They’re 58mm deep, but how swift and sta­ble are these 454s?

220 Triathlon Magazine - - CONTENTS - Robin Wilmott

All the new­est swim, bike and run kit on the mar­ket, tested by the 220 team. Plus, fi­nal ver­dicts de­liv­ered on three long-term test items

For non-draft­ing triath­letes who don’t like rim wear and want good brak­ing, the disc ver­sion of Zipp’s uniquely-pro­filed 454 NSW wheelset is here. Its rim widths of 17mm in­ter­nally, and 27.72mm max­i­mum ex­ter­nally are de­rived from the 58mm deep Zipp 404s, with the name change due to the 5mm height vari­a­tion of its in­ner cir­cum­fer­ence.

That dis­tinc­tive de­sign is based on Biomimicry – ap­ply­ing nat­u­ral-world so­lu­tions to man­made ob­jects. Tak­ing the tu­ber­cles on the lead­ing edge of Hump­back whales’ pec­toral fins as in­spi­ra­tion, Zipp came up with the Saw­tooth pro­file to im­prove air­flow across the rim. Aim­ing to stay top of the Kona Wheels Count, the re­cently un­veiled 858 NSW ap­plies the same shap­ing to the TT-friendly 808 wheelset.

They’re not tube­less com­pat­i­ble and our set weighed 1,642g, which is good but not ex­cep­tional. The Saw­tooth pro­file com­prises 24 Hy­per foils, each fea­tur­ing dim­ples on the sur­face, which to­gether in­crease wind vor­tex-shed­ding fre­quency. Zipp say that the higher num­ber of smaller air vor­tices cre­ated are more pre­dictable, and shed­ding them more of­ten re­ally im­proves wheel sta­bil­ity, while re­duc­ing aero­dy­namic drag and side force at all wind yaw an­gles.

Large hub flanges, 24 J-bend spokes and rigid rims make the 454 NSWs ac­cel­er­a­tive, with an in­stant re­sponse to crank in­puts. The Zipps are ef­fi­cient up­hill and, al­though we can’t prove they’re more aero than the 404s, we doubt they’re slower, based on road tests.

In calm con­di­tions, there’s lit­tle to tell them apart from other com­peti­tors, but when speed or the wind picks up, there is. We de­lib­er­ately headed out on gusty, hard days on hilly, twisty routes to see how the wheels coped with con­stantly shift­ing strong winds. This rim height isn’t im­mune from cross­winds – we felt a slight nudge as gusts hit – but it was never more than that, and didn’t war­rant tight­en­ing our grip, or mov­ing from the ex­ten­sions. Pass­ing gaps in hedges, turn­ing cor­ners across the wind, and de­scend­ing all gave us sim­i­larly mi­nor con­cern. The front wheel briefly loads up with side force from the wind, then re­turns to neu­tral, feeling nearer to 35mm than 58mm deep.

The fact that we were so un­con­cerned rid­ing these wheels on days when we’d usu­ally have plumped for some­thing shal­lower speaks vol­umes. Ul­ti­mately, bet­ter con­trol is more ef­fi­cient; not bat­tling the bike saves pre­cious en­ergy that you can use later. The con­fi­dence these wheels bring will al­low you to go faster for longer.

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