by Kevin Mackinnon
Zipp has been leading the way in the world of aerodynamic wheelsets for almost two decades. But the wheel market has become considerably more competitive over the last few years, with a lot of companies making very fast wheel sets.
With the rich wheel landscape, it was important for Zipp to come out with something that would reassert its position at the top of the aero-wheel food chain. In August, the company did just that with a pair of speedy options that will help you in your time trials. The new wheelsets are the latest iterations of the 808 Firecrest and 858 NSW. Zipp’s engineers have made some big changes that make the wheels faster, but also more comfortable to ride.
Total System Efficiency (TSE)
In 2018, the Zipp engineers did some major testing—not in a wind tunnel, but out on the road. They then designed a special way to test rolling resistance and vibration losses over a variety of surfaces. Through all this testing they began to learn that some of the decisions they were making in the wind tunnel, when it came to wheel design, could actually slow people down in the real world.
For example, remember the days when you used to pump your tires up to 100, or even 120 p.s.i.? Turns out that when you lower tire pressure, you actually can save energy. You can also reduce rolling resistance by changing the way the tire contacts the ground. The studies showed that wider rims paired with wider tires promotes less rolling tire deflection, resulting in lower rolling resistance. That wide tire/wide rim combination is also more aerodynamic when it comes to the rim-to-tire transition. The wider the tire, the lower the tire pressure you can run, which, Zipp’s testing found, “can increase overall system efficiency, reduce rider fatigue, and offer better handling in rough conditions.”
So what does all that mean in simple terms? Thanks to the wider rims and tires, along with lower tire pressures, you’ll ride faster and use less energy absorbing road shock.
Meet the new 808 and 858 wheelsets
Zipp relied on all these findings when it designed the latest iterations of the 808 and 858 wheels. The hoops are more aerodynamic, but also offer better rolling resistance and are less affected by vibration losses. They are also considerably lighter (274 g lighter for the 808 and 254 g for the 858) than the previous versions. The 808 Firecrest tubeless disc brake wheelset weighs 1,635 g (752 g front, 883 g rear), while the 858 NSW tubeless disc brake wheelset weighs just 1,530 g (719 g front, 811 g rear).
Both models feature hookless rims, which allowed Zipp shed some of the weight. (Hookless rims don’t have the material, the hooks for tire beads, that you’re used to seeing with regular clincher wheels. The new wheels are designed to work with tubeless tires. You can use a tube with these rims, but only combined with a tubeless tire.) The U-shaped tire profile of the tubeless tire on these rims works really well to decrease rolling resistance.
The HexFin ABLC dimple pattern enhances aerodynamics
The 858 NSW rims continue to use the undulating 82- to 85-mm rim depth (sawtooth profile) that provides the best aero and crosswind performance. The wheels come with a Cognition V2 hubs that feature Axial Clutch V2 technology to reduce drag and friction. The 808 Firecrest rims are 80-mm deep and include the ZR1 hubs. The 808 wheels offer some pretty amazing aero properties for considerably less money than the 858 option. If you don’t have to deal with massive crosswinds, they are definitely worth a look.
Both wheels perform at their best with 28-mm-wide tires. You can use Zipp’s tire pressure guide to dial in the perfect pressure for your needs.
The Zipp 858 NSW Tubeless Disc-brake wheelset retails for US$4,400.
The Zipp 808 Firecrest Tubeless Disc-brake wheelset retails for US$2,300.
This story is presented by SRAM