For every rider, every discipline, and every ability level, aero wheels make a difference. Every test we’ve ever run has confirmed this basic truth, and we’ve never seen data from anyone else that argues differently.

With the revolutionary Firecrest rim shape in our 303, 404, 808 Tubulars and Carbon Clinchers, Zipp wheels make a bigger difference in more ways than ever. Not only is Firecrest more aerodynamic than any other rim design, it improves handling in crosswinds, wheel strength and overall ride quality.

Discovered as we developed our Carbon Clinchers, Firecrest refocused our 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 tire, 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.

The performance benefits are substantial. The 303 Firecrest (45mm rim depth) is 8 percent faster than the wheel that took victories at Paris-Roubaix and the Tour of Flanders. With Firecrest, the 404 Tubular (58mm rim depth) matches the aero performance of the pre-Firecrest 808 (81mm depth). And the 808 Tubular is faster than any competitor’s 90mm rim. At Kona, the women’s course record in the grueling 112-mile cycling leg was set using a 404 Firecrest-808 Firecrest combo.

During the design process, we realized that the advanced mathematics and massive computing power that helped us create a faster wheel could also help reduce the impact of crosswinds on handling. Using computational fluid dynamics (CFD), we’ve 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. In real-world conditions, Firecrest rims are markedly more stable than other rims of equal or even shallower depth.

As we discovered with designs like the Paris-Roubaix and two-time Tour of Flanders-winning 303, 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, including the new 303 Firecrest. In both tubular and Carbon Clincher versions, the wider design better protects tires and places more rubber on the road while cornering without adding rolling resistance.