Zipp's 404 Firestrike Carbon Clincher Wheels pick up where the lauded Firecrest wheels left off. At 58mm deep, it hits the sweet spot between fast as hell and actually manageable in a crosswind. If you have a big race in questionable weather, you want the 404 Firestrikes under you. The Firecrest was Zipp's first crack at a toroidal rim shape namely, something that wasn't just a deep V. Its rounded profile and wider rim bed allowed air to flow more smoothly from tire to rim and back remembering, of course, that air has to flow over both the front and back of a rim on its journey past the rider. This width had the added benefit of making clinchers the more aerodynamically advantageous tire choice, which is a relief to anyone who's put on a spare tubie before. One of the biggest remaining strikes against carbon wheels is their braking performance. Simply put, smooth carbon rims don't slow down that well, and are susceptible to heat. Zipp's engineers took that problem as a personal mission, and the result is called Showstopper Technology, a Silicon Carbide textured surface that performs as well in wet conditions as it does dry.