Zipp has extended the Firecrest lineup to include Tubeless Carbon Clincher rims optimized for Disc Brake hubs. This is a trick wheelset at home in all your playgrounds.
You are familiar with Firecrest, but this tubeless and disc-brake specific rim is new. First, take notice of the brake track. That’s right, it’s gone and ABLC dimples go all the way up the sides. This is new design, with not only the rim shape changed, but the material moved around. The rim remains 45mm deep, but the width has mushroomed out to 29.9mm, and the internal width 21mm. As you can imagine the shape means wider tires. 25mm is as narrow as you’ll want to go, but the 28mm width offers better aerodynamics still and going even wider still offers great aerodynamics. This rim works best with wide tires.
It’s also stronger. Without having to deal with the force of brakes squeezing the rim, they were able to move material around. And the strength you can rely on. Feel free to drop the tire pressure. Not only will the rim withstand whatever you’re putting in front of it, but the molded internal ridges lock tires in place, even at low pressures.
Zipp employs their 77/177D hub set, which was purpose-built for disc braking. There are 24 aero Sapim CX-Ray spokes, both front and rear. A cross pattern is necessary in front to counter the forces of braking. The flanges are slightly taller to work around the six-hole rotor mounts and the 17mm axle. While you can see that the spokes have a two-cross pattern, it actually possesses the lateral stiffness of a three-cross thanks to the size of the flanges and the orientation of the spokes. The benefits of the design are more aero and shorter spokes.
For rear wheels, Zipp offers both a Campagnolo-compatible, and Shimano/SRAM-compatible cassette body. The latter comes with a spacer for 9/10/11-speed cassettes. In both cases, the 177D hub body allows you to install a SRAM XDR Driver body for super-wide range gearing.
The wheel comes with quick release, endcaps to convert the hub for thru-axle use (endcaps are hand swappable), rim strip (taped at the factory), and valve extender.
The Zipp 303 Firecrest Carbon Clincher Disc Brake wheelset is light, aero, and tough enough for the roughest cyclocross, or gravel racing, has to offer.