Following on from their successes with the Zipp 808 NSW at the Ironman World Championship and the Elite Women's UCI World Time Trial Championships, Zipps engineers have been beavering away in their top secret lab, know as The Nest, to bring you the second set of wheels to come from their hard work...the Zip 404 NSW.
With the 808 aimed specifically at the triathlon and TT market, the 58mm 404 is squarely pointed at road riders with Zipp claiming that the 404s are strong enough to handle the cobbles of Flanders while being light enough to inspire sprints out of the corners. So, why chose these over the groundbreaking Firecrest or the Firestrike (basically the Firecrest if they'd hit the gym and taken they're protein)?
The Devils in the Dimples
The very cleaver people in The Nest have decreased the side forced by a claimed 34% over the Firecrest design, this has been achieved through tests in the real world, wind tunnel and on the computer where Zipp found that if they reworked their signature dimple design has been reworked with 12 nodes that are designed to start aiding crosswind stability at a rider speed of 20mph. I think we'll all agree that 20mph is very much within reach of all us mere mortals. The dimples work by keeping the rate that air sheds off the wheel under control. A less disrupted air path means more balance between the exposed and shielded sides of the rim, meaning that the rim works more constantly at higher yaw angles (the angle of the wind) and so improving the stability in crosswinds. In theory this means that more of those precious watts go into making the bike move forward rather than merely trying to hold your line in poor conditions. Zipp have given this design the snappy name of ABLC Sawtooth... yup, snappy isn't it.
Out with the Ratchet in with the Magnets
The other big change that Zipp have made is in the hub design. Zipp debuted the new magnet based Congnition hub on their 808 NSW and now it comes to the 404. This new hub is designed to reduce friction while coasting which will give you a faster wheelset.
The thinking from Zipps engineers is that the ratchet design in a conventional mechinism with springs and pawls exerts a lot of friction when coasting so acts like a mild drum break and slows you down. The new Cognition design disengages the ratchet mechanism with magnets when you stop pedaling and start coasting. Using the same 36 points of engagement that you'll find on other Zipp hubs, a pair of metal ratchet rings instantly engage when you pedal and magnets force them apart when you stop. As an added bonus, the system requires no lubrication and only a light oil is used inside the hub instead of grease. The new hubs also feature factory set pre-load bearings that require no adjustment and, for you weight weenies out there, they tip the scales at 110g for the front and 225g for the rear.
This brings us to the final part of the puzzle, the braking surfaces. Zipp have incorporated their brake track from the FireStrikes, snappily titled ShowStopper which combines a deeper brake track section with a pattern. This is made from a silicon carbide material that Zipp say improves power modulation and heat management.
The Zipp 404 NSW are now in stock at York Cycleworks, come in and see them for yourselves!