good handling.
Between 53mm and 58mm deep, Zipp claims that the 454 NSW – a carbon clincher rim – represents a “total change in the dynamic of the wheel industry,” according to advanced development engineer Michael Hall.
They well expect their competitors to follow suit. You could be looking at the future of bike wheels.
The 454 NSW is the result of four years, 36 prototypes, 252 wind tunnel hours and goodness knows how many trademarks; on top of the SawTooth profile and the HyperFoil bumps, there are HexFin dimples (the hexagonal dents in the rim) to control air flow, the Showstopper brake surface and Impress graphic printing technology.
The Americans clearly love a good trademark.
“We have several patents on the rim shape. I’ll just leave it at that,” adds product manager Jason Fowler.
All of that curved carbon doesn’t come easy; each wheel takes 12 hours to produce. “I can tell you, making these wheels is extremely difficult,” says engineer Ruan Trouw.
36 tonne marine mammals are not the obvious place to look for design cues for road bike wheels, but Zipp claim that the humpback whale, specifically the notches on the whales’ pectoral fins called ‘tubercles’, inspired the hyperfoil design.
When the whales change direction their fins turn to face the flow of water, just like a wheel rim facing a crosswind.
If you fall into the camp of ‘aficionados and technophiles’ who Zipp say these wheels will appeal to, you might be interested to know that the hyperfoils work as vortex generators, creating turbulent air that sticks to the wheel.
The problem for bike handling is that in crosswinds, vortices apply forces to the wheel and create instability and unpredictability. Zipp claim that compared to normal rim shapes, their hyperfoils make these vortices smaller, more frequent and more regular, thus reducing instability.
This only works in one direction, however. Don’t put these wheels on the wrong way round.
“There is an arrow,” says Hall.