Optimizing the revolutionary Firecrest aero-rim concept for an 82 mm depth and the distinct airflow pattern of clincher tyres required Zipp to evaluate a slew of minutely varied prototypes through CFD, or computational fluid dynamics, software and in the wind tunnel. At 27.5 mm wide, the final version is the fastest deep-section carbon clincher in the world. Yet, with a weight of only 980 grams, it more than holds its own on the climbs. With Firecrest’s unparalleled approach to the wheel’s centre of pressure, the 808 Firecrest Carbon Clincher also handles crosswinds with the stability you’d normally associate with a much shallower rim making the 808 Carbon Clincher ideal for non-disc-legal courses like Kona. Plus, the wide rim shape provides efficient power transfer along with comfort and durability, making it an excellent choice for just about any terrain and riding style. For triathletes and road racers seeking superior aero performance, stable handling, and the convenience of clinchers, there’s no faster all-around wheelset than the 808 Firecrest Carbon Clincher. 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 we developed our Carbon Clinchers, 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 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. The performance benefits are substantial the 808 Firecrest as used by Australian Pete Jacobs proved this by blasting the 112 mile cycling leg at Kona a pair of 808 Firecrest wheels to capture the 2012 Ironman® World Championship. “The crosswinds were never blowing me across the road. I always felt in control,” Jacobs said. “During the race I was thinking, “Wow, these 808s feel great.” 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 center 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, 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. With the 404 Firecrest Carbon Clincher, 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 404 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. Now, add to that our Carbon Clincher technology. Zipp's exclusive resin, based on materials used in motorsports braking systems, effectively tolerates the incredible spikes in heat caused by braking to provide you with reliability and stopping power. Combine that with our Tangente Platinum brake pads and you have unmatched performance, all with the ease of use of a clincher. Carbon Clinchers – A new chapter in speed Zipp Carbon Clinchers have been described as the most heavily anticipated wheels of all time. During the two-year development process, we designed new clincher-specific approaches to prototyping, testing, materials, and manufacturing. The end result is worth the wait. Optimized Materials When a wheel with carbon braking surfaces encounters a long, technical descent, spikes in rim temperature and tyre pressure can impact braking and handling – especially with carbon clinchers. To solve this challenge, chemists and engineers from our composites supplier made repeated visits to Zipp and developed an exclusive heat-resistant resin based on the materials used in motorsports brake systems. This proprietary technology improves heat dissipation so substantially that all Zipp Carbon Clinchers pass stringent CEN safety standards without any limitations on rider weight or brake pad choices – a certification that no other full-carbon clincher wheelsets have achieved. Optimized aerodynamics Wind tunnel development is a cornerstone of how Zipp creates the world’s fastest wheels. Using semi-structural prototypes, we can quickly and accurately evaluate dozens of potential rim shapes. But the prototyping technology that works for tubulars can’t support fully inflated clinchers. So we developed an entirely new system where plastic skins are applied to a fully structural interior skeleton. This allowed us to refine carbon clincher rim shapes that perfectly match the distinct airflow patterns created by clincher tyres. This process led directly to the Firecrest rim shape that has improved aerodynamics, stability, strength, and comfort in our tubular and clincher wheels. Optimized ride quality With the Firecrestâ„¢ rim shape, Zipp Carbon Clinchers are the first to offer the superior aerodynamics, handling, comfort, and road feel of a wide rim body. The added width between the clincher hook beads increases air volume in the tyre, which means a lower chance of pinch-flatting. And with our exclusive heat-resistant resin, Tangente cork composite brake pads, and angled braking surfaces, Zipp Carbon Clinchers provide smooth, pulsation-free stopping power under all condition. The 808 Firecrest Carbon Clincher is built with a the latest iteration of our 188 rear hub, the V9, along with new spoke-lacing pattern for the rear wheel – refinements that result in improved stiffness and durability. The new 188/V9 hub has larger precision Swiss steel bearings for increased durability. Our new “virtual 3 cross” lacing on both sides of rear wheel improves stiffness, achieving 3 cross stiffness in a 2 cross pattern with a new spoke geometry. The 188/V9 has 25 percent more torsional stiffness than a leading competitive hub. This measure of stiffness is crucial for the direct power transfer to the rear wheel for out-of-the saddle sprints and climbs. The new hub also is laterally (side-to-side) stiffer that its rival or predecessor…
– Zipp 808 Firecrest Carbon Clincher Rear Wheel 2015 Performance Wheels – £897.25 (RRP – £)
