There’s long been a reason that you’ve seen so many pros, and, for that matter, so many age group athletes racing on Zipp wheels at the Ironman World Championship. The company 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, too.
Which is why it was important for Zipp to come out with something that would reassert it’s position at the top of the aero wheel food chain. Last month the company did just that with a pair of speedy options that we’ll see a lot of the world’s fastest full-distance athletes competing on in Kona this October. The new wheelsets are the latest iterations of the 808 Firecrest and 858 NSW, and, as we’re used to seeing with Zipp, the company hasn’t just tweaked things with the latest models. The engineers at the company have made some big changes that make the wheels faster, but also more comfortable to ride so you’ll have more energy for the run after a hard bike effort. The end result is both a faster bike split and a faster all-around race.
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 (basically a monstrous treadmill for bikes). 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 psi? Turns out that when you lower tire pressure you actually can save energy, and 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 offers 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, so you’ll run faster too.
Meet the new 808 and 858 wheelsets
Taking all this into consideration, Zipp’s latest iterations of the 808 and 858 wheels utilize all this research to provide more aerodynamics, but also improve rolling resistance and 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 to redesign the new wheels to lose that weight. (Hookless rims don’t have the bead that you’re used to seeing with regular clincher wheels. These 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 (figure above) works really well to decrease rolling resistance.
The 858 NSW rims continue to utilize the undulating 82- to 85-mm rim depth (Sawtooth profile) that provides the best aero and cross-wind performance. They come with a cognition V2 Subset that features 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 that the 858 option. For those who aren’t going to have to deal with Kona-like crosswinds, they are definitely worth a look.
Both wheels perform at their best with 28 mm 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