In the go fast world of aerodynamic carbon rims, the Zipp Firecrest 303 is the standard by which all other rims are judged. This latest version, the 303 Firecrest Disc Brake wheel, uses the same aerodynamic carbon fiber rims, with only slight modifications for use with disc brakes. Most fans will be relieved to learn that the 303 Firecrest was left virtually untouched when the disc brake model was created. While most rims need to be strengthened for use with disc brakes, Zipp's engineers found that the 303 was already capable of handling the increased braking forces. That says a lot for the 303, especially considering its weight and aerodynamics. One change that was made, however, was that Zipp discontinued the high abrasion brake track on the disc version. Because of this, the new rims are not rim brake compatible. They do, however, retain their aerodynamic dimpled surfaces, wide cross section, and deep 45mm dish. The hub is Zipp's latest 88188. This hub rolls on Swiss made stainless steel bearings and is, of course, 11 speed compatible. With the addition of the six bolt disc brake rotor mount, however, the hub width has been increased to 135mm. The last notable modification that Zipp made to its 303 is the lacing pattern. Because of the increased force that disc brakes apply to the rim, Zipp now uses a virtual three cross lacing pattern, which is much stronger than the radial pattern used on the previous 303.