Zipp's exploration of the 303’s wider rim led to the Firecrest® technology. And now that development has come full circle with the 303 Firecrest. The new wheel features Firecrest’s signature shaping designed to optimize both halves of the wheel, which creates a rim that is significantly faster and also much easier to handle in crosswinds. At just 1,310 grams, the weight of the new 303 is virtually unchanged from its predecessor and remains one of the lightest carbon wheelsets anywhere. Its 45mm deep rim outperforms much deeper rims with a traditional V-shaped cross-section. And yet, because Firecrest technology allows us to manipulate the wheel’s centre of pressure, the new 303 handles like a box-section rim. It’s ultra-stable, and suitable for even the windiest days. And because the 303’s new 26.45mm-wide brake track (at centre) has been optimised for wider tyres, the ride quality is better than ever. Firecrest® – A better wheel in every way. Zipp's proprietary Firecrest® rim rewrote the fundamentals of wheel making, resulting in improved aerodynamics, ride quality, wheel strength and stability in even the strongest of crosswinds. As a result, the entire Firecrest family of wheels makes a bigger difference in more ways than ever. More Speed Firecrest technology, discovered as they developed their Carbon Clinchers, refocused Zipp's thinking to concentrate not only on the front half of the wheel, but also the back half. Previous rim shapes were designed to smooth airflow coming off the tyre, and tapered inward from the widest point of a toroidal bulge. But Firecrest rims have a less pronounced bulge and maintain a near-constant width almost all the way to the spoke bed. Without giving up the proven benefits of the toroidal shape, Firecrest is the first aero profile that effectively controls airflow around the back half of the wheel. Zipp used Computational Fluid Dynamics (CFD) post-processing capabilities to maximize aerodynamics and minimize wind-induced steering torque, resulting in a 202 Firecrest Carbon Clincher that is faster and better handling than a classic box-section road wheel. Zipp's Firecrest rim shape improves stability by moving the wheel’s centre of pressure aft and downward to sit almost directly over the steering axis, where wind-induced steering torque has a minimal effect. More Stability During the design process for Firecrest, Zipp realized that the advanced mathematics and massive computing power that helped them create a faster wheel could also help reduce the impact of crosswinds on handling. Using computational fluid dynamics (CFD) software, Zipp discovered subtle variations in rim shape that improve stability without increasing aerodynamic drag. By moving the center of pressure – the focal point of side forces on the rim – to its optimal location near the steering axis, Firecrest offers stable, predictable handling at every wind angle. With the 303 Firecrest Carbon tubular they have achieved a near neutral steering torque. In real-world conditions, Firecrest rims are markedly more stable than other rims of equal or even shallower depth. More Strength As Zipp discovered when developing the Zipp 303 to thrive under unforgiving conditions at the Spring Classics, a wider rim increases lateral stiffness for sprinting and cornering yet offers greater vertical compliance for more control, comfort, and durability on rough surfaces. The same holds true for Firecrest rims. The 303 Firecrest is a proven performer on the open road in both tubular and Carbon Clincher versions, the wider design places more rubber on the road while cornering without adding rolling resistance. The new wheels retain all the small details that make Zipp wheels what they are. Exposed spoke nipples sit in the aerodynamic shadow of the rims, keeping serviceability simple without compromising speed. And Zipp's signature ABLCâ„¢ rim dimples squeeze every last second of performance possible. To complete the package, Zipp® has refined its venerable 88/188 hubset, reshaping the hub body and pushing the non-drive-side flange and bearing out by 7.5mm on the rear hub to increase overall stiffness and strength….
– Zipp 303 Firecrest Carbon Tubular Rear Wheel 2015 Performance Wheels – £745.5 (RRP – £)
