Zipp 808 Firecrest Tubular Rear Wheel

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. With Firecrest, the latest 404 Tubular (58mm rim depth) matches the aero performance of the pre-Firecrest 808 (81mm depth). And the new 808 Tubular is faster than any competitor’s 90mm rim.

More stability.

During the design process, we realised 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-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. In both tubular and clincher versions, the wider design better protects tyres and places more rubber on the road while cornering without adding rolling resistance.