Zipp's new 454 NSW wheel is radically different. While it retains the wide profile of Zipp's firecrest design, the 454 has been inspired by the fluid dynamics of the natural world.
- Zipp changes the nature of aero with the 454 NSW wheel
- How to change your bike wheels for winter
- Complete guide to winter road cycling
The humpback whale is the inspiration for the 454 NSW's intriguing shape. Michael Hall, Zipp’s chief advanced development engineer, described to us how the humpback can make large movements at speed in the water and to do this it "basically has these Vortex generators on its fins that allows the water flow to stay attached, making it able to make these extreme manoeuvres."
Zipp's NSW wheel has a Sawtooth ABLC dimple pattern, but the 454 wheel has evolved with raised Hyperfoils — inspired by the tubercles (the shaped bumps) on the pectoral fins of the humpback whale. These dimples have a hexagonal rather than round shape and act as a vortex generator, or node, like the whale.
To read more about the aero design see our article Zipp changes the nature of aero with the 454 NSW wheel.
Zipp 454s out on the road
I took the Zipp 454s out on the road in a variety of weather conditions and tested them back-to-back with Zipp's 404 wheel, too.
There are no claims that the 454 is faster than the 404 in traditional aero terms, but the wild shape of the rim changes from 58mm (like the 404) down to 53mm, a difference in 5mm — so the 454 isn’t a replacement for the 404, it's an additional model.
Weight wise our test pair came in at 712g for the front and 866g for the rear (including rim tapes), plus an additional 86g for the skewers. Compared to our test 404 NSWs (700g/850g) that’s 28g heavier, though still lighter than the non-NSW 404 (by 92g).
Braking from the 454's Showstopper brake track — which combines a deeper brake track section with a siped pattern and uses a Silicon Carbide — is the same as the 404 and equally impressive, offering progressive stopping power in the dry, while wet weather performance outstrips most of the competition.
The rear freehub used on the Cognition hubs is carried over from the 404 NSW and uses Zipp’s magnetic clutch (to eliminate mechanical drag when freewheeling), which is brilliant, and you’ll notice when riding in the bunch the gains this gifts you.
Conventional freehubs use a spring and pawl ratchet mechanism, which generates friction when coasting and acts like a very weak drum brake, slowing you down. The new design disengages the ratchet mechanism when coasting effectively friction-free, meaning you’ll hold precious speed for longer.
Inside you’ll find a pair of injection moulded metal ratchet rings that instantly engage when you pedal (turned clockwise), but as soon as they aren’t being driven the 36 points of engagement are separated by powerful magnets forcing them apart.
As the system relies on magnets to operate, it requires no lubrication or maintenance. This ‘Axial clutch’ is low profile compared to a standard set up, which means that the freehub body can be switched to an XD driver should you want to use SRAM’s wide-range one-by gears.
The new hubs both feature factory-set preload bearings that require no adjustment and are lighter than previous hubs — tipping the scales at 110g (f) and 225g (r).
The wheel construction of the new rim, cognition hubs and Sapim CX-Ray spokes revels in stiffness and feels even more rigid than the 404 NSW when I tried them on back-to-back comparison test rides.
The most telling of my test rides was on a cold January day, with weather warnings for high winds (25-33mph).
On calmer days the 454's handling is noticeably lighter than that of the 404, it's almost as if you're riding a smaller depth rim, such is the ease with which you can change directions or correct your line mid-corner.
The gains however are marginal; they are easier to live with and ride significantly better the worse the weather gets — especially in the wind. Days like this are rare though, yet the improvements as an all-round wheel are definitely present. The 454 if anything rides and feels like its shallower cousin the 303, but you get the added aero gains from the deeper rim.
It's just that compared to the already excellent 404 NSW I'm not sure that the extra £1,350 premium over them is quite worth it (even if, as Zipp tells us, it takes 12 hours to make a single pair of 454s at its Indianapolis facility). If I'd already invested in the brilliant 404 NSWs, I wouldn’t be rushing to change.
If you DO have deep pockets and are in the market for a 50mm deep wheelset then these certainly should be on your shopping list.
They ship with Ti skewers, wheel bags, valve extenders, brake pads, tubes and rim tape.